FXXX12 KWNP 120031 DAYDIS :Product: Forecast Discussion :Issued: 2025 Dec 12 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 level flares observed throughout the period. Region 4294 (S15W81, Ekc/beta-gamma-delta) was the primary producer with the largest flare being a C9.7 at 11/1546 UTC. The region is moving beyond the west limb now and is becoming too difficult to characterize due to foreshortening. All other regions were stable or in decay. There were no Earth-directed CMEs in coronagraph imagery. .Forecast... Probabilities for flare activity decrease through 14 Dec as major flare producing regions move beyond the west limb. Chances for R1-R2 (Minor-Moderate) flares decrease from 75% to 55%, and chances for R3 (Strong) decrease from 10% to 5% over the three days. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux remained at moderate levels throughout the period. The greater than 10 MeV proton flux remained at background. .Forecast... Electrons are expected to become elevated through 14 Dec as coronal hole (CH) high speed stream (HSS) originating from the negative polarity CH in the northern hemisphere becomes geoeffective. Electrons will likely surpass the 1,000 pfu threshold during the diurnal maxima. As complex regions in the western hemisphere move beyond the limb, chances for protons to become elevated decrease. There is a 10% chance for an S1 (Minor) radiation storming event on 12 Dec, with chances decreasing to 1% by 14 Dec. Solar Wind .24 hr Summary... Solar wind parameters remained elevated due to what is assumed to be multiple transients and undulations between current sheets. The total field decreased from near 22 nT towards 10 nT. The north-south Bz component remained between +/-16 nT. Solar wind speeds remained between 400-450 km/s. The phi angle was predominantly positive until roughly 11/1300 UTC when rotation into the negative sector occurred. .Forecast... Solar wind is expected to remain slightly elevated early on 12 Dec before trending towards nominal levels by midday. Additional enhancements are likely again late on 12 Dec with the arrival of an incoming co-rotating interacting region associated with a negative polarity CH HSS. Wind speeds with the HSS are expected to rise towards 650 km/s 13-14 Dec. Geospace .24 hr Summary... Due to an enhancement early in the period that sustained a perturbed solar wind environment along with a sector boundary crossing late in the period, the geomagnetic field reached G1-G2 (Minor-Moderate) storming levels. .Forecast... The geomagnetic field is expected to be at unsettled to active levels, with G1 (Minor) storming likely, early on 12 Dec as weak enhancements in the solar wind environment persist. Following a brief respite the latter half of 12 Dec, additional enhancements are likely by the end of 12 Dec through early 13 Dec with the arrival of a CIR/HSS. Unsettled to active levels are likely to continue into 14 Dec as CH HSS influence lingers.