:Product: 0428RSGA.txt :Issued: 2013 Apr 28 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 118 Issued at 2200Z on 28 Apr 2013 IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C4 event observed at 28/2017Z from Region 1733 (S17W42) and it was accompanied by Type II (576 km/s) and Type IV radio emissions. There are currently 5 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 (29 Apr, 30 Apr, 01 May). IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field has been at quiet levels for the past 24 hours. Solar wind speed, as measured by the ACE spacecraft, reached a peak speed of 466 km/s at 27/2157Z. Total IMF reached 5 nT at 28/1238Z. The maximum southward component of Bz reached -4 nT at 28/1249Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 2698 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one and three (29 Apr, 01 May) and quiet to unsettled levels on day two (30 Apr). III. Event probabilities 29 Apr-01 May Class M 25/25/25 Class X 05/05/05 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 28 Apr 132 Predicted 29 Apr-01 May 130/130/130 90 Day Mean 28 Apr 112 V. Geomagnetic A Indices Observed Afr/Ap 27 Apr 006/006 Estimated Afr/Ap 28 Apr 002/003 Predicted Afr/Ap 29 Apr-01 May 004/005-003/005-004/005 VI. Geomagnetic Activity Probabilities 29 Apr-01 May A. Middle Latitudes Active 10/10/10 Minor Storm 01/01/01 Major-severe storm 01/01/01 B. High Latitudes Active 15/15/15 Minor Storm 15/20/15 Major-severe storm 10/20/10