####018002381#### FXXX12 KWNP 211231 DAYDIS :Product: Forecast Discussion :Issued: 2025 Oct 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 reached low levels. Region 4261 (S05E60, Dao/beta) was numbered this period as it rotated into better viewing conditions. Region 4262 (S12E28, Hsx/alpha) was numbered this period as well, splitting it from Region 4257 (S09E28, Dso/beta). No Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar activity is expected to remain low, with a chance for isolated M-class flares (R1-R2/Minor-Moderate), over through 23 Oct. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels, and the greater than 10 MeV proton flux remained at background levels throughout the period. .Forecast... The greater than 2 MeV electron flux is expected to remain at normal to moderate levels on 22-23 Oct with a chance for high levels perhaps being possible on 21 Oct. The greater than 10 MeV proton flux is expected to remain at background levels through 23 Oct. Solar Wind .24 hr Summary... Solar wind parameters were mildly enhanced this period due to negative polarity CH HSS influences. Total magnetic field strength reached 10 nT, but the Bz component was mostly near neutral or northward. Solar wind speeds exhibited a decreasing trend from ~600 km/s to under 500 km/s by the periods end. Phi was predominantly positive while undertaking brief excursions into the positive solar sector. .Forecast... Mildly enhanced solar wind conditions and waning negative polarity CH HSS influences are expected to continue through 22 Oct. An ambient-like environment is expected to prevail on 23 Oct. Geospace .24 hr Summary... The geomagnetic field was quiet to unsettled in response to weak negative polarity CH HSS influences. .Forecast... Quiet to unsettled conditions, with the chance for an isolated active period, are expected to continue through 22 Oct as CH HSS influences wane. Mostly quiet conditions are then expected to prevail on 23 Oct. ####018002115#### FXXX10 KWNP 211231 DAYTDF :Product: 3-Day Forecast :Issued: 2025 Oct 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 # # 3-Day Forecast # A. NOAA Geomagnetic Activity Observation and Forecast The greatest observed 3 hr Kp over the past 24 hours was 3 (below NOAA Scale levels). The greatest expected 3 hr Kp for Oct 21-Oct 23 2025 is 3.33 (below NOAA Scale levels). NOAA Kp index breakdown Oct 21-Oct 23 2025 Oct 21 Oct 22 Oct 23 00-03UT 3.33 2.67 1.67 03-06UT 3.00 2.67 1.33 06-09UT 1.67 2.67 1.33 09-12UT 0.67 1.67 1.33 12-15UT 3.00 1.67 1.33 15-18UT 2.33 0.67 1.33 18-21UT 2.00 1.67 1.67 21-00UT 2.00 2.00 1.67 Rationale: No G1 (Minor) or greater geomagnetic storms are expected. No significant transient or recurrent solar wind features are forecast. 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 21-Oct 23 2025 Oct 21 Oct 22 Oct 23 S1 or greater 1% 1% 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 No radio blackouts were observed over the past 24 hours. Radio Blackout Forecast for Oct 21-Oct 23 2025 Oct 21 Oct 22 Oct 23 R1-R2 25% 25% 25% R3 or greater 5% 5% 5% Rationale: There is a chance for R1-R2 (Minor-Moderate) radio blackouts over 21-23 Oct.