####018002115#### FXXX10 KWNP 051231 DAYTDF :Product: 3-Day Forecast :Issued: 2025 Oct 05 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 05-Oct 07 2025 is 4.67 (NOAA Scale G1). NOAA Kp index breakdown Oct 05-Oct 07 2025 Oct 05 Oct 06 Oct 07 00-03UT 2.67 3.33 2.00 03-06UT 3.33 3.67 2.67 06-09UT 2.67 3.33 3.00 09-12UT 2.00 3.00 2.33 12-15UT 3.00 2.33 4.33 15-18UT 3.00 2.00 3.00 18-21UT 3.33 3.00 4.67 (G1) 21-00UT 3.00 3.33 3.00 Rationale: Periods of G1 (Minor) geomagnetic storms are likely on 07 Oct due to CH HSS influences and the anticipated arrival of two slow-moving CMEs that left the Sun on 03 Oct. 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 05-Oct 07 2025 Oct 05 Oct 06 Oct 07 S1 or greater 10% 10% 10% Rationale: There is a slight chance for S1 (Minor) solar radiation storms over 05-07 Oct. C. NOAA Radio Blackout Activity and Forecast No radio blackouts were observed over the past 24 hours. Radio Blackout Forecast for Oct 05-Oct 07 2025 Oct 05 Oct 06 Oct 07 R1-R2 60% 60% 60% R3 or greater 15% 15% 15% Rationale: R1-R2 (Minor-Moderate) radio blackouts are likely, with a slight chance for an R3 (Strong) or greater event, over 05-07 Oct. ####018002772#### FXXX12 KWNP 051231 DAYDIS :Product: Forecast Discussion :Issued: 2025 Oct 05 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 was at low levels. Region 4241 (N14W02, Dao/beta) produced the largest flare of the period, a C3.5/Sf flare at 04/1752 UTC. Regions 4232 (N04W42, Dhc/beta) and 4236 (N10W50, Ekc/beta-gamma) remained the largest and most complex. A Type II radio sweep (est. 284 km/s) was reported beginning at 04/1643 UTC and appears to be associated with eruptive activity around the Suns west limb. No Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar flare activity is likely to remain at moderate levels (R1-R2/Minor-Moderate), with a slight chance for strong (R3-Strong), over 05-07 Oct. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux measured by the GOES-19 satellite reached high levels, with a peak flux of 14,337 pfu due to persistent +CH HSS effects. The greater than 10 MeV proton flux, as measured by the GOES-18 satellite, remained below the S1 (Minor) threshold over the past 24 hrs. .Forecast... The greater than 2 MeV electron flux is expected to remain at high levels as the CH HSS continues over 05-07 Oct. There is a slight chance the greater than 10 MeV proton flux reaches the S1 (minor) threshold due to the presence of multiple magnetically complex active regions on the visible disk. Solar Wind .24 hr Summary... The solar wind near Earth continued to reflect the influence of a positive polarity CH HSS. Phi angle were oriented in a positive solar sector. Wind speeds generally varied between 450-650 km/s during the period. The total Interplanetary Magnetic Field (Bt) remained around 5 nT, with north/south (Bz) component between -/+ 5 nT. .Forecast... Solar wind parameters are expected to continue at elevated, but waning levels over 05-06 Oct due to ongoing CH HSS influence. An additional enhancement is likely on 07 Sep due to the anticipated arrival of two slow-moving CMEs that left the Sun on 03 Oct. Geospace .24 hr Summary... The geomagnetic field reached active levels due to ongoing CH HSS influence. .Forecast... The geomagnetic field is expected to reach active levels, with a chance for G1 (Minor) storming, over 05-06 Oct under continued CH HSS influence. Periods of G1 (Minor) storming are likely on 07 Oct due to the anticipated arrival of two slow-moving CMEs that left the Sun on 03 Oct.