:Product: 0418RSGA.txt :Issued: 2013 Apr 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 108 Issued at 2200Z on 18 Apr 2013 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C6 event observed at 18/1823Z from Region 1719 (N09W91). There are currently 5 numbered sunspot regions on the disk. IB. Solar Activity Forecast: Solar activity is likely to be low with a slight chance for an M-class flare on day one (19 Apr) and likely to be low on day two (20 Apr) and expected to be very low with a chance for a C-class flares on day three (21 Apr). IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: 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 359 km/s at 18/1408Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 126 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet levels on days one, two, and three (19 Apr, 20 Apr, 21 Apr). III. Event probabilities 19 Apr-21 Apr Class M 10/05/05 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 18 Apr 105 Predicted 19 Apr-21 Apr 095/090/090 90 Day Mean 18 Apr 111 V. Geomagnetic A Indices Observed Afr/Ap 17 Apr 002/003 Estimated Afr/Ap 18 Apr 002/002 Predicted Afr/Ap 19 Apr-21 Apr 006/005-005/005-004/005 VI. Geomagnetic Activity Probabilities 19 Apr-21 Apr 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 15/15/15 Major-severe storm 10/10/10