####018002396#### FXXX12 KWNP 110041 DAYDIS :Product: Forecast Discussion :Issued: 2026 Mar 11 0040 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. C-class flare activity occurred from Regions 4381 (N09W69, Cso/beta), 4387 (N09E40, Cro/beta), and 4389 (N13E60, Ero/beta). The largest was a C4.6 at 10/1845 UTC from Region 4381. Regions 4384 (N09W44, Hsx/beta) and 4381 continued to slowly decay. Slight growth was observed in Region 4388 (S15W33, Cri/beta). The rest of the spot groups were relatively stable. No Earth-directed CMEs were observed. .Forecast... Solar activity is expected to be at low levels, with a slight chance for M-class (R1-R2/Minor-Moderate) flares through 13 Mar. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux reached high levels with a peak flux of 1,730 pfu observed at 10/1735 UTC. The greater than 10 MeV proton flux was at background levels. .Forecast... The greater than 2 MeV electron flux is expected to reach high levels on 10-12 Mar. The greater than 10 MeV proton flux is expected to continue at background levels through 12 Mar. Solar Wind .24 hr Summary... Solar wind parameters were mildly enhanced, possibly due to transient influence. Total field increased after 10/1030 UTC to near 9 nT while the Bz ranged from +6/-8 nT. Solar wind speed ranged from 389-500 km/s. Phi angle was mostly negative. .Forecast... Slightly enhanced solar wind parameters are likely to continue through early to midday on 10 Mar. Nominal levels are expected to return on 12 Mar before enhancements are again expected 13 Mar due to the onset of a positive polarity coronal hole high speed stream. Geospace .24 hr Summary... The geomagnetic field was quiet to active levels. .Forecast... The geomagnetic field is expected to be at quiet to active levels on 11 Mar as slightly enhanced solar wind conditions persist. Mostly quiet conditions are expected on 12 Mar. Active levels with isolated G1 (Minor) storming are anticipated 13 Mar due to the onset of positive polarity coronal hole high speed stream. ####018002136#### FXXX10 KWNP 110041 DAYTDF :Product: 3-Day Forecast :Issued: 2026 Mar 11 0040 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 11-Mar 13 2026 is 5.00 (NOAA Scale G1). NOAA Kp index breakdown Mar 11-Mar 13 2026 Mar 11 Mar 12 Mar 13 00-03UT 2.67 1.67 1.67 03-06UT 2.33 1.33 1.33 06-09UT 2.00 1.33 1.33 09-12UT 2.00 1.33 2.67 12-15UT 1.00 1.33 3.33 15-18UT 1.33 1.67 5.00 (G1) 18-21UT 1.00 1.33 4.33 21-00UT 1.67 1.67 4.33 Rationale: Isolated periods of G1 (Minor) storming are possible on 13 Mar because of the onset of a positive polarity coronal hole high speed stream (+CH HSS). 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 11-Mar 13 2026 Mar 11 Mar 12 Mar 13 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 Mar 11-Mar 13 2026 Mar 11 Mar 12 Mar 13 R1-R2 20% 20% 20% R3 or greater 1% 1% 1% Rationale: There exists a slight chance for R1-R2 (Minor-Moderate) radio blackouts over 11-13 Mar.