####018002305#### FXXX12 KWNP 181231 DAYDIS :Product: Forecast Discussion :Issued: 2026 Jan 18 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 (R1-Minor) levels. Region 4341 (S11E24, Dkc/beta-gamma) produced an impulsive M1.1/1N (R1) flare at 17/2351 UTC, the strongest of the period. Only minor changes were observed in the active regions on the visible disk in the past 24 hours. No Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar activity is likely to remain at moderate levels with a few isolated M-class flares (R1/R2, Minor/Moderate) through 20 Jan. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux reached high levels with a peak flux of 2,760 pfu at 17/1745 UTC. The greater than 10 MeV proton flux remained at background levels. .Forecast... The greater than 2 MeV electron flux is expected to reach high levels through 20 Jan under sustained CH HSS influences. The greater than 10 MeV proton flux is expected to remain at background levels. Solar Wind .24 hr Summary... Solar wind parameters reflected positive polarity CH HSS influences. Total magnetic field strength was between 7-9 nT while the Bz component was primarily northward or near neutral with only a few brief southward deflections reaching -5 nT. Solar wind speeds steadily declined from ~750 km/s to ~550 km/s by end of the reporting period. Phi angle was predominantly oriented in a positive solar sector. .Forecast... Enhanced solar wind conditions are expected to persist through 20 Jan as influence from a recurrent, positive polarity coronal hole will continue over the next three days. Geospace .24 hr Summary... Geomagnetic field activity primarily ranged from unsettled to active levels. .Forecast... G1 (Minor) geomagnetic storming is likely on 18 Jan due to positive polarity CH HSS effects. Unsettled to active levels are expected 19-20 Jan as positive polarity CH HSS effects continue, but gradually weaken. ####018002171#### FXXX10 KWNP 181231 DAYTDF :Product: 3-Day Forecast :Issued: 2026 Jan 18 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 Jan 18-Jan 20 2026 is 4.00 (below NOAA Scale levels). NOAA Kp index breakdown Jan 18-Jan 20 2026 Jan 18 Jan 19 Jan 20 00-03UT 3.00 4.00 3.67 03-06UT 3.67 3.67 3.67 06-09UT 2.67 3.33 3.33 09-12UT 2.33 3.00 3.00 12-15UT 4.00 3.00 2.00 15-18UT 3.67 3.33 2.67 18-21UT 3.33 3.33 3.00 21-00UT 2.67 4.00 3.33 Rationale: No G1 (Minor) or greater geomagnetic storms are expected. 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 Jan 18-Jan 20 2026 Jan 18 Jan 19 Jan 20 S1 or greater 5% 5% 5% 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 Jan 17 2026 2351 UTC. Radio Blackout Forecast for Jan 18-Jan 20 2026 Jan 18 Jan 19 Jan 20 R1-R2 55% 55% 55% R3 or greater 5% 5% 5% Rationale: R1-R2 (Minor-Moderate) radio blackouts are likely over 18-20 Jan due to the flare potential of multiple complex regions on the visible disk.