####018003080#### FXXX12 KWNP 191231 DAYDIS :Product: Forecast Discussion :Issued: 2024 Apr 19 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 this period. Region 3647 (S13E07, Dac/beta-delta) produced three M-flares (R1/Minor), the largest of which was an M2.1 flare at 19/0453 UTC. Region 3647 began to show signs of separation of the shared penumbra between its principle spots. Region 3645 (S09E03, Dai/beta) underwent slight decay in its intermediate spot area and consolidation of the leader and trailing spots. Region 3639 (N29E05, Eai/beta-gamma) slowly decayed throughout the period. New Regions 3649 (N16W17, Bxi/beta) and 3650 (S11E28, Cro/beta) were numbered, but were otherwise unremarkable. Other activity included a large prominence eruption on the SE limb beginning at around 19/0400 UTC, however, the associated CME is not Earth-directed. No Earth-directed CMEs were detected in available data. .Forecast... Solar activity is expected to reach moderate levels on 19-21 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 19-21 Apr. There is a slight chance for the greater than 10 MeV proton flux to exceed S1 (Minor) storm levels over 19-21 Apr due to the flare potential of several active regions on the visible disk. Solar Wind .24 hr Summary... Solar wind conditions became enhanced beginning at 19/0413 UTC due to CME activity. Following CME arrival, total field strength reached 16 nT and the Bz component was sustained southward after 19/0410 with a peak of -14 nT observed. Solar wind speeds reached a peak of 439 km/s at 19/1050 UTC. .Forecast... Enhanced solar wind conditions are expected to prevail over 19-21 Apr due to CME activity (on 19 and 21 Apr) and negative polarity CH HSS influences (on 20-21 Apr). Geospace .24 hr Summary... The geomagnetic field reached active levels this period in response to CME activity. .Forecast... Periods of active conditions and G1 (Minor) storms are expected on 19 Apr due to continued CME activity. Quiet and unsettled conditions are expected on 20 Apr due to waning CME effects followed by the onset of negative polarity CH HSS influences. Periods of active conditions are likely again on 21 Apr due to continued negative polarity CH HSS influences and the anticipated arrival of multiple CMEs from 16-18 Apr. ####018002252#### FXXX10 KWNP 191231 DAYTDF :Product: 3-Day Forecast :Issued: 2024 Apr 19 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 Apr 19-Apr 21 2024 is 4.67 (NOAA Scale G1). NOAA Kp index breakdown Apr 19-Apr 21 2024 Apr 19 Apr 20 Apr 21 00-03UT 2.33 2.00 3.00 03-06UT 1.33 1.00 3.67 06-09UT 4.33 2.00 2.67 09-12UT 4.33 1.00 2.67 12-15UT 4.67 (G1) 2.67 2.00 15-18UT 3.67 2.67 2.00 18-21UT 2.67 3.00 3.00 21-00UT 2.67 3.00 2.00 Rationale: An isolated period of G1 (Minor) storm conditions is expected on 19 Apr due to CME activity. 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 19-Apr 21 2024 Apr 19 Apr 20 Apr 21 S1 or greater 20% 20% 20% Rationale: There is a slight chance for S1 (Minor) solar radiation storm conditions over 19-21 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 0453 UTC. Radio Blackout Forecast for Apr 19-Apr 21 2024 Apr 19 Apr 20 Apr 21 R1-R2 75% 75% 75% R3 or greater 20% 20% 20% Rationale: R1-R2 (Minor-Moderate) events are expected, with a slight chance for R3 (Strong) or greater events, over 19-21 Apr due to the flare potential of several active regions on the visible disk.