####018002790#### FXXX12 KWNP 261231 DAYDIS :Product: Forecast Discussion :Issued: 2024 Apr 26 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 levels. Region 3638 (S17, L=233) produced two R1 (Minor) events from the SW limb, the largest of which was an M1.3 flare at 25/1712 UTC. Minor development was observed in Region 3658 (S23W52, Dro/beta) and the remaining regions were either stable or in decay. No Earth-directed CMEs were detected in available imagery. .Forecast... Moderate levels of solar activity are expected on 26-27 Apr, with M-class flares (R1-R2/Minor-Moderate) expected, and a slight chance for an X-class flare (R3/Strong). Solar activity is expected to be low to moderate on 28 Apr, with M-class flare activity likely. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux reached high levels this period with a peak flux of 1,400 pfu observed at 25/1530 UTC. The greater than 10 MeV proton flux was steady at background levels. .Forecast... There is a slight chance for the greater than 10 MeV proton flux to reach S1 (Minor) storm levels on 26-27 Apr due to the flare potential and location of multiple active regions. The 10 MeV proton flux is expected to be at background levels on 28 Apr. The greater than 2 MeV electron flux is expected to be at normal to moderate levels over 26-28 Apr. Solar Wind .24 hr Summary... Solar wind conditions became weakly enhanced at around 26/0018 UTC. Total magnetic field strength reached a peak of 10 nT and the Bz component was sustained southward, by as much as -9 nT, after 26/0215 UTC. Solar wind speed increased from a low of around 280 km/s to a peak of around 385 km/s after 26/0018 UTC. The phi angle was predominately negative throughout the period. .Forecast... Enhanced solar wind conditions are likely over 26-28 Apr due to CH HSS influences and possible transient activity associated with multiple CMEs that are expected to pass in close proximity over the next few days. Geospace .24 hr Summary... The geomagnetic field was quiet and unsettled. .Forecast... Geomagnetic field activity is expected to range from quiet to active levels on 26-28 Apr due to the anticipated influence of CH HSSs combined with potential transient influence of multiple near-miss CMEs from the past several days. A chance for G1 (Minor) storm periods exists on 26-27 Apr should these features arrive at Earth and carry periods of significant southward Bz. ####018002224#### FXXX10 KWNP 261231 DAYTDF :Product: 3-Day Forecast :Issued: 2024 Apr 26 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 3 (below NOAA Scale levels). The greatest expected 3 hr Kp for Apr 26-Apr 28 2024 is 3.67 (below NOAA Scale levels). NOAA Kp index breakdown Apr 26-Apr 28 2024 Apr 26 Apr 27 Apr 28 00-03UT 2.00 2.67 2.67 03-06UT 2.33 3.67 3.00 06-09UT 3.33 3.00 3.67 09-12UT 3.00 2.67 2.67 12-15UT 3.67 2.67 2.67 15-18UT 2.67 2.67 2.67 18-21UT 2.67 3.00 2.00 21-00UT 2.00 3.33 2.00 Rationale: No G1 (Minor) or greater geomagnetic storms are expected. No significant transient or recurrent solar wind features are forecast. 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 Apr 26-Apr 28 2024 Apr 26 Apr 27 Apr 28 S1 or greater 15% 15% 5% Rationale: There is a slight chance for S1 (Minor) storms on 26-27 Apr due to the location and flare potential of multiple active regions. C. NOAA Radio Blackout Activity and Forecast Radio blackouts reaching the R1 levels were observed over the past 24 hours. The largest was at Apr 25 2024 1712 UTC. Radio Blackout Forecast for Apr 26-Apr 28 2024 Apr 26 Apr 27 Apr 28 R1-R2 75% 75% 55% R3 or greater 15% 15% 5% Rationale: R1-R2 (Minor-Moderate) radio blackouts are expected, with a slight chance for an R3 (Strong) event, on 26-27 Apr. R1-R2 events are likely on 28 Apr.