:Product: 0421RSGA.txt :Issued: 2021 Apr 21 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 111 Issued at 2200Z on 21 Apr 2021 IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 21/0129Z from Region 2817 (N18W79). There are currently 3 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be very low with a chance for a C-class flares and a slight chance for an M-class flare on day one (22 Apr) and expected to be very low with a chance for a C-class flares on day two (23 Apr) and expected to be very low with a slight chance for a C-class flare on day three (24 Apr). IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field has been at quiet to unsettled levels for the past 24 hours. Solar wind speed reached a peak of 605 km/s at 20/2101Z. Total IMF reached 5 nT at 21/0109Z. The maximum southward component of Bz reached -3 nT at 21/0548Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 12719 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on day one (22 Apr) and quiet to active levels on days two and three (23 Apr, 24 Apr). III. Event probabilities 22 Apr-24 Apr Class M 10/05/01 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 21 Apr 078 Predicted 22 Apr-24 Apr 080/078/078 90 Day Mean 21 Apr 076 V. Geomagnetic A Indices Observed Afr/Ap 20 Apr 010/012 Estimated Afr/Ap 21 Apr 007/008 Predicted Afr/Ap 22 Apr-24 Apr 005/005-009/010-009/010 VI. Geomagnetic Activity Probabilities 22 Apr-24 Apr A. Middle Latitudes Active 15/40/40 Minor Storm 01/15/15 Major-severe storm 01/01/01 B. High Latitudes Active 15/10/10 Minor Storm 20/25/25 Major-severe storm 20/50/50