NOAA SWPC Alerts, Watches and Warnings

The National Oceanic and Atmospheric Administration Space Weather Prediction Center (NOAA SWPC) is the official space weather government agency from the United States that provides alerts, watches and warning for space weather disturbances. Below you will find the latest space weather alerts, watches and warnings issued by the NOAA SWPC.

Sunday, 27 April 2025

16:32 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3455
Issue Time: 2025 Apr 27 1632 UTC

ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2025 Apr 27 1605 UTC
Station: GOES-19




Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

Thursday, 24 April 2025

17:16 UTC

Space Weather Message Code: WARK04
Serial Number: 4939
Issue Time: 2025 Apr 24 1716 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4938
Valid From: 2025 Apr 24 0655 UTC
Now Valid Until: 2025 Apr 25 0900 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

11:36 UTC

Space Weather Message Code: WARK04
Serial Number: 4938
Issue Time: 2025 Apr 24 1136 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4937
Valid From: 2025 Apr 24 0655 UTC
Now Valid Until: 2025 Apr 24 1800 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

07:09 UTC

Space Weather Message Code: ALTK04
Serial Number: 2552
Issue Time: 2025 Apr 24 0709 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 24 0703 UTC
Synoptic Period: 0600-0900 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

06:56 UTC

Space Weather Message Code: WARK04
Serial Number: 4937
Issue Time: 2025 Apr 24 0656 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 24 0655 UTC
Valid To: 2025 Apr 24 1200 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Monday, 21 April 2025

23:56 UTC

Space Weather Message Code: WARK04
Serial Number: 4936
Issue Time: 2025 Apr 21 2356 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4935
Valid From: 2025 Apr 21 0218 UTC
Now Valid Until: 2025 Apr 22 1159 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

20:34 UTC

Space Weather Message Code: ALTK05
Serial Number: 1756
Issue Time: 2025 Apr 21 2034 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 21 2033 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

13:54 UTC

Space Weather Message Code: WARK06
Serial Number: 577
Issue Time: 2025 Apr 21 1354 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2025 Apr 21 1353 UTC
Valid To: 2025 Apr 21 1800 UTC
Warning Condition: Onset
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

13:54 UTC

Space Weather Message Code: ALTK05
Serial Number: 1755
Issue Time: 2025 Apr 21 1354 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 21 1352 UTC
Synoptic Period: 1200-1500 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

11:46 UTC

Space Weather Message Code: ALTK05
Serial Number: 1754
Issue Time: 2025 Apr 21 1146 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 21 1142 UTC
Synoptic Period: 0900-1200 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

10:10 UTC

Space Weather Message Code: WARK05
Serial Number: 2026
Issue Time: 2025 Apr 21 1010 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 21 1010 UTC
Valid To: 2025 Apr 21 2359 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

09:34 UTC

Space Weather Message Code: WARK04
Serial Number: 4935
Issue Time: 2025 Apr 21 0934 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4934
Valid From: 2025 Apr 21 0218 UTC
Now Valid Until: 2025 Apr 21 2359 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

02:25 UTC

Space Weather Message Code: ALTK04
Serial Number: 2551
Issue Time: 2025 Apr 21 0225 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 21 0224 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

02:18 UTC

Space Weather Message Code: WARK04
Serial Number: 4934
Issue Time: 2025 Apr 21 0218 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 21 0218 UTC
Valid To: 2025 Apr 21 1200 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

01:48 UTC

Space Weather Message Code: WATA30
Serial Number: 251
Issue Time: 2025 Apr 21 0148 UTC

WATCH: Geomagnetic Storm Category G2 Predicted

Highest Storm Level Predicted by Day:
Apr 21: None (Below G1) Apr 22: G2 (Moderate) Apr 23: G2 (Moderate)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

Sunday, 20 April 2025

00:56 UTC

Space Weather Message Code: ALTK05
Serial Number: 1753
Issue Time: 2025 Apr 20 0056 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 20 0055 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

00:41 UTC

Space Weather Message Code: ALTK04
Serial Number: 2550
Issue Time: 2025 Apr 20 0041 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 20 0038 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

00:38 UTC

Space Weather Message Code: WARK05
Serial Number: 2025
Issue Time: 2025 Apr 20 0038 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 20 0038 UTC
Valid To: 2025 Apr 20 1200 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

00:06 UTC

Space Weather Message Code: WARK04
Serial Number: 4933
Issue Time: 2025 Apr 20 0006 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 20 0005 UTC
Valid To: 2025 Apr 20 1200 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Saturday, 19 April 2025

20:47 UTC

Space Weather Message Code: WATA30
Serial Number: 250
Issue Time: 2025 Apr 19 2047 UTC

WATCH: Geomagnetic Storm Category G2 Predicted

Highest Storm Level Predicted by Day:
Apr 20: None (Below G1) Apr 21: None (Below G1) Apr 22: G2 (Moderate)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

14:55 UTC

Space Weather Message Code: WARK04
Serial Number: 4932
Issue Time: 2025 Apr 19 1455 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4931
Valid From: 2025 Apr 19 0218 UTC
Now Valid Until: 2025 Apr 19 2359 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

02:27 UTC

Space Weather Message Code: ALTK04
Serial Number: 2549
Issue Time: 2025 Apr 19 0227 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 19 0227 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

02:19 UTC

Space Weather Message Code: WARK04
Serial Number: 4931
Issue Time: 2025 Apr 19 0219 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 19 0218 UTC
Valid To: 2025 Apr 19 1500 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

00:07 UTC

Space Weather Message Code: ALTTP2
Serial Number: 1411
Issue Time: 2025 Apr 19 0007 UTC

ALERT: Type II Radio Emission
Begin Time: 2025 Apr 18 2345 UTC
Estimated Velocity: 349 km/s



Description: Type II emissions occur in association with eruptions on the sun and typically indicate a coronal mass ejection is associated with a flare event.

Friday, 18 April 2025

04:48 UTC

Space Weather Message Code: WARK05
Serial Number: 2024
Issue Time: 2025 Apr 18 0448 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 18 0447 UTC
Valid To: 2025 Apr 18 1200 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

04:02 UTC

Space Weather Message Code: ALTK04
Serial Number: 2548
Issue Time: 2025 Apr 18 0402 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 18 0357 UTC
Synoptic Period: 0300-0600 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

01:52 UTC

Space Weather Message Code: WARK04
Serial Number: 4930
Issue Time: 2025 Apr 18 0152 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 18 0152 UTC
Valid To: 2025 Apr 18 1200 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Thursday, 17 April 2025

10:12 UTC

Space Weather Message Code: WARK04
Serial Number: 4929
Issue Time: 2025 Apr 17 1012 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4928
Valid From: 2025 Apr 15 1705 UTC
Now Valid Until: 2025 Apr 17 1800 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Wednesday, 16 April 2025

23:13 UTC

Space Weather Message Code: WARK06
Serial Number: 576
Issue Time: 2025 Apr 16 2313 UTC

EXTENDED WARNING: Geomagnetic K-Index of 6 expected
Extension to Serial Number: 575
Valid From: 2025 Apr 16 1315 UTC
Now Valid Until: 2025 Apr 17 0600 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

23:13 UTC

Space Weather Message Code: WARK05
Serial Number: 2023
Issue Time: 2025 Apr 16 2313 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2022
Valid From: 2025 Apr 15 1730 UTC
Now Valid Until: 2025 Apr 17 0900 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

21:40 UTC

Space Weather Message Code: ALTK05
Serial Number: 1752
Issue Time: 2025 Apr 16 2140 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 16 2136 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

20:54 UTC

Space Weather Message Code: ALTK08
Serial Number: 50
Issue Time: 2025 Apr 16 2054 UTC

ALERT: Geomagnetic K-index of 8, 9-
Threshold Reached: 2025 Apr 16 2055 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G4 - Severe

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 45 degrees Geomagnetic Latitude.
Induced Currents - Possible widespread voltage control problems and some protective systems may mistakenly trip out key assets from the power grid. Induced pipeline currents intensify.
Spacecraft - Systems may experience surface charging; increased drag on low earth orbit satellites, and tracking and orientation problems may occur.
Navigation - Satellite navigation (GPS) degraded or inoperable for hours.
Radio - HF (high frequency) radio propagation sporadic or blacked out.
Aurora - Aurora may be seen as low as Alabama and northern California.

19:32 UTC

Space Weather Message Code: ALTK07
Serial Number: 182
Issue Time: 2025 Apr 16 1932 UTC

ALERT: Geomagnetic K-index of 7
Threshold Reached: 2025 Apr 16 1925 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G3 - Strong

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude.
Induced Currents - Power system voltage irregularities possible, false alarms may be triggered on some protection devices.
Spacecraft - Systems may experience surface charging; increased drag on low Earth-orbit satellites and orientation problems may occur.
Navigation - Intermittent satellite navigation (GPS) problems, including loss-of-lock and increased range error may occur.
Radio - HF (high frequency) radio may be intermittent.
Aurora - Aurora may be seen as low as Pennsylvania to Iowa to Oregon.

19:31 UTC

Space Weather Message Code: WARK07
Serial Number: 125
Issue Time: 2025 Apr 16 1931 UTC

WARNING: Geomagnetic K-index of 7 or greater expected
Valid From: 2025 Apr 16 1930 UTC
Valid To: 2025 Apr 17 0000 UTC
Warning Condition: Persistence
NOAA Scale: G3 or greater

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude.
Induced Currents - Power system voltage irregularities possible, false alarms may be triggered on some protection devices.
Spacecraft - Systems may experience surface charging; increased drag on low Earth-orbit satellites and orientation problems may occur.
Navigation - Intermittent satellite navigation (GPS) problems, including loss-of-lock and increased range error may occur.
Radio - HF (high frequency) radio may be intermittent.
Aurora - Aurora may be seen as low as Pennsylvania to Iowa to Oregon.

18:53 UTC

Space Weather Message Code: WARK04
Serial Number: 4928
Issue Time: 2025 Apr 16 1853 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4927
Valid From: 2025 Apr 15 1705 UTC
Now Valid Until: 2025 Apr 17 1200 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

18:52 UTC

Space Weather Message Code: WARK05
Serial Number: 2022
Issue Time: 2025 Apr 16 1852 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2021
Valid From: 2025 Apr 15 1730 UTC
Now Valid Until: 2025 Apr 17 0300 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

18:52 UTC

Space Weather Message Code: WARK06
Serial Number: 575
Issue Time: 2025 Apr 16 1852 UTC

EXTENDED WARNING: Geomagnetic K-Index of 6 expected
Extension to Serial Number: 574
Valid From: 2025 Apr 16 1315 UTC
Now Valid Until: 2025 Apr 17 0000 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

18:45 UTC

Space Weather Message Code: ALTK06
Serial Number: 628
Issue Time: 2025 Apr 16 1845 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2025 Apr 16 1838 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

18:32 UTC

Space Weather Message Code: ALTK05
Serial Number: 1751
Issue Time: 2025 Apr 16 1832 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 16 1828 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

16:44 UTC

Space Weather Message Code: ALTK06
Serial Number: 627
Issue Time: 2025 Apr 16 1644 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2025 Apr 16 1634 UTC
Synoptic Period: 1500-1800 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

15:26 UTC

Space Weather Message Code: ALTK05
Serial Number: 1750
Issue Time: 2025 Apr 16 1526 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 16 1520 UTC
Synoptic Period: 1500-1800 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

14:24 UTC

Space Weather Message Code: ALTK07
Serial Number: 181
Issue Time: 2025 Apr 16 1424 UTC

ALERT: Geomagnetic K-index of 7
Threshold Reached: 2025 Apr 16 1418 UTC
Synoptic Period: 1200-1500 UTC

Active Warning: Yes
NOAA Scale: G3 - Strong

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude.
Induced Currents - Power system voltage irregularities possible, false alarms may be triggered on some protection devices.
Spacecraft - Systems may experience surface charging; increased drag on low Earth-orbit satellites and orientation problems may occur.
Navigation - Intermittent satellite navigation (GPS) problems, including loss-of-lock and increased range error may occur.
Radio - HF (high frequency) radio may be intermittent.
Aurora - Aurora may be seen as low as Pennsylvania to Iowa to Oregon.

13:25 UTC

Space Weather Message Code: WARK07
Serial Number: 124
Issue Time: 2025 Apr 16 1325 UTC

WARNING: Geomagnetic K-index of 7 or greater expected
Valid From: 2025 Apr 16 1325 UTC
Valid To: 2025 Apr 16 1800 UTC
Warning Condition: Onset
NOAA Scale: G3 or greater

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude.
Induced Currents - Power system voltage irregularities possible, false alarms may be triggered on some protection devices.
Spacecraft - Systems may experience surface charging; increased drag on low Earth-orbit satellites and orientation problems may occur.
Navigation - Intermittent satellite navigation (GPS) problems, including loss-of-lock and increased range error may occur.
Radio - HF (high frequency) radio may be intermittent.
Aurora - Aurora may be seen as low as Pennsylvania to Iowa to Oregon.

13:24 UTC

Space Weather Message Code: ALTK06
Serial Number: 626
Issue Time: 2025 Apr 16 1324 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2025 Apr 16 1321 UTC
Synoptic Period: 1200-1500 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

13:13 UTC

Space Weather Message Code: ALTK05
Serial Number: 1749
Issue Time: 2025 Apr 16 1313 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 16 1313 UTC
Synoptic Period: 1200-1500 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

13:07 UTC

Space Weather Message Code: WARK06
Serial Number: 574
Issue Time: 2025 Apr 16 1307 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2025 Apr 16 1315 UTC
Valid To: 2025 Apr 16 2100 UTC
Warning Condition: Persistence
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

12:39 UTC

Space Weather Message Code: WARK04
Serial Number: 4927
Issue Time: 2025 Apr 16 1239 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4926
Valid From: 2025 Apr 15 1705 UTC
Now Valid Until: 2025 Apr 17 0000 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

12:38 UTC

Space Weather Message Code: WARK05
Serial Number: 2021
Issue Time: 2025 Apr 16 1238 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2020
Valid From: 2025 Apr 15 1730 UTC
Now Valid Until: 2025 Apr 16 2100 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

12:00 UTC

Space Weather Message Code: ALTK05
Serial Number: 1748
Issue Time: 2025 Apr 16 1200 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 16 1159 UTC
Synoptic Period: 0900-1200 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

05:35 UTC

Space Weather Message Code: WARK05
Serial Number: 2020
Issue Time: 2025 Apr 16 0535 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2019
Valid From: 2025 Apr 15 1730 UTC
Now Valid Until: 2025 Apr 16 1500 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

05:35 UTC

Space Weather Message Code: WARK04
Serial Number: 4926
Issue Time: 2025 Apr 16 0535 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4925
Valid From: 2025 Apr 15 1705 UTC
Now Valid Until: 2025 Apr 16 1800 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

01:34 UTC

Space Weather Message Code: ALTK05
Serial Number: 1747
Issue Time: 2025 Apr 16 0134 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 16 0130 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

Tuesday, 15 April 2025

22:29 UTC

Space Weather Message Code: ALTK06
Serial Number: 625
Issue Time: 2025 Apr 15 2229 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2025 Apr 15 2223 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

22:04 UTC

Space Weather Message Code: ALTK05
Serial Number: 1746
Issue Time: 2025 Apr 15 2204 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 15 2200 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

21:13 UTC

Space Weather Message Code: SUMSUD
Serial Number: 286
Issue Time: 2025 Apr 15 2113 UTC

SUMMARY: Geomagnetic Sudden Impulse
Observed: 2025 Apr 15 1859 UTC
Deviation: 68 nT
Station: BOU

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

19:52 UTC

Space Weather Message Code: ALTK06
Serial Number: 624
Issue Time: 2025 Apr 15 1952 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2025 Apr 15 1944 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

18:59 UTC

Space Weather Message Code: ALTK05
Serial Number: 1745
Issue Time: 2025 Apr 15 1859 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 15 1859 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

18:50 UTC

Space Weather Message Code: WARK06
Serial Number: 573
Issue Time: 2025 Apr 15 1850 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2025 Apr 15 1900 UTC
Valid To: 2025 Apr 16 0600 UTC
Warning Condition: Onset
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

17:32 UTC

Space Weather Message Code: ALTK05
Serial Number: 1744
Issue Time: 2025 Apr 15 1732 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 15 1732 UTC
Synoptic Period: 1500-1800 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

17:31 UTC

Space Weather Message Code: WARK05
Serial Number: 2019
Issue Time: 2025 Apr 15 1731 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 15 1730 UTC
Valid To: 2025 Apr 16 0600 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

17:29 UTC

Space Weather Message Code: ALTK04
Serial Number: 2547
Issue Time: 2025 Apr 15 1729 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 15 1725 UTC
Synoptic Period: 1500-1800 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

17:07 UTC

Space Weather Message Code: WARK04
Serial Number: 4925
Issue Time: 2025 Apr 15 1707 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 15 1705 UTC
Valid To: 2025 Apr 16 1200 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

16:51 UTC

Space Weather Message Code: WARSUD
Serial Number: 242
Issue Time: 2025 Apr 15 1651 UTC

WARNING: Geomagnetic Sudden Impulse expected
Valid From: 2025 Apr 15 1729 UTC
Valid To: 2025 Apr 15 1759 UTC
IP Shock Passage Observed: 2025 Apr 15 1642 UTC

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

15:24 UTC

Space Weather Message Code: WATA50
Serial Number: 86
Issue Time: 2025 Apr 15 1524 UTC

WATCH: Geomagnetic Storm Category G3 Predicted

Highest Storm Level Predicted by Day:
Apr 16: G3 (Strong) Apr 17: G1 (Minor) Apr 18: None (Below G1)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude.
Induced Currents - Power system voltage irregularities possible, false alarms may be triggered on some protection devices.
Spacecraft - Systems may experience surface charging; increased drag on low Earth-orbit satellites and orientation problems may occur.
Navigation - Intermittent satellite navigation (GPS) problems, including loss-of-lock and increased range error may occur.
Radio - HF (high frequency) radio may be intermittent.
Aurora - Aurora may be seen as low as Pennsylvania to Iowa to Oregon.

11:16 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3454
Issue Time: 2025 Apr 15 1116 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3453
Begin Time: 2025 Apr 05 1225 UTC
Yesterday Maximum 2MeV Flux: 1464 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

Monday, 14 April 2025

23:02 UTC

Space Weather Message Code: ALTK04
Serial Number: 2546
Issue Time: 2025 Apr 14 2302 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 14 2301 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

23:01 UTC

Space Weather Message Code: WARK04
Serial Number: 4924
Issue Time: 2025 Apr 14 2301 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 14 2300 UTC
Valid To: 2025 Apr 15 1200 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

08:56 UTC

Space Weather Message Code: WARK04
Serial Number: 4923
Issue Time: 2025 Apr 14 0856 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4922
Valid From: 2025 Apr 14 0031 UTC
Now Valid Until: 2025 Apr 14 1500 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

05:12 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3453
Issue Time: 2025 Apr 14 0512 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3452
Begin Time: 2025 Apr 05 1225 UTC
Yesterday Maximum 2MeV Flux: 1150 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

04:41 UTC

Space Weather Message Code: WARK05
Serial Number: 2018
Issue Time: 2025 Apr 14 0441 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 14 0441 UTC
Valid To: 2025 Apr 14 0900 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

04:39 UTC

Space Weather Message Code: ALTK04
Serial Number: 2545
Issue Time: 2025 Apr 14 0439 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 14 0429 UTC
Synoptic Period: 0300-0600 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

00:33 UTC

Space Weather Message Code: WARK04
Serial Number: 4922
Issue Time: 2025 Apr 14 0033 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 14 0031 UTC
Valid To: 2025 Apr 14 0900 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Sunday, 13 April 2025

21:20 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3452
Issue Time: 2025 Apr 13 2120 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3451
Begin Time: 2025 Apr 05 1225 UTC
Yesterday Maximum 2MeV Flux: 2657 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

20:07 UTC

Space Weather Message Code: WATA30
Serial Number: 249
Issue Time: 2025 Apr 13 2007 UTC

WATCH: Geomagnetic Storm Category G2 Predicted

Highest Storm Level Predicted by Day:
Apr 14: None (Below G1) Apr 15: None (Below G1) Apr 16: G2 (Moderate)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

08:19 UTC

Space Weather Message Code: WARK04
Serial Number: 4921
Issue Time: 2025 Apr 13 0819 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4920
Valid From: 2025 Apr 12 1636 UTC
Now Valid Until: 2025 Apr 13 2359 UTC
Warning Condition: persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Saturday, 12 April 2025

22:45 UTC

Space Weather Message Code: WARK04
Serial Number: 4920
Issue Time: 2025 Apr 12 2245 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4919
Valid From: 2025 Apr 12 1636 UTC
Now Valid Until: 2025 Apr 13 0900 UTC
Warning Condition: persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

22:20 UTC

Space Weather Message Code: WARK05
Serial Number: 2017
Issue Time: 2025 Apr 12 2220 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 12 2220 UTC
Valid To: 2025 Apr 13 0600 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

17:46 UTC

Space Weather Message Code: ALTK04
Serial Number: 2544
Issue Time: 2025 Apr 12 1746 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 12 1746 UTC
Synoptic Period: 1500-1800 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

16:36 UTC

Space Weather Message Code: WARK04
Serial Number: 4919
Issue Time: 2025 Apr 12 1636 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 12 1636 UTC
Valid To: 2025 Apr 13 0300 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

07:03 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3451
Issue Time: 2025 Apr 12 0703 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3450
Begin Time: 2025 Apr 05 1225 UTC
Yesterday Maximum 2MeV Flux: 3362 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

Friday, 11 April 2025

23:41 UTC

Space Weather Message Code: WARK04
Serial Number: 4918
Issue Time: 2025 Apr 11 2341 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4917
Valid From: 2025 Apr 10 2243 UTC
Now Valid Until: 2025 Apr 12 1500 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

17:55 UTC

Space Weather Message Code: WARK04
Serial Number: 4917
Issue Time: 2025 Apr 11 1755 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4916
Valid From: 2025 Apr 10 2243 UTC
Now Valid Until: 2025 Apr 11 2359 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

14:08 UTC

Space Weather Message Code: WATA20
Serial Number: 1036
Issue Time: 2025 Apr 11 1408 UTC

WATCH: Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
Apr 12: G1 (Minor) Apr 13: None (Below G1) Apr 14: None (Below G1)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

05:34 UTC

Space Weather Message Code: WARK04
Serial Number: 4916
Issue Time: 2025 Apr 11 0534 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4915
Valid From: 2025 Apr 10 2243 UTC
Now Valid Until: 2025 Apr 11 1800 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

04:59 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3450
Issue Time: 2025 Apr 11 0459 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3449
Begin Time: 2025 Apr 05 1225 UTC
Yesterday Maximum 2MeV Flux: 3362 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

Thursday, 10 April 2025

22:59 UTC

Space Weather Message Code: WARK05
Serial Number: 2016
Issue Time: 2025 Apr 10 2259 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 10 2300 UTC
Valid To: 2025 Apr 11 0300 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

22:46 UTC

Space Weather Message Code: ALTK04
Serial Number: 2543
Issue Time: 2025 Apr 10 2246 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 10 2247 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

22:42 UTC

Space Weather Message Code: WARK04
Serial Number: 4915
Issue Time: 2025 Apr 10 2242 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 10 2243 UTC
Valid To: 2025 Apr 11 0600 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

08:33 UTC

Space Weather Message Code: WARK04
Serial Number: 4914
Issue Time: 2025 Apr 10 0833 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4913
Valid From: 2025 Apr 10 0107 UTC
Now Valid Until: 2025 Apr 10 1500 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

07:56 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3449
Issue Time: 2025 Apr 10 0756 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3448
Begin Time: 2025 Apr 05 1225 UTC
Yesterday Maximum 2MeV Flux: 3893 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

01:41 UTC

Space Weather Message Code: ALTK04
Serial Number: 2542
Issue Time: 2025 Apr 10 0141 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 10 0141 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

01:08 UTC

Space Weather Message Code: WARK04
Serial Number: 4913
Issue Time: 2025 Apr 10 0108 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 10 0107 UTC
Valid To: 2025 Apr 10 0900 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Wednesday, 9 April 2025

08:39 UTC

Space Weather Message Code: WARK04
Serial Number: 4912
Issue Time: 2025 Apr 09 0839 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4911
Valid From: 2025 Apr 07 2022 UTC
Now Valid Until: 2025 Apr 09 1800 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

08:38 UTC

Space Weather Message Code: WARK05
Serial Number: 2015
Issue Time: 2025 Apr 09 0838 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2014
Valid From: 2025 Apr 08 1436 UTC
Now Valid Until: 2025 Apr 09 1500 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

05:21 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3448
Issue Time: 2025 Apr 09 0521 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3447
Begin Time: 2025 Apr 05 1225 UTC
Yesterday Maximum 2MeV Flux: 10269 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

01:51 UTC

Space Weather Message Code: ALTK05
Serial Number: 1743
Issue Time: 2025 Apr 09 0151 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 09 0145 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

Tuesday, 8 April 2025

20:56 UTC

Space Weather Message Code: WARK05
Serial Number: 2014
Issue Time: 2025 Apr 08 2056 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2013
Valid From: 2025 Apr 08 1436 UTC
Now Valid Until: 2025 Apr 09 0900 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

20:56 UTC

Space Weather Message Code: WARK04
Serial Number: 4911
Issue Time: 2025 Apr 08 2056 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4910
Valid From: 2025 Apr 07 2022 UTC
Now Valid Until: 2025 Apr 09 1200 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

15:01 UTC

Space Weather Message Code: ALTK05
Serial Number: 1742
Issue Time: 2025 Apr 08 1501 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 08 1459 UTC
Synoptic Period: 1200-1500 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

14:41 UTC

Space Weather Message Code: WARK04
Serial Number: 4910
Issue Time: 2025 Apr 08 1441 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4909
Valid From: 2025 Apr 07 2022 UTC
Now Valid Until: 2025 Apr 08 2100 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

14:36 UTC

Space Weather Message Code: WARK05
Serial Number: 2013
Issue Time: 2025 Apr 08 1436 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 08 1436 UTC
Valid To: 2025 Apr 08 2100 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

06:14 UTC

Space Weather Message Code: ALTTP2
Serial Number: 1410
Issue Time: 2025 Apr 08 0614 UTC

ALERT: Type II Radio Emission
Begin Time: 2025 Apr 08 0553 UTC
Estimated Velocity: 456 km/s



Description: Type II emissions occur in association with eruptions on the sun and typically indicate a coronal mass ejection is associated with a flare event.

05:02 UTC

Space Weather Message Code: WARK04
Serial Number: 4909
Issue Time: 2025 Apr 08 0502 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4908
Valid From: 2025 Apr 07 2022 UTC
Now Valid Until: 2025 Apr 08 1500 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

04:59 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3447
Issue Time: 2025 Apr 08 0459 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3446
Begin Time: 2025 Apr 05 1225 UTC
Yesterday Maximum 2MeV Flux: 17878 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

Monday, 7 April 2025

20:39 UTC

Space Weather Message Code: ALTK04
Serial Number: 2541
Issue Time: 2025 Apr 07 2039 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 07 2039 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

20:22 UTC

Space Weather Message Code: WARK04
Serial Number: 4908
Issue Time: 2025 Apr 07 2022 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 07 2022 UTC
Valid To: 2025 Apr 08 0600 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

04:59 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3446
Issue Time: 2025 Apr 07 0459 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3445
Begin Time: 2025 Apr 05 1225 UTC
Yesterday Maximum 2MeV Flux: 9243 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

Sunday, 6 April 2025

23:58 UTC

Space Weather Message Code: WARK04
Serial Number: 4907
Issue Time: 2025 Apr 06 2358 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4906
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 07 0559 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

05:55 UTC

Space Weather Message Code: WARK04
Serial Number: 4906
Issue Time: 2025 Apr 06 0555 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4905
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 06 2359 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

05:01 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3445
Issue Time: 2025 Apr 06 0501 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3444
Begin Time: 2025 Apr 05 1225 UTC
Yesterday Maximum 2MeV Flux: 2350 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

01:55 UTC

Space Weather Message Code: WARK05
Serial Number: 2012
Issue Time: 2025 Apr 06 0155 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2011
Valid From: 2025 Apr 05 2005 UTC
Now Valid Until: 2025 Apr 06 1200 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

01:52 UTC

Space Weather Message Code: ALTK05
Serial Number: 1741
Issue Time: 2025 Apr 06 0152 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 06 0150 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

Saturday, 5 April 2025

20:33 UTC

Space Weather Message Code: WARK06
Serial Number: 572
Issue Time: 2025 Apr 05 2033 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2025 Apr 05 2032 UTC
Valid To: 2025 Apr 06 0300 UTC
Warning Condition: Onset
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

20:20 UTC

Space Weather Message Code: ALTK05
Serial Number: 1740
Issue Time: 2025 Apr 05 2020 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 05 2020 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

20:06 UTC

Space Weather Message Code: WARK05
Serial Number: 2011
Issue Time: 2025 Apr 05 2006 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 05 2005 UTC
Valid To: 2025 Apr 06 0300 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

17:56 UTC

Space Weather Message Code: WARK04
Serial Number: 4905
Issue Time: 2025 Apr 05 1756 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4904
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 06 0600 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

12:44 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3444
Issue Time: 2025 Apr 05 1244 UTC

ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2025 Apr 05 1225 UTC
Station: GOES16




Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

04:05 UTC

Space Weather Message Code: ALTK05
Serial Number: 1739
Issue Time: 2025 Apr 05 0405 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 05 0405 UTC
Synoptic Period: 0300-0600 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

03:00 UTC

Space Weather Message Code: ALTK06
Serial Number: 623
Issue Time: 2025 Apr 05 0300 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2025 Apr 05 0259 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

02:11 UTC

Space Weather Message Code: WARK06
Serial Number: 571
Issue Time: 2025 Apr 05 0211 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2025 Apr 05 0210 UTC
Valid To: 2025 Apr 05 1200 UTC
Warning Condition: Onset
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

00:51 UTC

Space Weather Message Code: ALTK05
Serial Number: 1738
Issue Time: 2025 Apr 05 0051 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 05 0051 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

00:49 UTC

Space Weather Message Code: WARK05
Serial Number: 2010
Issue Time: 2025 Apr 05 0049 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 05 0050 UTC
Valid To: 2025 Apr 05 1200 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

00:47 UTC

Space Weather Message Code: WARK04
Serial Number: 4904
Issue Time: 2025 Apr 05 0047 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4903
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 05 1800 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Friday, 4 April 2025

23:19 UTC

Space Weather Message Code: ALTK05
Serial Number: 1737
Issue Time: 2025 Apr 04 2319 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 04 2317 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

14:20 UTC

Space Weather Message Code: WARK05
Serial Number: 2009
Issue Time: 2025 Apr 04 1420 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2008
Valid From: 2025 Apr 03 1943 UTC
Now Valid Until: 2025 Apr 04 2359 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

14:20 UTC

Space Weather Message Code: WARK06
Serial Number: 570
Issue Time: 2025 Apr 04 1420 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2025 Apr 04 1418 UTC
Valid To: 2025 Apr 04 2100 UTC
Warning Condition: Onset
NOAA Scale: G2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

14:20 UTC

Space Weather Message Code: WARK04
Serial Number: 4903
Issue Time: 2025 Apr 04 1420 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4902
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 05 0600 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

13:07 UTC

Space Weather Message Code: ALTK05
Serial Number: 1736
Issue Time: 2025 Apr 04 1307 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 04 1307 UTC
Synoptic Period: 1200-1500 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

05:49 UTC

Space Weather Message Code: WARK05
Serial Number: 2008
Issue Time: 2025 Apr 04 0549 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2007
Valid From: 2025 Apr 03 1943 UTC
Now Valid Until: 2025 Apr 04 1800 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

05:48 UTC

Space Weather Message Code: WARK04
Serial Number: 4902
Issue Time: 2025 Apr 04 0548 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4901
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 04 2100 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

00:01 UTC

Space Weather Message Code: ALTK05
Serial Number: 1735
Issue Time: 2025 Apr 04 0001 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 03 2359 UTC
Synoptic Period: 2100-0000 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

Thursday, 3 April 2025

20:02 UTC

Space Weather Message Code: ALTK05
Serial Number: 1734
Issue Time: 2025 Apr 03 2002 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 Apr 03 2002 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

19:43 UTC

Space Weather Message Code: WARK05
Serial Number: 2007
Issue Time: 2025 Apr 03 1943 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 03 1943 UTC
Valid To: 2025 Apr 04 0600 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

17:56 UTC

Space Weather Message Code: WARK04
Serial Number: 4901
Issue Time: 2025 Apr 03 1756 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4900
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 04 0600 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

17:55 UTC

Space Weather Message Code: WARK04
Serial Number: 4900
Issue Time: 2025 Apr 03 1755 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4899
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 03 0600 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

09:05 UTC

Space Weather Message Code: WARK04
Serial Number: 4899
Issue Time: 2025 Apr 03 0905 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4898
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 03 1800 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Wednesday, 2 April 2025

21:12 UTC

Space Weather Message Code: WATA20
Serial Number: 1035
Issue Time: 2025 Apr 02 2112 UTC

WATCH: Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
Apr 03: None (Below G1) Apr 04: G1 (Minor) Apr 05: G1 (Minor)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

20:59 UTC

Space Weather Message Code: WARK04
Serial Number: 4898
Issue Time: 2025 Apr 02 2059 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4897
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 03 1000 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

18:24 UTC

Space Weather Message Code: SUMPX1
Serial Number: 122
Issue Time: 2025 Apr 02 1824 UTC

SUMMARY: Proton Event 10MeV Integral Flux exceeded 10pfu
Begin Time: 2025 Mar 31 1105 UTC
Maximum Time: 2025 Apr 01 0425 UTC
End Time: 2025 Apr 02 0910 UTC
Maximum 10MeV Flux: 147 pfu
NOAA Scale: S2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

11:02 UTC

Space Weather Message Code: WARPX1
Serial Number: 600
Issue Time: 2025 Apr 02 1102 UTC

EXTENDED WARNING: Proton 10MeV Integral Flux above 10pfu expected
Extension to Serial Number: 599
Valid From: 2025 Mar 31 1057 UTC
Now Valid Until: 2025 Apr 02 1800 UTC
Warning Condition: Persistence
Predicted NOAA Scale: S1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Radio - Minor impacts on polar HF (high frequency) radio propagation resulting in fades at lower frequencies.

08:51 UTC

Space Weather Message Code: WARK05
Serial Number: 2006
Issue Time: 2025 Apr 02 0851 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2005
Valid From: 2025 Apr 02 0233 UTC
Now Valid Until: 2025 Apr 02 1500 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

08:51 UTC

Space Weather Message Code: WARK04
Serial Number: 4897
Issue Time: 2025 Apr 02 0851 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4896
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 02 2100 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

02:34 UTC

Space Weather Message Code: WARK04
Serial Number: 4896
Issue Time: 2025 Apr 02 0234 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4895
Valid From: 2025 Apr 02 0123 UTC
Now Valid Until: 2025 Apr 02 1200 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

02:34 UTC

Space Weather Message Code: WARK05
Serial Number: 2005
Issue Time: 2025 Apr 02 0234 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 Apr 02 0233 UTC
Valid To: 2025 Apr 02 0900 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

01:33 UTC

Space Weather Message Code: ALTK04
Serial Number: 2540
Issue Time: 2025 Apr 02 0133 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 02 0132 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

01:23 UTC

Space Weather Message Code: WARK04
Serial Number: 4895
Issue Time: 2025 Apr 02 0123 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 02 0123 UTC
Valid To: 2025 Apr 02 0600 UTC
Warning Condition: Onset

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

00:23 UTC

Space Weather Message Code: WATA20
Serial Number: 1034
Issue Time: 2025 Apr 02 0023 UTC

WATCH: Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
Apr 02: None (Below G1) Apr 03: None (Below G1) Apr 04: G1 (Minor)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

Tuesday, 1 April 2025

23:37 UTC

Space Weather Message Code: WARPX1
Serial Number: 599
Issue Time: 2025 Apr 01 2337 UTC

EXTENDED WARNING: Proton 10MeV Integral Flux above 10pfu expected
Extension to Serial Number: 598
Valid From: 2025 Mar 31 1057 UTC
Now Valid Until: 2025 Apr 02 1200 UTC
Warning Condition: Persistence
Predicted NOAA Scale: S1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Radio - Minor impacts on polar HF (high frequency) radio propagation resulting in fades at lower frequencies.

18:15 UTC

Space Weather Message Code: SUMPX2
Serial Number: 56
Issue Time: 2025 Apr 01 1815 UTC

SUMMARY: Proton Event 10MeV Integral Flux exceeded 100pfu
Begin Time: 2025 Apr 01 0205 UTC
Maximum Time: 2025 Apr 01 0425 UTC
End Time: 2025 Apr 01 0910 UTC
Maximum 10MeV Flux: 147 pfu
NOAA Scale: S2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

10:12 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3443
Issue Time: 2025 Apr 01 1012 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3442
Begin Time: 2025 Mar 28 1410 UTC
Yesterday Maximum 2MeV Flux: 2039 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

07:14 UTC

Space Weather Message Code: SUM10R
Serial Number: 863
Issue Time: 2025 Apr 01 0714 UTC

SUMMARY: 10cm Radio Burst
Begin Time: 2025 Apr 01 0645 UTC
Maximum Time: 2025 Apr 01 0645 UTC
End Time: 2025 Apr 01 0645 UTC
Duration: 1 minutes
Peak Flux: 190 sfu
Latest Penticton Noon Flux: 172 sfu



Description: A 10cm radio burst indicates that the electromagnetic burst associated with a solar flare at the 10cm wavelength was double or greater than the initial 10cm radio background. This can be indicative of significant radio noise in association with a solar flare. This noise is generally short-lived but can cause interference for sensitive receivers including radar, GPS, and satellite communications.

07:05 UTC

Space Weather Message Code: SUMXM5
Serial Number: 287
Issue Time: 2025 Apr 01 0704 UTC

SUMMARY: X-ray Event exceeded M5
Begin Time: 2025 Apr 01 0637 UTC
Maximum Time: 2025 Apr 01 0646 UTC
End Time: 2025 Apr 01 0653 UTC
X-ray Class: M5.6
Optical Class: na
Location: N10E25
NOAA Scale: R2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact centered primarily on sub-solar point on the sunlit side of Earth.
Radio - Limited blackout of HF (high frequency) radio communication for tens of minutes.

06:51 UTC

Space Weather Message Code: ALTXMF
Serial Number: 478
Issue Time: 2025 Apr 01 0651 UTC

ALERT: X-Ray Flux exceeded M5
Threshold Reached: 2025 Apr 01 0645 UTC
NOAA Scale: R2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact centered on sub-solar point on the sunlit side of Earth. Extent of blackout of HF (high frequency) radio communication dependent upon current X-ray Flux intensity. For real-time information on affected area and expected duration please see http://www.swpc.noaa.gov/products/d-region-absorption-predictions-d-rap.

02:22 UTC

Space Weather Message Code: ALTPX2
Serial Number: 77
Issue Time: 2025 Apr 01 0222 UTC

ALERT: Proton Event 10MeV Integral Flux exceeded 100pfu
Begin Time: 2025 Apr 01 0205 UTC
NOAA Scale: S2 - Moderate

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Radiation - Passengers and crew in high latitude, high altitude flights may experience small, increased radiation exposures.
Spacecraft - Infrequent single-event upsets to satellites are possible.
Radio - Small effects on polar HF (high frequency) propagation resulting in fades at lower frequencies.

Monday, 31 March 2025

23:54 UTC

Space Weather Message Code: WARPX1
Serial Number: 598
Issue Time: 2025 Mar 31 2354 UTC

EXTENDED WARNING: Proton 10MeV Integral Flux above 10pfu expected
Extension to Serial Number: 597
Valid From: 2025 Mar 31 1057 UTC
Now Valid Until: 2025 Apr 01 2359 UTC
Warning Condition: Persistence
Predicted NOAA Scale: S1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Radio - Minor impacts on polar HF (high frequency) radio propagation resulting in fades at lower frequencies.

11:21 UTC

Space Weather Message Code: ALTPX1
Serial Number: 357
Issue Time: 2025 Mar 31 1121 UTC

ALERT: Proton Event 10MeV Integral Flux exceeded 10pfu
Begin Time: 2025 Mar 31 1105 UTC
NOAA Scale: S1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Radio - Minor impacts on polar HF (high frequency) radio propagation resulting in fades at lower frequencies.

10:58 UTC

Space Weather Message Code: WARPX1
Serial Number: 597
Issue Time: 2025 Mar 31 1058 UTC

WARNING: Proton 10MeV Integral Flux above 10pfu expected
Valid From: 2025 Mar 31 1057 UTC
Valid To: 2025 Mar 31 2359 UTC
Warning Condition: Onset
Predicted NOAA Scale: S1 - Minor

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Radio - Minor impacts on polar HF (high frequency) radio propagation resulting in fades at lower frequencies.

05:02 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3442
Issue Time: 2025 Mar 31 0502 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3441
Begin Time: 2025 Mar 28 1410 UTC
Yesterday Maximum 2MeV Flux: 2772 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

Sunday, 30 March 2025

05:01 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3441
Issue Time: 2025 Mar 30 0501 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3440
Begin Time: 2025 Mar 28 1410 UTC
Yesterday Maximum 2MeV Flux: 2968 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

Saturday, 29 March 2025

05:07 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3440
Issue Time: 2025 Mar 29 0507 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3439
Begin Time: 2025 Mar 28 1410 UTC
Yesterday Maximum 2MeV Flux: 2819 pfu



Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

Friday, 28 March 2025

23:57 UTC

Space Weather Message Code: WARK04
Serial Number: 4894
Issue Time: 2025 Mar 28 2357 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4893
Valid From: 2025 Mar 25 2017 UTC
Now Valid Until: 2025 Mar 29 1200 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.