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, 11 May 2025
21:02 UTC
Space Weather Message Code: WARK05
Serial Number: 2041
Issue Time: 2025 May 11 2102 UTC
WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 May 11 2100 UTC
Valid To: 2025 May 12 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.
21:00 UTC
Space Weather Message Code: ALTK05
Serial Number: 1769
Issue Time: 2025 May 11 2100 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 11 2058 UTC
Synoptic Period: 1800-2100 UTC
Active Warning: No
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.
20:24 UTC
Space Weather Message Code: ALTK04
Serial Number: 2557
Issue Time: 2025 May 11 2024 UTC
ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 May 11 2021 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.
14:55 UTC
Space Weather Message Code: WARK04
Serial Number: 4961
Issue Time: 2025 May 11 1455 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4960
Valid From: 2025 May 11 0420 UTC
Now Valid Until: 2025 May 12 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.
04:20 UTC
Space Weather Message Code: WARK04
Serial Number: 4960
Issue Time: 2025 May 11 0420 UTC
WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 May 11 0420 UTC
Valid To: 2025 May 11 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.
Saturday, 10 May 2025
10:26 UTC
Space Weather Message Code: WARK05
Serial Number: 2040
Issue Time: 2025 May 10 1026 UTC
CANCEL WARNING: Geomagnetic K-index of 5 expected
Cancel Serial Number: 2039
Original Issue Time: 2025 May 09 2348 UTC
Comment: Geomagnetic K-index of 5 no longer expected.
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.
06:06 UTC
Space Weather Message Code: WARK04
Serial Number: 4959
Issue Time: 2025 May 10 0606 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4958
Valid From: 2025 May 09 1953 UTC
Now Valid Until: 2025 May 10 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.
05:59 UTC
Space Weather Message Code: WARK05
Serial Number: 2039
Issue Time: 2025 May 10 0559 UTC
EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2038
Valid From: 2025 May 09 2348 UTC
Now Valid Until: 2025 May 10 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.
Friday, 9 May 2025
23:48 UTC
Space Weather Message Code: WARK05
Serial Number: 2038
Issue Time: 2025 May 09 2348 UTC
WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 May 09 2348 UTC
Valid To: 2025 May 10 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.
19:57 UTC
Space Weather Message Code: ALTK04
Serial Number: 2556
Issue Time: 2025 May 09 1957 UTC
ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 May 09 1956 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.
19:56 UTC
Space Weather Message Code: WARK04
Serial Number: 4958
Issue Time: 2025 May 09 1956 UTC
WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 May 09 1953 UTC
Valid To: 2025 May 10 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.
06:42 UTC
Space Weather Message Code: ALTEF3
Serial Number: 3463
Issue Time: 2025 May 09 0642 UTC
CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3462
Begin Time: 2025 May 02 1330 UTC
Yesterday Maximum 2MeV Flux: 15854 pfu
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
Thursday, 8 May 2025
22:34 UTC
Space Weather Message Code: ALTK04
Serial Number: 2555
Issue Time: 2025 May 08 2234 UTC
ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 May 08 2234 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.
22:24 UTC
Space Weather Message Code: WARK04
Serial Number: 4957
Issue Time: 2025 May 08 2224 UTC
WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 May 08 2224 UTC
Valid To: 2025 May 09 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: 3462
Issue Time: 2025 May 08 0459 UTC
CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3461
Begin Time: 2025 May 02 1330 UTC
Yesterday Maximum 2MeV Flux: 12994 pfu
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
Wednesday, 7 May 2025
11:47 UTC
Space Weather Message Code: WATA20
Serial Number: 1039
Issue Time: 2025 May 07 1147 UTC
WATCH: Geomagnetic Storm Category G1 Predicted
Highest Storm Level Predicted by Day:
May 07: None (Below G1) May 08: None (Below G1) May 09: 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.
04:59 UTC
Space Weather Message Code: ALTEF3
Serial Number: 3461
Issue Time: 2025 May 07 0459 UTC
CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3460
Begin Time: 2025 May 02 1330 UTC
Yesterday Maximum 2MeV Flux: 11876 pfu
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
Tuesday, 6 May 2025
23:46 UTC
Space Weather Message Code: WARK04
Serial Number: 4956
Issue Time: 2025 May 06 2346 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4955
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 07 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.
14:52 UTC
Space Weather Message Code: WARK04
Serial Number: 4955
Issue Time: 2025 May 06 1452 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4954
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 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.
08:55 UTC
Space Weather Message Code: WARK04
Serial Number: 4954
Issue Time: 2025 May 06 0855 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4953
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 06 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.
05:00 UTC
Space Weather Message Code: ALTEF3
Serial Number: 3460
Issue Time: 2025 May 06 0500 UTC
CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3459
Begin Time: 2025 May 02 1330 UTC
Yesterday Maximum 2MeV Flux: 16255 pfu
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
Monday, 5 May 2025
23:48 UTC
Space Weather Message Code: WARK05
Serial Number: 2037
Issue Time: 2025 May 05 2348 UTC
EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2036
Valid From: 2025 May 04 2010 UTC
Now Valid Until: 2025 May 06 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.
18:06 UTC
Space Weather Message Code: WATA20
Serial Number: 1038
Issue Time: 2025 May 05 1806 UTC
WATCH: Geomagnetic Storm Category G1 Predicted
Highest Storm Level Predicted by Day:
May 06: G1 (Minor) May 07: None (Below G1) May 08: 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.
18:03 UTC
Space Weather Message Code: ALTK05
Serial Number: 1768
Issue Time: 2025 May 05 1803 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 05 1759 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.
14:38 UTC
Space Weather Message Code: WARK05
Serial Number: 2036
Issue Time: 2025 May 05 1438 UTC
EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2035
Valid From: 2025 May 04 2010 UTC
Now Valid Until: 2025 May 05 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.
14:30 UTC
Space Weather Message Code: WARK04
Serial Number: 4953
Issue Time: 2025 May 05 1430 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4952
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 06 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.
06:00 UTC
Space Weather Message Code: ALTK05
Serial Number: 1767
Issue Time: 2025 May 05 0600 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 05 0559 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.
05:55 UTC
Space Weather Message Code: WARK04
Serial Number: 4952
Issue Time: 2025 May 05 0555 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4951
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 05 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.
05:55 UTC
Space Weather Message Code: WARK05
Serial Number: 2035
Issue Time: 2025 May 05 0555 UTC
EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2034
Valid From: 2025 May 04 2010 UTC
Now Valid Until: 2025 May 05 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.
05:00 UTC
Space Weather Message Code: ALTEF3
Serial Number: 3459
Issue Time: 2025 May 05 0500 UTC
CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3458
Begin Time: 2025 May 02 1330 UTC
Yesterday Maximum 2MeV Flux: 9364 pfu
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
Sunday, 4 May 2025
20:11 UTC
Space Weather Message Code: WARK05
Serial Number: 2034
Issue Time: 2025 May 04 2011 UTC
WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 May 04 2010 UTC
Valid To: 2025 May 05 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.
18:58 UTC
Space Weather Message Code: WARK04
Serial Number: 4951
Issue Time: 2025 May 04 1858 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4950
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 05 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.
07:53 UTC
Space Weather Message Code: ALTK05
Serial Number: 1766
Issue Time: 2025 May 04 0753 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 04 0752 UTC
Synoptic Period: 0600-0900 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.
07:23 UTC
Space Weather Message Code: WARK04
Serial Number: 4950
Issue Time: 2025 May 04 0723 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4949
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 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.
07:23 UTC
Space Weather Message Code: WARK05
Serial Number: 2033
Issue Time: 2025 May 04 0723 UTC
WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 May 04 0722 UTC
Valid To: 2025 May 04 1500 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.
05:31 UTC
Space Weather Message Code: ALTEF3
Serial Number: 3458
Issue Time: 2025 May 04 0531 UTC
CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3457
Begin Time: 2025 May 02 1330 UTC
Yesterday Maximum 2MeV Flux: 5464 pfu
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
Saturday, 3 May 2025
17:27 UTC
Space Weather Message Code: WARK04
Serial Number: 4949
Issue Time: 2025 May 03 1727 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4948
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 04 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.
11:49 UTC
Space Weather Message Code: WARK05
Serial Number: 2032
Issue Time: 2025 May 03 1149 UTC
EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2031
Valid From: 2025 May 01 1350 UTC
Now Valid Until: 2025 May 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 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.
10:32 UTC
Space Weather Message Code: ALTK05
Serial Number: 1765
Issue Time: 2025 May 03 1032 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 03 1030 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.
06:51 UTC
Space Weather Message Code: ALTEF3
Serial Number: 3457
Issue Time: 2025 May 03 0651 UTC
CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3456
Begin Time: 2025 May 02 1330 UTC
Yesterday Maximum 2MeV Flux: 1451 pfu
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
01:29 UTC
Space Weather Message Code: WARK06
Serial Number: 579
Issue Time: 2025 May 03 0129 UTC
WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2025 May 03 0130 UTC
Valid To: 2025 May 03 0900 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.
01:29 UTC
Space Weather Message Code: WARK05
Serial Number: 2031
Issue Time: 2025 May 03 0129 UTC
EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2030
Valid From: 2025 May 01 1350 UTC
Now Valid Until: 2025 May 03 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.
01:29 UTC
Space Weather Message Code: WARK04
Serial Number: 4948
Issue Time: 2025 May 03 0129 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4947
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 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.
00:56 UTC
Space Weather Message Code: ALTK05
Serial Number: 1764
Issue Time: 2025 May 03 0056 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 03 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.
Friday, 2 May 2025
23:25 UTC
Space Weather Message Code: ALTK05
Serial Number: 1763
Issue Time: 2025 May 02 2325 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 02 2320 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.
18:02 UTC
Space Weather Message Code: ALTK05
Serial Number: 1762
Issue Time: 2025 May 02 1802 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 02 1759 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.
17:46 UTC
Space Weather Message Code: WARK04
Serial Number: 4947
Issue Time: 2025 May 02 1746 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4946
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 03 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.
17:41 UTC
Space Weather Message Code: WARK05
Serial Number: 2030
Issue Time: 2025 May 02 1741 UTC
EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2029
Valid From: 2025 May 01 1350 UTC
Now Valid Until: 2025 May 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 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.
14:40 UTC
Space Weather Message Code: ALTK05
Serial Number: 1761
Issue Time: 2025 May 02 1440 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 02 1435 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.
13:44 UTC
Space Weather Message Code: ALTEF3
Serial Number: 3456
Issue Time: 2025 May 02 1344 UTC
ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2025 May 02 1330 UTC
Station: GOES19
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
08:31 UTC
Space Weather Message Code: WARK05
Serial Number: 2029
Issue Time: 2025 May 02 0831 UTC
EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2028
Valid From: 2025 May 01 1350 UTC
Now Valid Until: 2025 May 02 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.
08:30 UTC
Space Weather Message Code: WARK04
Serial Number: 4946
Issue Time: 2025 May 02 0830 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4945
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 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.
05:07 UTC
Space Weather Message Code: ALTK05
Serial Number: 1760
Issue Time: 2025 May 02 0507 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 02 0459 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.
02:06 UTC
Space Weather Message Code: WARK06
Serial Number: 578
Issue Time: 2025 May 02 0206 UTC
WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2025 May 02 0206 UTC
Valid To: 2025 May 02 0900 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.
01:55 UTC
Space Weather Message Code: ALTK05
Serial Number: 1759
Issue Time: 2025 May 02 0155 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 02 0155 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.
Thursday, 1 May 2025
23:53 UTC
Space Weather Message Code: WARK04
Serial Number: 4945
Issue Time: 2025 May 01 2353 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4944
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 02 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.
23:48 UTC
Space Weather Message Code: WARK05
Serial Number: 2028
Issue Time: 2025 May 01 2348 UTC
EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2027
Valid From: 2025 May 01 1350 UTC
Now Valid Until: 2025 May 02 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.
23:40 UTC
Space Weather Message Code: ALTK05
Serial Number: 1758
Issue Time: 2025 May 01 2340 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 01 2339 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.
20:23 UTC
Space Weather Message Code: ALTK05
Serial Number: 1757
Issue Time: 2025 May 01 2023 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2025 May 01 2022 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.
17:50 UTC
Space Weather Message Code: WATA20
Serial Number: 1037
Issue Time: 2025 May 01 1750 UTC
WATCH: Geomagnetic Storm Category G1 Predicted
Highest Storm Level Predicted by Day:
May 02: G1 (Minor) May 03: None (Below G1) May 04: 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.
13:52 UTC
Space Weather Message Code: WARK04
Serial Number: 4944
Issue Time: 2025 May 01 1352 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4943
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 02 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.
13:52 UTC
Space Weather Message Code: WARK05
Serial Number: 2027
Issue Time: 2025 May 01 1352 UTC
WARNING: Geomagnetic K-index of 5 expected
Valid From: 2025 May 01 1350 UTC
Valid To: 2025 May 01 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.
10:40 UTC
Space Weather Message Code: WARK04
Serial Number: 4943
Issue Time: 2025 May 01 1040 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4942
Valid From: 2025 May 01 0343 UTC
Now Valid Until: 2025 May 01 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.
05:38 UTC
Space Weather Message Code: ALTK04
Serial Number: 2554
Issue Time: 2025 May 01 0538 UTC
ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 May 01 0532 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.
03:43 UTC
Space Weather Message Code: WARK04
Serial Number: 4942
Issue Time: 2025 May 01 0343 UTC
WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 May 01 0343 UTC
Valid To: 2025 May 01 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.
Wednesday, 30 April 2025
11:30 UTC
Space Weather Message Code: WARK04
Serial Number: 4941
Issue Time: 2025 Apr 30 1130 UTC
EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 4940
Valid From: 2025 Apr 30 0225 UTC
Now Valid Until: 2025 Apr 30 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.
03:00 UTC
Space Weather Message Code: ALTK04
Serial Number: 2553
Issue Time: 2025 Apr 30 0300 UTC
ALERT: Geomagnetic K-index of 4
Threshold Reached: 2025 Apr 30 0259 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.
02:25 UTC
Space Weather Message Code: WARK04
Serial Number: 4940
Issue Time: 2025 Apr 30 0225 UTC
WARNING: Geomagnetic K-index of 4 expected
Valid From: 2025 Apr 30 0225 UTC
Valid To: 2025 Apr 30 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.
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.
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| Last X-flare | 2025/03/28 | X1.1 |
| Last M-flare | 2025/05/12 | M1.9 |
| Last geomagnetic storm | 2025/05/03 | Kp5 (G1) |
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