Space Weather Alerts

Space Weather Message Code: ALTTP2
Serial Number: 1450
Issue Time: 2025 Dec 04 0303 UTC

ALERT: Type II Radio Emission
Begin Time: 2025 Dec 04 0246 UTC
Estimated Velocity: 345 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.

Space Weather Message Code: ALTK05
Serial Number: 1923
Issue Time: 2025 Dec 04 0253 UTC

ALERT: Geomagnetic K-index of 5
 Threshold Reached: 2025 Dec 04 0247 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.

Space Weather Message Code: ALTXMF
Serial Number: 503
Issue Time: 2025 Dec 04 0250 UTC

ALERT: X-Ray Flux exceeded M5
Threshold Reached: 2025 Dec 04 0248 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.

Space Weather Message Code: WARK05
Serial Number: 2146
Issue Time: 2025 Dec 03 2356 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 2145
Valid From: 2025 Dec 03 1425 UTC
Now Valid Until: 2025 Dec 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 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.

Space Weather Message Code: WARK04
Serial Number: 5172
Issue Time: 2025 Dec 03 2355 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 5171
Valid From: 2025 Dec 03 1022 UTC
Now Valid Until: 2025 Dec 04 1800 UTC
Warning Condition: Persistence

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

Potential Impacts: Area of impact primarily poleward of 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.

Space Weather Message Code: ALTK05
Serial Number: 1922
Issue Time: 2025 Dec 03 2238 UTC

ALERT: Geomagnetic K-index of 5
 Threshold Reached: 2025 Dec 03 2215 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.

Space Weather Message Code: ALTK07
Serial Number: 200
Issue Time: 2025 Dec 03 2048 UTC

ALERT: Geomagnetic K-index of 7
 Threshold Reached: 2025 Dec 03 2031 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.

Space Weather Message Code: WARK07
Serial Number: 139
Issue Time: 2025 Dec 03 2027 UTC

WARNING: Geomagnetic K-index of 7 or greater expected
Valid From: 2025 Dec 03 2025 UTC
Valid To: 2025 Dec 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.

Space Weather Message Code: ALTK06
Serial Number: 677
Issue Time: 2025 Dec 03 1958 UTC

ALERT: Geomagnetic K-index of 6
 Threshold Reached: 2025 Dec 03 1959 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.

Space Weather Message Code: WARK06
Serial Number: 627
Issue Time: 2025 Dec 03 1953 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2025 Dec 03 1952 UTC
Valid To: 2025 Dec 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.

Space Weather Message Code: ALTK05
Serial Number: 1921
Issue Time: 2025 Dec 03 1941 UTC

ALERT: Geomagnetic K-index of 5
 Threshold Reached: 2025 Dec 03 1941 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.

Space Weather Message Code: ALTK05
Serial Number: 1920
Issue Time: 2025 Dec 03 1452 UTC

ALERT: Geomagnetic K-index of 5
 Threshold Reached: 2025 Dec 03 1443 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.