####018002106#### FXXX10 KWNP 291231 DAYTDF :Product: 3-Day Forecast :Issued: 2026 Mar 29 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 Mar 29-Mar 31 2026 is 4.67 (NOAA Scale G1). NOAA Kp index breakdown Mar 29-Mar 31 2026 Mar 29 Mar 30 Mar 31 00-03UT 3.67 3.67 3.67 03-06UT 3.67 4.67 (G1) 3.00 06-09UT 3.33 3.00 2.67 09-12UT 2.33 2.33 2.00 12-15UT 1.67 2.33 2.00 15-18UT 1.67 2.33 2.33 18-21UT 0.67 3.00 2.67 21-00UT 1.00 3.67 2.67 Rationale: G1 (Minor) geomagnetic storming is likely on 30 Mar in response to +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 Mar 29-Mar 31 2026 Mar 29 Mar 30 Mar 31 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 No radio blackouts were observed over the past 24 hours. Radio Blackout Forecast for Mar 29-Mar 31 2026 Mar 29 Mar 30 Mar 31 R1-R2 50% 50% 50% R3 or greater 10% 10% 10% Rationale: There is a chance for R1-R2 (Minor-Moderate) radio blackouts, and a slight chance for an R3 (Strong) event, on 29-31 Mar. ####018002287#### FXXX12 KWNP 291231 DAYDIS :Product: Forecast Discussion :Issued: 2026 Mar 29 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 due to weak C-class flare activity from Regions 4401 (N25W20, Eai/beta), 4404 (N14E39, Hsx/alpha) and 4405 (S27E52, Eao/beta-gamma). New Region 4408 (N09E72, Hsx/alpha) was numbered this period. No significant changes were noticed in the spotted regions. No Earth-directed CMEs were observed in available coronagraph imagery. .Forecast... Solar activity is expected to be low with a high chance (50%) for M-class flares (R1-R2/Minor-Moderate radio blackouts) through 31 Mar. Energetic Particle .24 hr Summary... Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1,600 pfu at 28/1900 UTC. The greater than 10 MeV proton flux remained at background levels. .Forecast... The greater than 2 MeV electron flux is expected to continue to reach high levels through 29 Mar before returning to normal to moderate levels on 30-31 Mar. The greater than 10 MeV proton flux is expected to continue at background levels. Solar Wind .24 hr Summary... Solar wind parameters reflected a mostly nominal regime until approximately 28/2020 UTC when a weak enhancement in the IMF began. Total field increased to 7 nT and the Bz component underwent a southward deflection reaching -7 nT. Solar wind speeds were primarily under 400 km/s. Phi was predominantly in a negative solar sector, but became variable post enhancement. .Forecast... Enhancements from recurrent, positive polarity CH HSS influences are anticipated to begin by late 29 Mar and persist through 30 Mar. Geospace .24 hr Summary... The geomagnetic field was at quiet to active levels. .Forecast... Quiet to active levels are expected on 29 Mar. G1 (Minor) geomagnetic storming is likely on 30 Mar due to recurrent positive polarity CH HSS effects. Unsettled to active conditions are then expected to persist into 31 Mar.