####018002105#### FXXX10 KWNP 161231 DAYTDF :Product: 3-Day Forecast :Issued: 2024 Apr 16 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 16-Apr 18 2024 is 4.67 (NOAA Scale G1). NOAA Kp index breakdown Apr 16-Apr 18 2024 Apr 16 Apr 17 Apr 18 00-03UT 4.00 3.00 4.00 03-06UT 3.33 2.67 4.67 (G1) 06-09UT 4.33 2.00 4.33 09-12UT 4.33 3.00 3.00 12-15UT 3.67 2.00 3.33 15-18UT 3.33 2.00 2.67 18-21UT 3.00 4.00 2.33 21-00UT 3.67 4.00 2.00 Rationale: G1 (Minor) geomagnetic storm levels are likely on 18 Apr due to the arrival of CMEs from 14 and 15 Apr. 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 16-Apr 18 2024 Apr 16 Apr 17 Apr 18 S1 or greater 10% 10% 10% Rationale: There is a slight chance for an S1 (Minor) solar radiation storm on 16-18 Apr. 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 15 2024 1932 UTC. Radio Blackout Forecast for Apr 16-Apr 18 2024 Apr 16 Apr 17 Apr 18 R1-R2 60% 60% 60% R3 or greater 10% 10% 10% Rationale: M-class flares are likely (R1-R2/Minor-Moderate), with a slight chance for an X-class flare (R3/Strong) on 16-18 Apr. ####018002998#### FXXX12 KWNP 161231 DAYDIS :Product: Forecast Discussion :Issued: 2024 Apr 16 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 3639 (N28E43, Eai/beta-gamma) produced multiple M-class flares. The largest was an M4.0 (R1-Minor) flare at 15/1932 UTC. Development and growth was observed in Region 3639, Region 3643 (S13E55, Dai/beta), Region 3638 (S17E39, Cao/beta), Region 3637 (S13E34, Bxo/beta), and Region 3634 (N26W49, Dhi/beta). Low-level M-class (R1) activity was also observed from Region 3634. The remaining regions were either stable or in decay. The faint CME observed off the NE limb at 14/1124 UTC in SOHO/LASCO C2 imagery, likely associated with a long duration C5.0 flare from Region 3636 (S18E20, Cso/beta) at 14/1101 UTC, was analyzed. Another faint partial halo CME was observed at 15/0648 UTC, likely associated with a filament eruption N of Region 3636 at 15/0557 UTC. Analysis of these events suggests a combined Earth-directed component late on 17 through 18 Apr. .Forecast... Solar activity is forecast to be moderate, with M-class flares (R1-R2/Minor-Moderate) likely and a slight chance for an X-class flare (R3/Strong) over 16-18 Apr. Energetic Particle .24 hr Summary... The greater than 10 MeV proton flux was at background levels. The greater than 2 MeV electron flux was at normal to moderate levels. .Forecast... There is a slight chance for a greater than 10 MeV proton event (S1/Minor) over 16-18 Apr. The greater than 2 MeV electron flux is expected to continue at normal to moderate levels through 18 Apr. Solar Wind .24 hr Summary... Solar wind parameters became weakly enhanced after 15/1725 UTC and suggested the arrival of a CME that left the Sun on 12 Apr. Total magnetic field strength increased from 5 nT to a peak of 12 nT. The Bz component reached as far southward as -10 nT. Solar wind speeds only increased from ~330 km/s to between 375-415 km/s. Phi angle was mostly negative. .Forecast... Solar wind conditions are expected to continue at enhanced levels on 16 Apr. Late on 17 Apr and into 18 Apr, additional enhancements are expected due to the anticipated arrival CMEs that left the Sun on 14 and 15 Apr. Geospace .24 hr Summary... The geomagnetic field ranged from quiet to active levels under CME influence. .Forecast... The geomagnetic field is expected continue at unsettled to active levels through 16 Apr due to the passage of a CME from 12 Apr. Additional unsettled to active conditions are expected over on 17-18 Apr, with G1 (Minor) storming likely on 18 Apr, due to the anticipated influence of CMEs that left the Sun on 14 and 15 Apr.