####018002796#### FXXX12 KWNP 201231 DAYDIS :Product: Forecast Discussion :Issued: 2024 Apr 20 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 due to an isolated M1.0 flare at 19/1306 UTC from Region 3647 (S13W08, Dac/beta-delta), which continued to show signs of separation of the shared penumbra between its principle spots. Region 3645 (S09W13, Dai/beta) underwent slight decay in its intermediate spot area and consolidation of the leader and trailing spots. Minor growth was observed in Region 3650 (S11E14, Cao/beta) while the remaining regions were stable or in decay. No Earth-directed CMEs were detected in available coronagraph imagery. .Forecast... Solar activity is expected to reach moderate levels on 20-22 Apr. M-class flares (R1-R2/Minor-Moderate) are expected, with a slight chance for X-class flares (R3/Strong), due to the flare potential of several active regions on the visible disk. Energetic Particle .24 hr Summary... The greater than 2 MeV electron flux was at normal to moderate levels and the greater than 10 MeV proton flux was steady at background levels. .Forecast... The greater than 2 MeV electron flux is expected to continue at normal to moderate levels over 20-22 Apr. There is a slight chance for the greater than 10 MeV proton flux to exceed S1 (Minor) storm levels over 20-22 Apr due to the flare potential of several active regions on the visible disk. Solar Wind .24 hr Summary... Solar wind conditions were enhanced this period following the passage of a CME early on 19 Apr. Total field strength reached 18 nT and the Bz component was sustained southward until 19/1830 UTC with a peak of -17 nT observed. Solar wind speeds reached a peak of 549 km/s at 19/2235 UTC. .Forecast... Enhanced solar wind conditions are expected to prevail over 20-22 Apr due to CME activity (on 20 and 21 Apr) and negative polarity CH HSS influences (on 20-22 Apr). Geospace .24 hr Summary... The geomagnetic field reached G3 (Strong) storm levels this period following the passage of a CME early on 19 Apr. .Forecast... Geomagnetic field activity is expected to be quiet and unsettled on 20 Apr with waning CME effects and the onset of negative polarity CH HSS influences. Periods of active conditions are expected on 21 Apr due to continued CH HSS influences and the anticipated arrival of multiple CMEs from 16-18 Apr. Quiet and unsettled conditions are expected on 22 Apr with waning CH HSS influences. ####018002275#### FXXX10 KWNP 201231 DAYTDF :Product: 3-Day Forecast :Issued: 2024 Apr 20 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 7 (NOAA Scale G3). The greatest expected 3 hr Kp for Apr 20-Apr 22 2024 is 3.67 (below NOAA Scale levels). NOAA Kp index breakdown Apr 20-Apr 22 2024 Apr 20 Apr 21 Apr 22 00-03UT 2.67 3.00 2.33 03-06UT 2.00 3.67 2.67 06-09UT 3.33 2.67 2.00 09-12UT 3.33 2.67 2.33 12-15UT 0.67 2.00 2.00 15-18UT 1.67 2.00 1.67 18-21UT 2.00 3.00 1.67 21-00UT 2.67 2.00 2.33 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 20-Apr 22 2024 Apr 20 Apr 21 Apr 22 S1 or greater 20% 20% 20% Rationale: There is a slight chance for S1 (Minor) conditions on 20-22 Apr due to the flare potential of several active regions on the visible disk. 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 19 2024 1306 UTC. Radio Blackout Forecast for Apr 20-Apr 22 2024 Apr 20 Apr 21 Apr 22 R1-R2 75% 75% 75% R3 or greater 20% 20% 20% Rationale: R1-R2 (Minor-Moderate) radio blackouts are expected, with a slight chance for R3 (Strong) or greater events, over 20-22 Apr due to the flare potential of several active regions on the visible disk.