:Product: 0421RSGA.txt :Issued: 2015 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 2015 IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been at high levels for the past 24 hours. The largest solar event of the period was a M4 event observed at 21/1545Z from Region 2322 (N11W87). There are currently 9 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for M-class flares on days one, two, and three (22 Apr, 23 Apr, 24 Apr). IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field has been at unsettled to active levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 628 km/s at 21/0632Z. Total IMF reached 14 nT at 20/2127Z. The maximum southward component of Bz reached -7 nT at 21/0249Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 1433 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels on day one (22 Apr), quiet to active levels on day two (23 Apr) and quiet levels on day three (24 Apr). III. Event probabilities 22 Apr-24 Apr Class M 30/30/30 Class X 05/05/05 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 21 Apr 154 Predicted 22 Apr-24 Apr 155/160/160 90 Day Mean 21 Apr 130 V. Geomagnetic A Indices Observed Afr/Ap 20 Apr 009/011 Estimated Afr/Ap 21 Apr 020/031 Predicted Afr/Ap 22 Apr-24 Apr 019/025-015/015-007/008 VI. Geomagnetic Activity Probabilities 22 Apr-24 Apr A. Middle Latitudes Active 45/30/20 Minor Storm 25/05/05 Major-severe storm 05/01/01 B. High Latitudes Active 05/15/15 Minor Storm 20/30/25 Major-severe storm 65/35/25