Local 8/18/2025, 6:39:01 PM
UTC 2025-08-18T18:39:01.597Z
Space Weather Message Code: WATA20Serial Number: 1056Issue Time: 2025 Aug 18 1839 UTCWATCH: Geomagnetic Storm Category G1 PredictedHighest Storm Level Predicted by Day:Aug 19: G1 (Minor) Aug 20: G1 (Minor) Aug 21: None (Below G1)THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECTComment: Isolated periods of G1 (Minor) geomagnetic storming are likely 19 August due to recurrent, negative polarity CH HSS effects. Isolated periods of G1 (Minor) geomagnetic storming are likely again on 20 August with continued CH HSS effects coupled with the possibility of glancing influences from a CME that left the Sun on 17 August.NOAA 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 8/18/2025, 6:22:08 AM
UTC 2025-08-18T06:22:08.563Z
Space Weather Message Code: ALTEF3Serial Number: 3518Issue Time: 2025 Aug 18 0622 UTCCONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfuContinuation of Serial Number: 3517Begin Time: 2025 Aug 10 1145 UTCYesterday Maximum 2MeV Flux: 8023 pfuPotential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.
Local 8/17/2025, 8:27:04 AM
UTC 2025-08-17T08:27:04.330Z
Space Weather Message Code: ALTEF3Serial Number: 3517Issue Time: 2025 Aug 17 0827 UTCCONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfuContinuation of Serial Number: 3516Begin Time: 2025 Aug 10 1145 UTCYesterday Maximum 2MeV Flux: 9366 pfuPotential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.