Routine Space Environment Product (Daily)
Issued by NWS
Issued by NWS
202 FXXX12 KWNP 181231 DAYDIS :Product: Forecast Discussion :Issued: 2026 Sep 18 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 continued at very low levels with isolated low-level B-class flaring observed from unnumbered plage regions. There are no numbered sunspot regions currently on the visible disk. No Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar activity is expected to remain at very low levels, with a low chance for isolated C-class flares through 20 Sep. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at moderate levels, reaching a peak flux of 585 pfu observed at 17/1715 UTC. The greater than 10 MeV proton flux remained at background levels. .Forecast... The greater than 2 MeV electron flux is expected to reach high levels through 20 Sep. The greater than 10 MeV proton flux is expected to remain at background levels through 20 Sep. Solar Wind .24 hr Summary... Solar wind parameters continued under weakening negative polarity coronal hole high-speed stream (-CH HSS) influences. Total field strength (Bt) held weak and steady around 4 nT throughout the period. The Bz component fluctuated mildly mostly within a narrow -3 to +3 nT range. Solar wind speeds slowly declined from early values near 485 km/s down to around 400 km/s late in the period. The phi angle remained predominantly negative (towards the Sun). .Forecast... Solar wind parameters are expected to see lingering, weak HSS enhancements into 19 Sep before returning to nominal background conditions by 20 Sep. Geospace .24 hr Summary... The geomagnetic field was at quiet to unsettled levels under declining HSS influences. .Forecast... Geomagnetic activity is likely to experience isolated unsettled periods on 18 Sep, returning to mostly quiet conditions on 19 Sep as HSS influences wane, with quiet conditions prevailing on 20 Sep.