####018002679#### FXXX12 KWNP 191231 DAYDIS :Product: Forecast Discussion :Issued: 2024 May 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 was at low levels. The largest flare of the period was a C4.1 at 18/1938 UTC from Region 3685 (S13E36, Ehi/beta-gamma). Slight growth was observed in the intermediate spots of Region 3685 and the leader spots of Region 3683 (S24W51, Dai/beta). New Region 3687 (N15E08, Bxo/beta) was numbered. Other activity included an approximate 60 degree filament eruption centered near S40E15 that began after 18/2125 UTC. An associated CME was observed off the S limb in SOHO/LASCO C2 imagery at 18/2257 UTC. Modelling is in progress to determine if there is an Earth-directed component. .Forecast... Solar activity is expected to be low with a chance for M-class flares (R1-R2/Minor-Moderate) and a slight chance for an X-class flare (R3/Strong or greater) on 19-21 May. Energetic Particle .24 hr Summary... The greater than 10 MeV proton flux was slightly elevated, but well below S1 (Minor) levels. The 2 MeV electron flux was at normal to moderate levels. .Forecast... There is a slight chance for the greater than 10 MeV protons reaching S1 (Minor) levels on 19-21 May due to the flare potential of Region 3685. The greater than 2 MeV electron flux is expected to remain at normal to moderate levels, with a chanced for high levels, through 21 May. Solar Wind .24 hr Summary... Solar wind parameters were near nominal levels with solar wind speed ranging from 358-449 km/s. Total field ranged from 4-9 nT while the Bz component was between +2/-7 nT. Phi angle was positive. .Forecast... By late on 19 May, the solar wind environment is expected to see the influences of the passing CME from 15 May. Additional enhancements are then expected on 20 May from the CME that left the Sun on 17 May. CME influences are expected to slowly diminish on 21 May. Geospace .24 hr Summary... The geomagnetic field was quiet to unsettled. .Forecast... Unsettled to active levels are expected late on 19 May due to potential activity from the 15 May CME. By 20 May, unsettled to active levels are expected, with G1 (Minor) storming likely, due to glancing CME effects from the 17 May CME. Mid to late day on 21 May, active levels are expected to decrease to mostly unsettled levels as CME effects gradually diminish. ####018002077#### FXXX10 KWNP 191231 DAYTDF :Product: 3-Day Forecast :Issued: 2024 May 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 3 (below NOAA Scale levels). The greatest expected 3 hr Kp for May 19-May 21 2024 is 4.67 (NOAA Scale G1). NOAA Kp index breakdown May 19-May 21 2024 May 19 May 20 May 21 00-03UT 1.33 3.67 4.00 03-06UT 2.67 3.33 3.67 06-09UT 1.67 2.33 3.00 09-12UT 2.33 2.33 2.67 12-15UT 2.67 4.67 (G1) 3.00 15-18UT 3.00 4.67 (G1) 2.67 18-21UT 3.00 4.00 2.67 21-00UT 3.67 4.00 2.67 Rationale: G1 (Minor) geomagnetic storms are likely on 20 May due to the arrival of the 17 May CME. 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 May 19-May 21 2024 May 19 May 20 May 21 S1 or greater 10% 10% 10% Rationale: There is a slight chance for an S1 (Minor) solar radiation storm on 19-21 May. C. NOAA Radio Blackout Activity and Forecast No radio blackouts were observed over the past 24 hours. Radio Blackout Forecast for May 19-May 21 2024 May 19 May 20 May 21 R1-R2 50% 50% 50% R3 or greater 10% 10% 10% Rationale: There is a chance for R1-R2 (Minor-Moderate) radio blackouts on 19-21 May, with a slight chance for R3 (Strong), due primarily to the flare potential of Region 3685.