####018003006#### FXXX12 KWNP 210031 DAYDIS :Product: Forecast Discussion :Issued: 2024 Apr 21 0030 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 is currently low with C-class flare activity observed from Regions 3636 (S21W44, Cro/beta), 3638 (S18W22, Cai/beta), 3639 (N29W14, Eac/beta-gamma), 3643 (S13W03, Cro/beta) and 3645 (S09W20, Dai/beta), the largest region on the disk .The largest flare was a C7.5 at 20/1706 UTC from Region 3645. The next largest spot group, Region 3647 (S13W15, Dac/beta-delta), was quiet this period, and continued to show signs of separation of the shared penumbra between its principle spots. Regions 3644 (N13E23, Dao/beta), 3645 and 3650 (S11E05, Cai/beta) displayed slight area growth. 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 21-23 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 Particles .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 21-23 Apr. There is a slight chance for the greater than 10 MeV proton flux to exceed S1 (Minor) storm levels over 21-23 Apr due to the flare potential of several active regions on the visible disk. Solar Wind .24 hr Summary... Solar wind conditions were enhanced early this period following the passage of a CME early on 19 Apr. Total field strength reached 7 nT and the Bz component was sustained southward most of the period with a peak of -6 nT observed. Solar wind speeds reached a peak of 5433km/s at 20/0408 UTC. By periods end, wind speeds were in the 400-450 km/s range. Phi angle was mostly variable through the period. .Forecast... Enhanced solar wind conditions are expected to prevail over 21-23 Apr due to CME activity (on 21 Apr) and negative polarity CH HSS influences (on 21-23 Apr). Geospace .24 hr Summary... The geomagnetic field was at quiet to unsettled levels under waning effects from the CME early on 19 Apr. .Forecast... Geomagnetic field activity is expected to be at unsettled to active levels on 21 Apr quiet 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, increasing to unsettled to active levels with negative polarity CH HSS influences. ####018002131#### FXXX10 KWNP 210031 DAYTDF :Product: 3-Day Forecast :Issued: 2024 Apr 21 0030 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 21-Apr 23 2024 is 3.67 (below NOAA Scale levels). NOAA Kp index breakdown Apr 21-Apr 23 2024 Apr 21 Apr 22 Apr 23 00-03UT 3.00 2.33 2.33 03-06UT 3.67 2.67 3.00 06-09UT 2.67 2.00 3.67 09-12UT 2.67 2.33 3.67 12-15UT 2.00 2.00 2.67 15-18UT 2.00 1.67 2.67 18-21UT 3.00 1.67 2.67 21-00UT 2.00 2.33 3.00 Rationale: No G1 (Minor) or greater geomagnetic storms are expected. 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 21-Apr 23 2024 Apr 21 Apr 22 Apr 23 S1 or greater 20% 20% 20% Rationale: There is a slight chance for S1 (Minor) conditions on 21-23 Apr due to the flare potential of several active regions on the visible disk. C. NOAA Radio Blackout Activity and Forecast No radio blackouts were observed over the past 24 hours. Radio Blackout Forecast for Apr 21-Apr 23 2024 Apr 21 Apr 22 Apr 23 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), over 20-22 Apr due to the flare potential of several active regions on the visible disk.