Solar Activity Alerts

Space Weather Message Code: WATA20 Serial Number: 1123 Issue Time: 2026 Sep 07 1635 UTC WATCH: Geomagnetic Storm Category G1 Predicted Highest Storm Level Predicted by Day: Sep 08: G1 (Minor) Sep 09: G1 (Minor) Sep 10: None (Below G1) THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT Comment: 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: 5413 Issue Time: 2026 Sep 07 1413 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 5412 Valid From: 2026 Sep 07 0854 UTC Now Valid Until: 2026 Sep 08 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.

:Product: Forecast Discussion :Issued: 2026 Sep 07 1230 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center # Solar Activity .24 hr Summary... Solar activity continued at low levels. The largest flare of the period was a long-duration C2.1/Sf from Region 4524 (N12E19, Cao/beta) at 07/0901 UTC. Despite some coronal dimming in GOES SUVI imagery, no obvious CME was detected in available coronagraph imagery. This region showed separation in its leader spots, with overall decay observed. Region 4528 (S11E57, Hsx/alpha) produced a C1.1 flare at 06/1334 UTC, but was otherwise quiet and unremarkable. The remaining numbered regions on the disk were quiet and mostly unchanged. A large, fast moving CME was first observed in GOES CCOR1 imagery departing the East limb at approximately 07/0200 UTC. Analysis of SUVI and SDO imagery determined this to be a far-sided event with no impacts likely at Earth. Several additional CMEs were observed over the past 24-36 hours. Modeling suggests a possible combined arrival for these eruptions on early 08 Sep into 09 Sep. .Forecast... Solar activity is likely to be at low levels due to occasional C-class flare activity, with a slight chance for M-class flares (R1-R2/Minor-Moderate) through 09 Sep. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux reached high levels at 06/1805 UTC. The greater than 10 MeV proton flux was still slightly elevated, but has returned to near background levels. .Forecast... The greater than 2 MeV electron flux is expected to be at normal to moderate levels, with high levels likely on 07-09 Sep. The greater than 10 MeV proton flux is expected to continue decreasing towards background levels over the remainder of 07 Sep. Levels could increase back up to equal or exceed threshold levels on 08-09 Sep if the anticipated CMEs impact Earth as forecast. Solar Wind .24 hr Summary... Solar wind parameters were largely at nominal levels the first half of the period. Total field averaged near 6 nT, the Bz component fluctuated between +/-6 nT, and solar wind speeds averaged around 350 km/s. The exception was the IMF beginning at roughly 06/2040 UTC. Around this time, a coherent magnetic structure began rotating through the near-Earth environment, with Bt reaching a max of 11 nT and Bz turning mostly northward. However, little to no magnetic response was observed. Phi was predominantly oriented in a negative position through most of the period. Subsequently, at around 07/0600 UTC, Phi rotated into a positive orientation, total field dropped to 1 nT, and Bz began to move southward. By 07/0645 UTC, total field had rebounded to 12 nT, Bz deviated to -9 nT, Phi was positive, and there was a slight uptick in temp, density, and winds. Total field eventually reached a peak of 18 nT, Bz decreased to -14 nT, and wind speeds peaked at 434 km/s. This was likely the CIR transitioning into the CH HSS. .Forecast... Solar wind enhancements, due to a solar sector boundary crossing (SSBC) combined with influence from a filament CME that left the Sun on 02 Sep, are anticipated to continue through 07 Sep. Further enhancements are likely on 08 Sep into 09 Sep with the anticipated arrival of the multitude of CMEs from the past couple of days, combined with the onset of the CH HSS. Geospace .24 hr Summary... The geomagnetic field was quiet to unsettled, with an isolated active period. .Forecast... The geomagnetic field is expected to be quiet to unsettled, with periodic active levels on 07 Sep due to aforementioned SSBC/CME effects. Unsettled to active levels are then expected on 08-09 Sep, with isolated G1 (Minor) periods likely and a slight chance of reaching G2 (Moderate) levels if the CMEs mentioned previously impact Earth as forecast. Confidence is low on the timing and magnitude of the CME arrivals.

Space Weather Message Code: ALTK04 Serial Number: 2682 Issue Time: 2026 Sep 07 1108 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2026 Sep 07 1107 UTC Synoptic Period: 0900-1200 Active Warning: YES Comment: 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: WARK04 Serial Number: 5412 Issue Time: 2026 Sep 07 0855 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2026 Sep 07 0854 UTC Valid To: 2026 Sep 07 1800 UTC Warning Conditions: Onset Comment: 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.