####018002114#### FXXX10 KWNP 271231 DAYTDF :Product: 3-Day Forecast :Issued: 2024 Apr 27 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 5 (NOAA Scale G1). The greatest expected 3 hr Kp for Apr 27-Apr 29 2024 is 3.67 (below NOAA Scale levels). NOAA Kp index breakdown Apr 27-Apr 29 2024 Apr 27 Apr 28 Apr 29 00-03UT 3.00 3.67 2.67 03-06UT 3.00 3.33 2.00 06-09UT 2.00 3.33 2.33 09-12UT 1.33 3.67 2.67 12-15UT 3.67 3.00 2.33 15-18UT 3.00 2.67 2.33 18-21UT 3.67 2.00 2.33 21-00UT 3.67 2.00 2.67 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 27-Apr 29 2024 Apr 27 Apr 28 Apr 29 S1 or greater 5% 5% 5% Rationale: No S1 (Minor) or greater solar radiation storms are expected. No significant active region activity favorable for radiation storm production is forecast. C. NOAA Radio Blackout Activity and Forecast No radio blackouts were observed over the past 24 hours. Radio Blackout Forecast for Apr 27-Apr 29 2024 Apr 27 Apr 28 Apr 29 R1-R2 40% 30% 30% R3 or greater 5% 5% 5% Rationale: There is a chance for isolated R1-R1 (Minor-Moderate) radio blackouts over 27-29 Apr. ####018002923#### FXXX12 KWNP 271231 DAYDIS :Product: Forecast Discussion :Issued: 2024 Apr 27 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 declined to low levels this period with only C-class flare activity observed. Region 3654 (S08W16, Ehi/beta-gamma) remained the largest region on the disk and exhibited moderate development in the intermediate and trailer spots. Region 3657 (S15W25, Bxo/beta) reemerged with a few rudimentary spots and new Region 3660 (N10E71, Axx/alpha) was numbered. The remaining regions were either stable or in decay. No Earth-directed CMEs were detected in available imagery. .Forecast... Solar activity is expected to be at low levels over 27-29 Apr with a chance for M-class flare (R1-R2/Minor-Moderate) activity. 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 be at normal to moderate levels over 27-29 Apr. The greater than 10 MeV proton flux is expected to persist at background levels over 27-29 Apr. Solar Wind .24 hr Summary... The solar wind environment was enhanced due to likely CME activity early in the period, followed by the onset of positive polarity CH HSS influences. Total field strength reached a peak of 17 nT and the Bz component was sustained southward through the first half of the period, with a peak deflection of -11 nT observed. During the latter half of the period, the Bz component rotated northward with only brief southward deflections observed. Solar wind speeds were steady between 300-350 km/s until 27/0230 UTC, when speed values slowly increased to a period high of around 550 km/s. The phi angle transitioned from negative to positive at 26/1502 UTC. .Forecast... Enhanced solar wind conditions are likely over 27-29 Apr due to CH HSS influences and possible transient activity associated with multiple CMEs that are expected to pass in close proximity over the next few days. Geospace .24 hr Summary... The geomagnetic field was at quiet to G1 (Minor) storm levels this period. .Forecast... Geomagnetic field activity is expected to range from quiet to active levels on 27-28 Apr, and quiet to unsettled levels on 29 Apr, due to the anticipated influence of CH HSSs combined with potential transient influence of multiple near-miss CMEs from the past several days. A chance for G1 (Minor) storm periods exists on 27-28 Apr should these features arrive at Earth and carry periods of significant southward Bz.