Routine Space Environment Product (Daily)
Issued by NWS
Issued by NWS
449 FXXX12 KWNP 210031 DAYDIS :Product: Forecast Discussion :Issued: 2025 Aug 21 0030 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 at low levels with only C-class flares observed. Region 4187 (S18W08, Dao/beta) grew in overall length and gained an additional leader spot. Region 4190 (N18E56, Axx/alpha) emerged, was numbered, but was otherwise unremarkable. Region 4191 (N10E79, Hsx/alpha) rotated into view and was subsequently numbered as well. It should be noted that classification of 4191 is lower confidence due to fore-shortening effect. Although not Earth-directed, two prominence eruptions were of note. Both emerged from on or just beyond the eastern limb, as observed in GOES-16 SUVI 304 imagery at approximately 20/0424 and 20/0804 UTC, respectively. No Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar activity will likely be at very low to low levels, with a slight chance for M-class flares through 22 August due to the anticipated return of old active regions. Probabilities increase slightly on 23 August due to the anticipated return of old active regions nearing the eastern limb. Energetic Particles .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 August due to high speed stream influences followed by the potential of periphery influences from a CME that left the Sun on 17 August interacting with the near-Earth environment. A return to high levels is possible on 22 August, continuing into 23 August. The greater than 10 MeV proton flux is expected to continue at background levels through 23 August given the lack of dynamic regions. Solar Wind .24 hr Summary... Solar wind parameters reflected negative polarity CH HSS influences. Total field settled, decreasing from 7-8 nT to 4-5 nT. The Bz component was primarily +/- 4 nT. Solar wind speeds tended to average near 600 km/s, but overall exhibited a declining trend ending the period near 575 km/s. Phi was predominantly negative while undertaking brief excursions into the positive solar sector. .Forecast... A disturbed solar wind environment is likely to continue through 22 August due to recurrent, negative polarity CH HSS influences. An outside chance for glancing influences from a CME that left the Sun on 17 August will remain for 21 August, but confidence in this outcome is very low. A return to an ambient-like regime is expected on 23 august. Geospace .24 hr Summary... The geomagnetic field was at quiet to unsettled levels with an early, isolated active period. .Forecast... The geomagnetic field is expected to be at quiet to unsettled levels, with isolated active periods, on 21 August under continued CH HSS effects. A chance for G1 (Minor) geomagnetic storming conditions will persist through 21 August as well, with the outside chance for a late arrival glancing blow from the aforementioned 17 August event. Quiet to unsettled conditions are then expected to continue into the early portions on 22 August as CH HSS effects gradually wane. Primarily quiet conditions are expected to prevail on 23 August.