Routine Space Environment Product (Daily)
Issued by NWS
Issued by NWS
473 FXXX12 KWNP 211231 DAYDIS :Product: Forecast Discussion :Issued: 2025 Aug 21 1230 UTC # Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center # Product description and SWPC contact on the Web # http://www.swpc.noaa.gov/wwire.html # # Forecast Discussion # Solar Activity .24 hr Summary... Solar activity was low. The largest flare was a C3.2 at 21/0011 UTC from Region 4191 (N10E71, Hsx/alpha). Slight decay was observed in Region 4187 (S19W12, Dso/beta). The rest of the spotted regions were relatively stable. Other activity included a partial halo CME first observed in SOHO/LASCO C2 imagery at 21/0824 UTC. The event was determined to be backsided. No Earth-directed CMEs were observed. .Forecast... Solar activity will likely be at very low to low levels, with a slight chance for M-class flares through 22 Aug due to the anticipated return of old active regions. Probabilities increase slightly on 23 Aug due to the anticipated return of old active regions nearing the eastern limb. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels. The greater than 10 MeV proton flux was at background levels. .Forecast... The greater than 2 MeV electron flux is expected to be at normal to moderate levels through 21 Aug due to high speed stream influences followed by the potential of periphery influences from a CME that left the Sun on 17 Aug interacting with the near-Earth environment. A return to high levels is possible on 22 Aug, continuing into 23 Aug. The greater than 10 MeV proton flux is expected to continue at background levels through 23 Aug given the lack of dynamic regions. Solar Wind .24 hr Summary... Solar wind parameters were in decline as HSS conditions began to wane. Solar wind speed decreased from approximately 600 km/s to near 470 km/s. Total field ranged from 2-6 nT while the Bz component was between +6/-4 nT. Phi angle was predominantly negative. .Forecast... A disturbed solar wind environment is likely to continue through 22 Aug due to recurrent, negative polarity CH HSS influences. An outside chance for glancing influences from a CME that left the Sun on 17 Aug will remain for 21 Aug, but confidence in this outcome is very low. A return to an ambient-like regime is expected on 23 Aug. Geospace .24 hr Summary... The geomagnetic field was quiet to unsettled. .Forecast... The geomagnetic field is expected to be quiet to unsettled, with possible isolated active periods through 22 Aug as HSS activity diminishes. Mostly quiet conditions are expected on 23 Aug.