####018002163#### FXXX10 KWNP 101231 DAYTDF :Product: 3-Day Forecast :Issued: 2025 Oct 10 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 # # 3-Day Forecast # A. NOAA Geomagnetic Activity Observation and Forecast The greatest observed 3 hr Kp over the past 24 hours was 4 (below NOAA Scale levels). The greatest expected 3 hr Kp for Oct 10-Oct 12 2025 is 5.00 (NOAA Scale G1). NOAA Kp index breakdown Oct 10-Oct 12 2025 Oct 10 Oct 11 Oct 12 00-03UT 3.67 2.33 3.00 03-06UT 2.33 2.00 3.00 06-09UT 2.67 2.33 3.67 09-12UT 2.67 2.33 4.67 (G1) 12-15UT 3.67 3.00 3.00 15-18UT 1.67 3.33 3.67 18-21UT 1.33 3.67 5.00 (G1) 21-00UT 1.33 4.00 3.67 Rationale: G1 (Minor) geomagnetic storms are likely on 12 Oct due to the anticipated influence of a negative polarity CH HSS influences. B. NOAA Solar Radiation Activity Observation and Forecast Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was below S-scale storm level thresholds. Solar Radiation Storm Forecast for Oct 10-Oct 12 2025 Oct 10 Oct 11 Oct 12 S1 or greater 5% 5% 1% Rationale: No S1 (Minor) or greater solar radiation storms are expected. No significant active region activity favorable for radiation storm production is forecast. C. NOAA Radio Blackout Activity and Forecast Radio blackouts reaching the R1 levels were observed over the past 24 hours. The largest was at Oct 09 2025 1231 UTC. Radio Blackout Forecast for Oct 10-Oct 12 2025 Oct 10 Oct 11 Oct 12 R1-R2 25% 25% 25% R3 or greater 5% 5% 5% Rationale: There is a chance for R1-R2 (Minor-Moderate) radio blackouts over 10-12 Oct. ####018002533#### FXXX12 KWNP 101231 DAYDIS :Product: Forecast Discussion :Issued: 2025 Oct 10 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 reached moderate levels following an M2.0 flare (R1-Minor) at 09/1231 UTC from a region just around the NW limb. Only low-level C-class activity was observed from the remaining spotted regions on the visible disk. New Regions 4248 (N08E53, Dao/beta) and 4249 (S18E56, Axx/alpha) were numbered as they emerged late in the period, but were otherwise unremarkable. No other potentially Earth-directed CMEs were identified in available coronagraph imagery. .Forecast... A chance for R1-R2 (Minor-Moderate) radio blackouts exists over 10-12 Oct due to flare potential from several active regions returning from the Suns far side. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux continued to reach high levels with a peak flux of 5,051 pfu at 09/1855 UTC. The greater than 10 MeV proton flux remained below the S1 (Minor) threshold over the past 24 hrs. .Forecast... The greater than 2 MeV electron flux is expected to decrease to normal to moderate levels over 10-12 Oct. The 10 MeV proton flux is expected to remain at background levels over the next three days. Solar Wind .24 hr Summary... Solar wind parameters were slight enhanced due to a minor discontinuity observed early on the 9th. This was marked by a total magnetic field strength (Bt) nT to 12 nT and solar wind speeds of ~400 km/s. Southward periods of Bz were observed to -6 Bz for most of the period. .Forecast... Solar wind parameters are likely to continue at mostly nominal levels over 10 Oct. A recurrent, negative polarity CH HSS is likely to become geoeffective from late on 11 Oct through 12 Oct. This is expected to elevate Bt and solar wind speeds through the end of the forecast period (12 Oct). 09 Geospace .24 hr Summary... Geomagnetic field activity was at quiet to isolated active levels. .Forecast... Geomagnetic field activity is expected to be at quiet to unsettled levels over 10 Oct. Active conditions are expected by late on 11 Oct, with G1 (Minor) geomagnetic storm levels likely on 12 Oct, as a negative polarity CH HSS becomes geoeffective.