:Product: 0819RSGA.txt :Issued: 2013 Aug 19 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 19 Aug 2013 IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C2 event observed at 19/0920Z from Region 1817 (S19W88). There are currently 10 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 (20 Aug, 21 Aug, 22 Aug). IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: 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 550km/s at 18/2231Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 6050 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on day one (20 Aug), unsettled to active levels on day two (21 Aug) and quiet to active levels on day three (22 Aug). Protons greater than 10 Mev have a slight chance of crossing threshold on day one (20 Aug). III. Event probabilities 20 Aug-22 Aug Class M 25/25/25 Class X 05/05/05 Proton 10/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 19 Aug 128 Predicted 20 Aug-22 Aug 125/120/115 90 Day Mean 19 Aug 113 V. Geomagnetic A Indices Observed Afr/Ap 18 Aug 008/007 Estimated Afr/Ap 19 Aug 006/006 Predicted Afr/Ap 20 Aug-22 Aug 011/014-014/018-014/012 VI. Geomagnetic Activity Probabilities 20 Aug-22 Aug A. Middle Latitudes Active 10/25/20 Minor Storm 05/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 20/20/20 Minor Storm 25/35/35 Major-severe storm 20/30/30