:Product: 0818RSGA.txt :Issued: 2024 Aug 18 2200 UTC # Prepared jointly by the U.S. Dept. of Commerce, NOAA, # Space Weather Prediction Center and the U.S. Air Force. # Joint USAF/NOAA Solar Geophysical Activity Report and Forecast SDF Number 231 Issued at 2200Z on 18 Aug 2024 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at high levels for the past 24 hours. The largest solar event of the period was a M2 event observed at 18/0204Z from Region 3784 (N16W60). There are currently 10 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is likely to be moderate with a slight chance for an X-class flare on days one, two, and three (19 Aug, 20 Aug, 21 Aug). IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field has been at quiet to minor storm levels for the past 24 hours. Solar wind speed reached a peak of 541 km/s at 18/0109Z. Total IMF reached 20 nT at 18/0832Z. The maximum southward component of Bz reached -7 nT at 18/0839Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 160 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (19 Aug) and quiet levels on days two and three (20 Aug, 21 Aug). Protons have a slight chance of crossing threshold on days one, two, and three (19 Aug, 20 Aug, 21 Aug). III. Event probabilities 19 Aug-21 Aug Class M 70/70/70 Class X 20/20/20 Proton 10/10/10 PCAF green IV. Penticton 10.7 cm Flux Observed 18 Aug 231 Predicted 19 Aug-21 Aug 225/225/215 90 Day Mean 18 Aug 203 V. Geomagnetic A Indices Observed Afr/Ap 17 Aug 024/047 Estimated Afr/Ap 18 Aug 010/013 Predicted Afr/Ap 19 Aug-21 Aug 011/010-006/005-006/005 VI. Geomagnetic Activity Probabilities 19 Aug-21 Aug A. Middle Latitudes Active 30/10/10 Minor Storm 20/01/01 Major-severe storm 05/01/01 B. High Latitudes Active 10/15/15 Minor Storm 20/20/20 Major-severe storm 50/15/15