Local 4/21/2026, 1:41:49 PM
UTC 2026-04-21T13:41:49.383Z
Space Weather Message Code: ALTEF3Serial Number: 3681Issue Time: 2026 Apr 21 1341 UTCCONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfuContinuation of Serial Number: 3680Begin Time: 2026 Apr 19 1920 UTCYesterday Maximum 2MeV Flux: 1344 pfuPotential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
Local 4/21/2026, 5:45:40 AM
UTC 2026-04-21T05:45:40.253Z
Space Weather Message Code: WARK04Serial Number: 5325Issue Time: 2026 Apr 21 0545 UTCEXTENDED WARNING: Geomagnetic K-index of 4 expectedExtension to Serial Number: 5324Valid From: 2026 Apr 20 0805 UTCNow Valid Until: 2026 Apr 21 1800 UTCWarning Condition: PersistenceNOAA Space Weather Scale descriptions can be found atwww.swpc.noaa.gov/noaa-scales-explanationPotential 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.
Local 4/21/2026, 5:44:46 AM
UTC 2026-04-21T05:44:46.137Z
Space Weather Message Code: WARK05Serial Number: 2229Issue Time: 2026 Apr 21 0544 UTCEXTENDED WARNING: Geomagnetic K-index of 5 expectedExtension to Serial Number: 2228Valid From: 2026 Apr 21 0110 UTCNow Valid Until: 2026 Apr 21 1500 UTCWarning Condition: PersistenceNOAA Space Weather Scale descriptions can be found atwww.swpc.noaa.gov/noaa-scales-explanationPotential 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.
Local 4/21/2026, 1:53:51 AM
UTC 2026-04-21T01:53:51.080Z
Space Weather Message Code: ALTK05Serial Number: 2012Issue Time: 2026 Apr 21 0153 UTCALERT: Geomagnetic K-index of 5Threshold Reached: 2026 Apr 21 0148 UTCSynoptic Period: 0000-0300 UTCActive Warning: YesNOAA Scale: G1 - MinorNOAA Space Weather Scale descriptions can be found atwww.swpc.noaa.gov/noaa-scales-explanationPotential 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.
Local 4/21/2026, 1:10:21 AM
UTC 2026-04-21T01:10:21.750Z
Space Weather Message Code: WARK04Serial Number: 5324Issue Time: 2026 Apr 21 0110 UTCEXTENDED WARNING: Geomagnetic K-index of 4 expectedExtension to Serial Number: 5323Valid From: 2026 Apr 20 0805 UTCNow Valid Until: 2026 Apr 21 1200 UTCWarning Condition: PersistenceNOAA Space Weather Scale descriptions can be found atwww.swpc.noaa.gov/noaa-scales-explanationPotential 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.
Local 4/21/2026, 1:10:21 AM
UTC 2026-04-21T01:10:21.733Z
Space Weather Message Code: WARK05Serial Number: 2228Issue Time: 2026 Apr 21 0110 UTCWARNING: Geomagnetic K-index of 5 expectedValid From: 2026 Apr 21 0110 UTCValid To: 2026 Apr 21 0600 UTCWarning Condition: PersistenceNOAA Scale: G1 - MinorNOAA Space Weather Scale descriptions can be found atwww.swpc.noaa.gov/noaa-scales-explanationPotential 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.
Local 4/20/2026, 8:23:35 PM
UTC 2026-04-20T20:23:35.100Z
Space Weather Message Code: ALTEF3Serial Number: 3680Issue Time: 2026 Apr 20 2023 UTCCONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfuContinuation of Serial Number: 3679Begin Time: 2026 Apr 19 1920 UTCYesterday Maximum 2MeV Flux: 1297 pfuPotential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
Local 4/20/2026, 7:34:54 PM
UTC 2026-04-20T19:34:54.467Z
Space Weather Message Code: ALTK05 Serial Number: 1783 Issue Time: 2026-04-20T19:34:00 ALERT: Geomagnetic K-index of 5 THRESHOLD: 2026-04-20 19:34 UTC ISSUED BY: Forecaster User SYNOPTIC PERIOD: 1800-2100 ACTIVE WARNING: YES NOAA SCALE: G1 - Minor COMMENT: G1 - Minor
Local 4/20/2026, 5:36:08 PM
UTC 2026-04-20T17:36:08.423Z
Space Weather Message Code: ALTK05 Serial Number: 1782 Issue Time: 2026-04-20T17:36:00 ALERT: Geomagnetic K-index of 5 THRESHOLD: 2026-04-20 17:34 UTC ISSUED BY: Forecaster User SYNOPTIC PERIOD: 1500-1800 ACTIVE WARNING: YES NOAA SCALE: G1 - Minor COMMENT: G1 - Minor
Local 4/20/2026, 5:21:37 PM
UTC 2026-04-20T17:21:37.853Z
Space Weather Message Code: WARK04 Serial Number: 5001 Issue Time: 2026-04-20T17:21:00 EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 5323 Valid From: 2026-04-20T08:05:00 Now Valid Until: 2026-04-21 03:00 Warning Condition: Persistence Extended 2026-04-20 17:21 by Forecaster User Extended 2026-04-20 17:21 by Forecaster User
Local 4/20/2026, 5:20:34 PM
UTC 2026-04-20T17:20:34.170Z
Space Weather Message Code: WARK05 Serial Number: 2065 Issue Time: 2026-04-20T17:20:00 WARNING: Geomagnetic K-index of 5 expected ISSUED BY: Forecaster User VALID FROM: 2026-04-20 17:20 UTC VALID TO: 2026-04-20 23:59 UTC WARNING CONDITIONS: Onset NOAA SCALE: G1 - Minor COMMENT: G1 - Minor
Local 4/20/2026, 2:20:35 PM
UTC 2026-04-20T14:20:35.673Z
Space Weather Message Code: WARK04Serial Number: 5323Issue Time: 2026 Apr 20 1420 UTCEXTENDED WARNING: Geomagnetic K-index of 4 expectedExtension to Serial Number: 5322Valid From: 2026 Apr 20 0805 UTCNow Valid Until: 2026 Apr 20 2100 UTCWarning Condition: OnsetNOAA Space Weather Scale descriptions can be found atwww.swpc.noaa.gov/noaa-scales-explanationPotential 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.
Local 4/20/2026, 8:19:55 AM
UTC 2026-04-20T08:19:55.567Z
Space Weather Message Code: ALTK04Serial Number: 2651Issue Time: 2026 Apr 20 0819 UTCALERT: Geomagnetic K-index of 4Threshold Reached: 2026 Apr 20 0820 UTCSynoptic Period: 0600-0900 UTCActive Warning: YesNOAA Space Weather Scale descriptions can be found atwww.swpc.noaa.gov/noaa-scales-explanationPotential 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.
Local 4/20/2026, 8:05:35 AM
UTC 2026-04-20T08:05:35.553Z
Space Weather Message Code: WARK04Serial Number: 5322Issue Time: 2026 Apr 20 0805 UTCWARNING: Geomagnetic K-index of 4 expectedValid From: 2026 Apr 20 0805 UTCValid To: 2026 Apr 20 1500 UTCWarning Condition: OnsetNOAA Space Weather Scale descriptions can be found atwww.swpc.noaa.gov/noaa-scales-explanationPotential 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.
Local 4/19/2026, 7:47:15 PM
UTC 2026-04-19T19:47:15.250Z
Space Weather Message Code: ALTEF3Serial Number: 3679Issue Time: 2026 Apr 19 1947 UTCALERT: Electron 2MeV Integral Flux exceeded 1000pfuThreshold Reached: 2026 Apr 19 1920 UTCStation: GOES19Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.