####018003794#### FXXX12 KWNP 110031 DAYDIS :Product: Forecast Discussion :Issued: 2025 Dec 11 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 reached moderate level due to multiple low level (R1-Minor) M-class flares, which all originated from Region 4294 (S15W69, Ekc/beta-gamma-delta). Persistent flux emergence in its leading spot has supported its flare activity over the last two days. Other regions with notable growth were Regions 4304 (N25W36, Cai/beta-gamma) and 4305 (S25E20, Dai/beta-gamma). All other regions were either stable or in decay. Region 4294 was responsible for the largest flare of the period, an M4.4/2B at 10/2208, that was also associated with a 520 sfu Tenflare, a Type-II radio burst (estimated velocity of 849 km/s) and an eruption observed at the SUVI 284A channel. Further coronagraph data is necessary to analyze this eruption. There were no Earth directed CMEs in the available coronagraph imagery. .Forecast... R1-R2 (Minor-Moderate) flare activity is expected (75% chance), with a slight chance (15%) for R3 (Strong) activity. Probabilities remain elevated due to the complexity and history of the large complex of three regions in the southwest part of the disk. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux at geosynchronous orbit reached high levels, with a maximum of 2183 pfu at 10/1735 UTC. The greater than 10 MeV proton flux remained at background. .Forecast... Without the geoeffective positioning of any coronal hole high speed stream until 13 Dec, electrons will continue to trend towards moderate levels through 12 Dec. Due the growth of Region 4294 and its favorable positioning in the west, there remains a slight chance (15%) for an S1 (Minor) radiation storming event on 12 Dec with decreasing chances as it moves beyond the limb. Solar Wind .24 hr Summary... Solar wind parameters have been enhanced throughout much of the period. A weak transient moved through starting around 10/0325 UTC. Total interplanetary magnetic field (Bt) rose to 13 nT with the north-south (Bz) component dropping to a minimum of -7 nT. Wind speeds increased slightly from 350 km/s towards 425 km/s for a brief period. The heliospheric current sheet, as determined by the phi angle, moved from negative (towards the Sun) to positive. Bt remained around 7 nT, wind speeds around 380 km/s until approximately 10/1800 UTC. Between 1800-2100 UTC conditions deteriorate. Bt originally at 11 nT at 10/1824 UTC began dropping and reached a minimum of 2 nT at 10/1957 UTC. Rotation began to occur within the heliospheric sheet with a rise in density. A solar wind signature indicative of a reverse shock. Bt increased up to 17 nT at 10/2013 UTC with the Bz component dropping to -16 nT - both have been holding steady at this magnitude since. .Forecast... Solar wind parameters will remain enhanced going into 11 Dec with nominal conditions being regained once current conditions pass. The co-rotating interacting region (CIR) ahead of the negative polarity coronal hole (CH) high speed stream (HSS) expected to arrive 12 Dec. Geospace .24 hr Summary... The geomagnetic field reached G2 (Moderate) geomagnetic storming levels due to the solar wind disturbance that arrived around 10/2000 UTC. .Forecast... G1-G2 (Minor to Moderate) geomagnetic storming levels are expected to continue into 11 Dec with a return to unsettled to active conditions thereafter. ####018002206#### FXXX10 KWNP 110031 DAYTDF :Product: 3-Day Forecast :Issued: 2025 Dec 11 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 # # 3-Day Forecast # A. NOAA Geomagnetic Activity Observation and Forecast The greatest observed 3 hr Kp over the past 24 hours was 6 (NOAA Scale G2). The greatest expected 3 hr Kp for Dec 11-Dec 13 2025 is 5.67 (NOAA Scale G2). NOAA Kp index breakdown Dec 11-Dec 13 2025 Dec 11 Dec 12 Dec 13 00-03UT 5.67 (G2) 3.33 2.67 03-06UT 5.00 (G1) 2.00 2.33 06-09UT 4.00 2.00 2.33 09-12UT 2.33 3.00 1.67 12-15UT 2.33 2.67 2.00 15-18UT 2.33 3.00 2.67 18-21UT 2.33 3.33 3.33 21-00UT 2.67 3.33 3.67 Rationale: G1-G2 (Minor-Moderate) geomagnetic storms are expected due to the influence of ongoing solar wind transients near Earth, likely associated with a CME partial hit. 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 Dec 11-Dec 13 2025 Dec 11 Dec 12 Dec 13 S1 or greater 15% 10% 5% Rationale: There is a slight chance for S1 (Minor) or greater solar radiation storms on 11-12 Dec. C. NOAA Radio Blackout Activity and Forecast Radio blackouts reaching the R1 levels were observed over the past 24 hours. The largest was at Dec 10 2025 2208 UTC. Radio Blackout Forecast for Dec 11-Dec 13 2025 Dec 11 Dec 12 Dec 13 R1-R2 75% 65% 65% R3 or greater 15% 10% 5% Rationale: R1-R2 (Minor-Moderate) radio blackouts are expected on 11 Dec and likely on 12-13 Dec. There is a slight chance of R3 (Strong) or greater storms on 11-12 Dec. ####018000994#### AXXX82 KWNP 110031 DAYOBS :Product: Summary of Space Weather Observations dayobs.txt :Issued: 2025 Dec 11 0030 UTC # Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center # Product description and SWPC contact on the Web # https://www.swpc.noaa.gov/content/subscription-services # # Summary of Space Weather Observations # :Solar_Region_Summary: 2025 Dec 10 # Region Location Sunspot Characteristics # Helio Spot Spot Mag. # Num Lat.,CMD Long. Area Extent class count class 4294 S15W69 284 800 14 EKC 25 BGD 4296 S15W55 271 420 11 EHO 5 BD 4298 S16W89 305 60 3 CSO 2 B 4299 N21W50 266 20 9 CRO 6 B 4303 S27E10 206 10 1 AXX 1 A 4304 N26W36 252 70 8 CAI 15 BG 4305 S25E20 196 70 7 DAI 10 BG