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.

Saturday, 2 May 2026

11:11 UTC

Space Weather Message Code: ALTTP2
Serial Number: 1482
Issue Time: 2026 May 02 1111 UTC

ALERT: Type II Radio Emission
Begin Time: 2026 May 02 1051 UTC
Estimated Velocity: 641 km/s

Comment: Likely associated with C-class flare acitivity originating from AR 4420 on the west limb.



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, 1 May 2026

15:50 UTC

Space Weather Message Code: ALTTP2
Serial Number: 1481
Issue Time: 2026 May 01 1550 UTC

ALERT: Type II Radio Emission
Begin Time: 2026 May 01 1535 UTC
Estimated Velocity: 593 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.

Thursday, 30 April 2026

23:59 UTC

Space Weather Message Code: ALTK05
Serial Number: 2013
Issue Time: 2026 Apr 30 2359 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 30 2359 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.

23:11 UTC

Space Weather Message Code: WARK04
Serial Number: 5332
Issue Time: 2026 Apr 30 2311 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5331
Valid From: 2026 Apr 30 2005 UTC
Now Valid Until: 2026 May 01 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.

23:09 UTC

Space Weather Message Code: WARK05
Serial Number: 2230
Issue Time: 2026 Apr 30 2309 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2026 Apr 30 2309 UTC
Valid To: 2026 May 01 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.

20:35 UTC

Space Weather Message Code: ALTK04
Serial Number: 2653
Issue Time: 2026 Apr 30 2035 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2026 Apr 30 2035 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes

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

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

20:06 UTC

Space Weather Message Code: WARK04
Serial Number: 5331
Issue Time: 2026 Apr 30 2006 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2026 Apr 30 2005 UTC
Valid To: 2026 May 01 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.

Monday, 27 April 2026

01:06 UTC

Space Weather Message Code: ALTTP2
Serial Number: 1480
Issue Time: 2026 Apr 27 0106 UTC

ALERT: Type II Radio Emission
Begin Time: 2026 Apr 26 2257 UTC
Estimated Velocity: 834 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.

Sunday, 26 April 2026

23:33 UTC

Space Weather Message Code: WARK04
Serial Number: 5330
Issue Time: 2026 Apr 26 2333 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5329
Valid From: 2026 Apr 26 0359 UTC
Now Valid Until: 2026 Apr 27 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.

23:17 UTC

Space Weather Message Code: SUMXM5
Serial Number: 314
Issue Time: 2026 Apr 26 2317 UTC

SUMMARY: X-ray Event exceeded M5
Begin Time: 2026 Apr 26 2251 UTC
Maximum Time: 2026 Apr 26 2257 UTC
End Time: 2026 Apr 26 2302 UTC
X-ray Class: M6.0
Location: N21W33
NOAA Scale: R2 - Moderate

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

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

23:08 UTC

Space Weather Message Code: SUM10R
Serial Number: 909
Issue Time: 2026 Apr 26 2308 UTC

SUMMARY: 10cm Radio Burst
Begin Time: 2026 Apr 26 2256 UTC
Maximum Time: 2026 Apr 26 2257 UTC
End Time: 2026 Apr 26 2258 UTC
Duration: 1 minutes
Peak Flux: 260 sfu
Latest Penticton Noon Flux: 148 sfu



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

23:00 UTC

Space Weather Message Code: ALTXMF
Serial Number: 526
Issue Time: 2026 Apr 26 2300 UTC

ALERT: X-Ray Flux exceeded M5
Threshold Reached: 2026 Apr 26 2257 UTC
NOAA Scale: R2 - Moderate

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

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

11:47 UTC

Space Weather Message Code: WARK04
Serial Number: 5329
Issue Time: 2026 Apr 26 1147 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5328
Valid From: 2026 Apr 26 0359 UTC
Now Valid Until: 2026 Apr 26 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.

06:01 UTC

Space Weather Message Code: WARK04
Serial Number: 5328
Issue Time: 2026 Apr 26 0601 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2026 Apr 26 0359 UTC
Valid To: 2026 Apr 26 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.

05:59 UTC

Space Weather Message Code: ALTK04
Serial Number: 2652
Issue Time: 2026 Apr 26 0559 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2026 Apr 26 0559 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.

Saturday, 25 April 2026

01:37 UTC

Space Weather Message Code: WARK04
Serial Number: 5327
Issue Time: 2026 Apr 25 0137 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2026 Apr 25 0137 UTC
Valid To: 2026 Apr 25 2359 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.

Friday, 24 April 2026

23:50 UTC

Space Weather Message Code: WATA20
Serial Number: 1109
Issue Time: 2026 Apr 24 2350 UTC

WATCH: Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
Apr 25: G1 (Minor) Apr 26: G1 (Minor) Apr 27: 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.

18:35 UTC

Space Weather Message Code: SUMXM5
Serial Number: 313
Issue Time: 2026 Apr 24 1835 UTC

SUMMARY: X-ray Event exceeded M5
Begin Time: 2026 Apr 24 1754 UTC
Maximum Time: 2026 Apr 24 1815 UTC
End Time: 2026 Apr 24 1830 UTC
X-ray Class: M6.4
Location: N19W90
NOAA Scale: R2 - Moderate

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

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

18:12 UTC

Space Weather Message Code: ALTXMF
Serial Number: 525
Issue Time: 2026 Apr 24 1812 UTC

ALERT: X-Ray Flux exceeded M5
Threshold Reached: 2026 Apr 24 1812 UTC
NOAA Scale: R2 - Moderate

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

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

10:42 UTC

Space Weather Message Code: ALTTP4
Serial Number: 707
Issue Time: 2026 Apr 24 1041 UTC

ALERT: Type IV Radio Emission
Begin Time: 2026 Apr 24 0840 UTC



Description: Type IV emissions occur in association with major eruptions on the sun and are typically associated with strong coronal mass ejections and solar radiation storms.

09:28 UTC

Space Weather Message Code: ALTTP2
Serial Number: 1479
Issue Time: 2026 Apr 24 0928 UTC

ALERT: Type II Radio Emission
Begin Time: 2026 Apr 24 0815 UTC
Estimated Velocity: 1293 km/s

Comment: Reissued with adjusted shock speed.



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.

09:27 UTC

Space Weather Message Code: ALTTP2
Serial Number: 1478
Issue Time: 2026 Apr 24 0927 UTC

CANCEL ALERT: Type II Radio Emission
Cancel Serial Number: 1477
Original Issue Time: 2026 Apr 24 0857 UTC

Comment: Reissuing with corrected shock speed.



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.

08:57 UTC

Space Weather Message Code: ALTTP2
Serial Number: 1477
Issue Time: 2026 Apr 24 0857 UTC

ALERT: Type II Radio Emission
Begin Time: 2026 Apr 24 0815 UTC
Estimated Velocity: 1869 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.

08:38 UTC

Space Weather Message Code: SUM10R
Serial Number: 908
Issue Time: 2026 Apr 24 0838 UTC

SUMMARY: 10cm Radio Burst
Begin Time: 2026 Apr 24 0809 UTC
Maximum Time: 2026 Apr 24 0811 UTC
End Time: 2026 Apr 24 0815 UTC
Duration: 6 minutes
Peak Flux: 570 sfu
Latest Penticton Noon Flux: 128 sfu



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

08:26 UTC

Space Weather Message Code: SUMX01
Serial Number: 216
Issue Time: 2026 Apr 24 0826 UTC

SUMMARY: X-ray Event exceeded X1
Begin Time: 2026 Apr 24 0801 UTC
Maximum Time: 2026 Apr 24 0813 UTC
End Time: 2026 Apr 24 0818 UTC
X-ray Class: X2.5
Optical Class: 2b
Location: N20W90
NOAA Scale: R3 - Strong

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

Potential Impacts: Area of impact consists of large portions of the sunlit side of Earth, strongest at the sub-solar point.
Radio - Wide area blackout of HF (high frequency) radio communication for about an hour.

08:12 UTC

Space Weather Message Code: ALTXMF
Serial Number: 524
Issue Time: 2026 Apr 24 0812 UTC

ALERT: X-Ray Flux exceeded M5
Threshold Reached: 2026 Apr 24 0812 UTC
NOAA Scale: R2 - Moderate

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

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

05:05 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3684
Issue Time: 2026 Apr 24 0505 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3683
Begin Time: 2026 Apr 19 1920 UTC
Yesterday Maximum 2MeV Flux: 3446 pfu



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

01:31 UTC

Space Weather Message Code: SUMX01
Serial Number: 215
Issue Time: 2026 Apr 24 0131 UTC

SUMMARY: X-ray Event exceeded X1
Begin Time: 2026 Apr 24 0051 UTC
Maximum Time: 2026 Apr 24 0107 UTC
End Time: 2026 Apr 24 0113 UTC
X-ray Class: X2.4
Location: N17W71
NOAA Scale: R3 - Strong

Comment: Accompanied by a tenflare with a castelli-U signature. No radio observations currently available.

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

Potential Impacts: Area of impact consists of large portions of the sunlit side of Earth, strongest at the sub-solar point.
Radio - Wide area blackout of HF (high frequency) radio communication for about an hour.

01:29 UTC

Space Weather Message Code: SUM10R
Serial Number: 907
Issue Time: 2026 Apr 24 0129 UTC

SUMMARY: 10cm Radio Burst
Begin Time: 2026 Apr 24 0103 UTC
Maximum Time: 2026 Apr 24 0104 UTC
End Time: 2026 Apr 24 0109 UTC
Duration: 6 minutes
Peak Flux: 570 sfu
Latest Penticton Noon Flux: 128 sfu



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

01:08 UTC

Space Weather Message Code: ALTXMF
Serial Number: 523
Issue Time: 2026 Apr 24 0108 UTC

ALERT: X-Ray Flux exceeded M5
Threshold Reached: 2026 Apr 24 0105 UTC
NOAA Scale: R2 - Moderate

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

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

Thursday, 23 April 2026

17:23 UTC

Space Weather Message Code: SUM10R
Serial Number: 906
Issue Time: 2026 Apr 23 1723 UTC

SUMMARY: 10cm Radio Burst
Begin Time: 2026 Apr 23 1703 UTC
Maximum Time: 2026 Apr 23 1705 UTC
End Time: 2026 Apr 23 1707 UTC
Duration: 4 minutes
Peak Flux: 220 sfu
Latest Penticton Noon Flux: 116 sfu



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

14:52 UTC

Space Weather Message Code: SUM10R
Serial Number: 905
Issue Time: 2026 Apr 23 1452 UTC

SUMMARY: 10cm Radio Burst
Begin Time: 2026 Apr 23 1355 UTC
Maximum Time: 2026 Apr 23 1356 UTC
End Time: 2026 Apr 23 1357 UTC
Duration: 2 minutes
Peak Flux: 170 sfu
Latest Penticton Noon Flux: 116 sfu



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

09:14 UTC

Space Weather Message Code: ALTTP2
Serial Number: 1476
Issue Time: 2026 Apr 23 0914 UTC

ALERT: Type II Radio Emission
Begin Time: 2026 Apr 23 0859 UTC
Estimated Velocity: 722 km/s

Comment: Report from San Vito



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.

08:59 UTC

Space Weather Message Code: SUM10R
Serial Number: 904
Issue Time: 2026 Apr 23 0859 UTC

SUMMARY: 10cm Radio Burst
Begin Time: 2026 Apr 23 0844 UTC
Maximum Time: 2026 Apr 23 0844 UTC
End Time: 2026 Apr 23 0844 UTC
Duration: 1 minutes
Peak Flux: 130 sfu
Latest Penticton Noon Flux: 116 sfu



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

05:35 UTC

Space Weather Message Code: ALTTP4
Serial Number: 706
Issue Time: 2026 Apr 23 0535 UTC

ALERT: Type IV Radio Emission
Begin Time: 2026 Apr 23 0513 UTC

Comment: Report from San Vito



Description: Type IV emissions occur in association with major eruptions on the sun and are typically associated with strong coronal mass ejections and solar radiation storms.

05:10 UTC

Space Weather Message Code: ALTTP2
Serial Number: 1475
Issue Time: 2026 Apr 23 0510 UTC

ALERT: Type II Radio Emission
Begin Time: 2026 Apr 23 0450 UTC
Estimated Velocity: 1033 km/s

Comment: Report from San Vito



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.

04:59 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3683
Issue Time: 2026 Apr 23 0459 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3682
Begin Time: 2026 Apr 19 1920 UTC
Yesterday Maximum 2MeV Flux: 4922 pfu



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

Wednesday, 22 April 2026

05:03 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3682
Issue Time: 2026 Apr 22 0503 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3681
Begin Time: 2026 Apr 19 1920 UTC
Yesterday Maximum 2MeV Flux: 4987 pfu



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

Tuesday, 21 April 2026

16:51 UTC

Space Weather Message Code: WARK04
Serial Number: 5326
Issue Time: 2026 Apr 21 1651 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5325
Valid From: 2026 Apr 20 0805 UTC
Now Valid Until: 2026 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.

13:41 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3681
Issue Time: 2026 Apr 21 1341 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3680
Begin Time: 2026 Apr 19 1920 UTC
Yesterday Maximum 2MeV Flux: 1344 pfu



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

05:45 UTC

Space Weather Message Code: WARK04
Serial Number: 5325
Issue Time: 2026 Apr 21 0545 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5324
Valid From: 2026 Apr 20 0805 UTC
Now Valid Until: 2026 Apr 21 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.

05:44 UTC

Space Weather Message Code: WARK05
Serial Number: 2229
Issue Time: 2026 Apr 21 0544 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2228
Valid From: 2026 Apr 21 0110 UTC
Now Valid Until: 2026 Apr 21 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.

01:53 UTC

Space Weather Message Code: ALTK05
Serial Number: 2012
Issue Time: 2026 Apr 21 0153 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 21 0148 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.

01:10 UTC

Space Weather Message Code: WARK04
Serial Number: 5324
Issue Time: 2026 Apr 21 0110 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5323
Valid From: 2026 Apr 20 0805 UTC
Now Valid Until: 2026 Apr 21 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.

01:10 UTC

Space Weather Message Code: WARK05
Serial Number: 2228
Issue Time: 2026 Apr 21 0110 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2026 Apr 21 0110 UTC
Valid To: 2026 Apr 21 0600 UTC
Warning Condition: Persistence
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.

Monday, 20 April 2026

20:23 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3680
Issue Time: 2026 Apr 20 2023 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3679
Begin Time: 2026 Apr 19 1920 UTC
Yesterday Maximum 2MeV Flux: 1297 pfu



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

19:34 UTC

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

17:36 UTC

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

17:21 UTC

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

17:20 UTC

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

14:20 UTC

Space Weather Message Code: WARK04
Serial Number: 5323
Issue Time: 2026 Apr 20 1420 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5322
Valid From: 2026 Apr 20 0805 UTC
Now Valid Until: 2026 Apr 20 2100 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.

08:19 UTC

Space Weather Message Code: ALTK04
Serial Number: 2651
Issue Time: 2026 Apr 20 0819 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2026 Apr 20 0820 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.

08:05 UTC

Space Weather Message Code: WARK04
Serial Number: 5322
Issue Time: 2026 Apr 20 0805 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2026 Apr 20 0805 UTC
Valid To: 2026 Apr 20 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.

Sunday, 19 April 2026

19:47 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3679
Issue Time: 2026 Apr 19 1947 UTC

ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2026 Apr 19 1920 UTC
Station: GOES19




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

09:00 UTC

Space Weather Message Code: ALTK06
Serial Number: 714
Issue Time: 2026 Apr 19 0900 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2026 Apr 19 0859 UTC
Synoptic Period: 0600-0900 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.

08:49 UTC

Space Weather Message Code: WARK05
Serial Number: 2227
Issue Time: 2026 Apr 19 0849 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2226
Valid From: 2026 Apr 18 2348 UTC
Now Valid Until: 2026 Apr 19 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.

08:49 UTC

Space Weather Message Code: WARK06
Serial Number: 655
Issue Time: 2026 Apr 19 0849 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2026 Apr 19 0848 UTC
Valid To: 2026 Apr 19 1500 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.

08:49 UTC

Space Weather Message Code: WARK04
Serial Number: 5321
Issue Time: 2026 Apr 19 0849 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5320
Valid From: 2026 Apr 18 0157 UTC
Now Valid Until: 2026 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.

06:50 UTC

Space Weather Message Code: ALTK05
Serial Number: 2011
Issue Time: 2026 Apr 19 0650 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 19 0650 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.

06:04 UTC

Space Weather Message Code: ALTK05
Serial Number: 2010
Issue Time: 2026 Apr 19 0604 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 19 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.

06:04 UTC

Space Weather Message Code: WARK05
Serial Number: 2226
Issue Time: 2026 Apr 19 0604 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2225
Valid From: 2026 Apr 18 2348 UTC
Now Valid Until: 2026 Apr 19 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.

06:04 UTC

Space Weather Message Code: WARK04
Serial Number: 5320
Issue Time: 2026 Apr 19 0604 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5319
Valid From: 2026 Apr 18 0157 UTC
Now Valid Until: 2026 Apr 19 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.

Saturday, 18 April 2026

23:50 UTC

Space Weather Message Code: WARK05
Serial Number: 2225
Issue Time: 2026 Apr 18 2350 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2026 Apr 18 2348 UTC
Valid To: 2026 Apr 19 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.

22:46 UTC

Space Weather Message Code: WARK04
Serial Number: 5319
Issue Time: 2026 Apr 18 2246 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5318
Valid From: 2026 Apr 18 0157 UTC
Now Valid Until: 2026 Apr 19 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.

11:24 UTC

Space Weather Message Code: ALTK05
Serial Number: 2009
Issue Time: 2026 Apr 18 1124 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 18 1124 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.

08:25 UTC

Space Weather Message Code: ALTK06
Serial Number: 713
Issue Time: 2026 Apr 18 0825 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2026 Apr 18 0825 UTC
Synoptic Period: 0600-0900 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.

07:52 UTC

Space Weather Message Code: WARK06
Serial Number: 654
Issue Time: 2026 Apr 18 0752 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2026 Apr 18 0751 UTC
Valid To: 2026 Apr 18 1500 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.

07:41 UTC

Space Weather Message Code: ALTK05
Serial Number: 2008
Issue Time: 2026 Apr 18 0741 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 18 0740 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.

05:28 UTC

Space Weather Message Code: ALTK05
Serial Number: 2007
Issue Time: 2026 Apr 18 0528 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 18 0525 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.

04:14 UTC

Space Weather Message Code: ALTK04
Serial Number: 2650
Issue Time: 2026 Apr 18 0414 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2026 Apr 18 0414 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.

03:17 UTC

Space Weather Message Code: WARK05
Serial Number: 2224
Issue Time: 2026 Apr 18 0317 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2026 Apr 18 0317 UTC
Valid To: 2026 Apr 18 1800 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

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

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

01:58 UTC

Space Weather Message Code: WARK04
Serial Number: 5318
Issue Time: 2026 Apr 18 0158 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2026 Apr 18 0157 UTC
Valid To: 2026 Apr 18 2359 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.

Friday, 17 April 2026

07:31 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3678
Issue Time: 2026 Apr 17 0731 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3677
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 2407 pfu



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

Thursday, 16 April 2026

22:09 UTC

Space Weather Message Code: WATA20
Serial Number: 1108
Issue Time: 2026 Apr 16 2209 UTC

WATCH: Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
Apr 17: G2 (Moderate) Apr 18: G2 (Moderate) Apr 19: 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.

13:23 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3677
Issue Time: 2026 Apr 16 1323 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3676
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 3248 pfu



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

Wednesday, 15 April 2026

21:43 UTC

Space Weather Message Code: WATA30
Serial Number: 271
Issue Time: 2026 Apr 15 2143 UTC

WATCH: Geomagnetic Storm Category G2 Predicted

Highest Storm Level Predicted by Day:
Apr 16: None (Below G1) Apr 17: G2 (Moderate) Apr 18: 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.

07:56 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3676
Issue Time: 2026 Apr 15 0756 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3675
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 1705 pfu



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

Tuesday, 14 April 2026

11:37 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3675
Issue Time: 2026 Apr 14 1137 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3674
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 1650 pfu



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

Monday, 13 April 2026

11:01 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3674
Issue Time: 2026 Apr 13 1101 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3673
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 1610 pfu



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

Sunday, 12 April 2026

13:17 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3673
Issue Time: 2026 Apr 12 1317 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3672
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 1082 pfu



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

09:45 UTC

Space Weather Message Code: WARK04
Serial Number: 5317
Issue Time: 2026 Apr 12 0945 UTC

CANCEL WARNING: Geomagnetic K-index of 4 expected
Cancel Serial Number: 5316
Original Issue Time: 2026 Apr 10 0143 UTC

Comment: Active conditions (Kp=4) are no longer expected to occur.

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, 11 April 2026

17:56 UTC

Space Weather Message Code: WARK04
Serial Number: 5316
Issue Time: 2026 Apr 11 1756 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5315
Valid From: 2026 Apr 10 0145 UTC
Now Valid Until: 2026 Apr 12 1500 UTC
Warning Condition: Persistence

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

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

13:06 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3672
Issue Time: 2026 Apr 11 1306 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3671
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 1714 pfu



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

Friday, 10 April 2026

14:26 UTC

Space Weather Message Code: WARK05
Serial Number: 2223
Issue Time: 2026 Apr 10 1426 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2026 Apr 10 1425 UTC
Valid To: 2026 Apr 11 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.

14:07 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3671
Issue Time: 2026 Apr 10 1407 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3670
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 10680 pfu



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

13:50 UTC

Space Weather Message Code: WARK04
Serial Number: 5315
Issue Time: 2026 Apr 10 1350 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5314
Valid From: 2026 Apr 10 0145 UTC
Now Valid Until: 2026 Apr 11 1800 UTC
Warning Condition: Persistence

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

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

02:08 UTC

Space Weather Message Code: ALTK04
Serial Number: 2649
Issue Time: 2026 Apr 10 0208 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2026 Apr 10 0205 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes

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

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

01:43 UTC

Space Weather Message Code: WARK04
Serial Number: 5314
Issue Time: 2026 Apr 10 0143 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2026 Apr 10 0145 UTC
Valid To: 2026 Apr 10 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.

Thursday, 9 April 2026

04:59 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3670
Issue Time: 2026 Apr 09 0459 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3669
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 7322 pfu



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

Wednesday, 8 April 2026

04:59 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3669
Issue Time: 2026 Apr 08 0459 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3668
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 7359 pfu



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

02:29 UTC

Space Weather Message Code: WATA20
Serial Number: 1107
Issue Time: 2026 Apr 08 0229 UTC

WATCH: Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
Apr 09: None (Below G1) Apr 10: G1 (Minor) Apr 11: G1 (Minor)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

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

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

Tuesday, 7 April 2026

05:00 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3668
Issue Time: 2026 Apr 07 0500 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3667
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 6075 pfu



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

01:24 UTC

Space Weather Message Code: WARK04
Serial Number: 5313
Issue Time: 2026 Apr 07 0124 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2026 Apr 07 0124 UTC
Valid To: 2026 Apr 07 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, 6 April 2026

04:59 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3667
Issue Time: 2026 Apr 06 0459 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3666
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 5995 pfu



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

Sunday, 5 April 2026

05:07 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3666
Issue Time: 2026 Apr 05 0507 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3665
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 2419 pfu



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

02:48 UTC

Space Weather Message Code: WARK04
Serial Number: 5312
Issue Time: 2026 Apr 05 0248 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5311
Valid From: 2026 Apr 02 0047 UTC
Now Valid Until: 2026 Apr 05 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.

Saturday, 4 April 2026

23:56 UTC

Space Weather Message Code: WARK04
Serial Number: 5311
Issue Time: 2026 Apr 04 2356 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5310
Valid From: 2026 Apr 02 0047 UTC
Now Valid Until: 2026 Apr 05 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 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.

11:58 UTC

Space Weather Message Code: ALTEF3
Serial Number: 3665
Issue Time: 2026 Apr 04 1158 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 3664
Begin Time: 2026 Apr 03 0920 UTC
Yesterday Maximum 2MeV Flux: 4465 pfu



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

02:54 UTC

Space Weather Message Code: ALTK05
Serial Number: 2006
Issue Time: 2026 Apr 04 0254 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 04 0248 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.

01:46 UTC

Space Weather Message Code: SUMXM5
Serial Number: 312
Issue Time: 2026 Apr 04 0146 UTC

SUMMARY: X-ray Event exceeded M5
Begin Time: 2026 Apr 04 0107 UTC
Maximum Time: 2026 Apr 04 0117 UTC
End Time: 2026 Apr 04 0123 UTC
X-ray Class: M7.5
Location: N04W04
NOAA Scale: R2 - Moderate

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

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

01:17 UTC

Space Weather Message Code: ALTXMF
Serial Number: 522
Issue Time: 2026 Apr 04 0117 UTC

ALERT: X-Ray Flux exceeded M5
Threshold Reached: 2026 Apr 04 0117 UTC
NOAA Scale: R2 - Moderate

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

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

Friday, 3 April 2026

23:10 UTC

Space Weather Message Code: WARK06
Serial Number: 653
Issue Time: 2026 Apr 03 2310 UTC

EXTENDED WARNING: Geomagnetic K-Index of 6 expected
Extension to Serial Number: 652
Valid From: 2026 Apr 03 1551 UTC
Now Valid Until: 2026 Apr 04 0600 UTC
Warning Condition: Persistence

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

Potential Impacts: Area of impact primarily poleward of 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.

23:10 UTC

Space Weather Message Code: ALTK06
Serial Number: 712
Issue Time: 2026 Apr 03 2310 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2026 Apr 03 2303 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.

21:41 UTC

Space Weather Message Code: ALTK05
Serial Number: 2005
Issue Time: 2026 Apr 03 2141 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 03 2140 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.

21:02 UTC

Space Weather Message Code: WARK04
Serial Number: 5310
Issue Time: 2026 Apr 03 2102 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5309
Valid From: 2026 Apr 02 0047 UTC
Now Valid Until: 2026 Apr 04 2359 UTC
Warning Condition: Persistence

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

Potential Impacts: Area of impact primarily poleward of 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.

21:01 UTC

Space Weather Message Code: ALTK06
Serial Number: 711
Issue Time: 2026 Apr 03 2101 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2026 Apr 03 2059 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.

21:01 UTC

Space Weather Message Code: WARK05
Serial Number: 2222
Issue Time: 2026 Apr 03 2101 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2221
Valid From: 2026 Apr 02 0230 UTC
Now Valid Until: 2026 Apr 04 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.

19:08 UTC

Space Weather Message Code: ALTK05
Serial Number: 2004
Issue Time: 2026 Apr 03 1908 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 03 1906 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.

16:47 UTC

Space Weather Message Code: ALTK07
Serial Number: 216
Issue Time: 2026 Apr 03 1647 UTC

ALERT: Geomagnetic K-index of 7
Threshold Reached: 2026 Apr 03 1646 UTC
Synoptic Period: 1500-1800 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.

16:25 UTC

Space Weather Message Code: WARK07
Serial Number: 148
Issue Time: 2026 Apr 03 1625 UTC

WARNING: Geomagnetic K-index of 7 or greater expected
Valid From: 2026 Apr 03 1625 UTC
Valid To: 2026 Apr 03 2359 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.

15:55 UTC

Space Weather Message Code: ALTK06
Serial Number: 710
Issue Time: 2026 Apr 03 1555 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2026 Apr 03 1555 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.

15:52 UTC

Space Weather Message Code: WARK06
Serial Number: 652
Issue Time: 2026 Apr 03 1552 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2026 Apr 03 1551 UTC
Valid To: 2026 Apr 03 2359 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.

15:45 UTC

Space Weather Message Code: SUMSUD
Serial Number: 298
Issue Time: 2026 Apr 03 1545 UTC

SUMMARY: Geomagnetic Sudden Impulse
Observed: 2026 Apr 03 1529 UTC
Deviation: 72 nT
Station: HAD

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

15:42 UTC

Space Weather Message Code: ALTK05
Serial Number: 2003
Issue Time: 2026 Apr 03 1542 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2026 Apr 03 1535 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.

15:29 UTC

Space Weather Message Code: WARSUD
Serial Number: 253
Issue Time: 2026 Apr 03 1529 UTC

WARNING: Geomagnetic Sudden Impulse expected
Valid From: 2026 Apr 03 1529 UTC
Valid To: 2026 Apr 03 1550 UTC
IP Shock Passage Observed: 2026 Apr 03 1503 UTC

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

14:51 UTC

Space Weather Message Code: WARK05
Serial Number: 2221
Issue Time: 2026 Apr 03 1451 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2220
Valid From: 2026 Apr 02 0230 UTC
Now Valid Until: 2026 Apr 03 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.