:Product: 0831RSGA.txt :Issued: 2011 Aug 31 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 Report of Solar and Geophysical Activity SDF Number 243 Issued at 2200Z on 31 Aug 2011 IA. Analysis of Solar Active Regions and Activity from 30/2100Z to 31/2100Z: Solar activity was low. Regions 1281 (S20E28) and 1283 (N12E61) each produced a single C-class flare, the largest of which was a C5/1f at 30/2246Z from Region 1281. Regions 1281 and 1282 (N25w13) each showed intermediate and trailer spot growth during the period. No significant changes were noted in Region 1283, though analysis was hampered due to limb proximity. New Region 1285 (N29W48), a small Axx group, was numbered. There were no Earth-directed CMEs observed during the period. IB. Solar Activity Forecast: Solar activity is expected to be low through the period (01 - 03 September) with a slight chance for an M-class flare. IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z: Geomagnetic field activity was at quiet levels. IIB. Geophysical Activity Forecast: Geomagnetic field activity is expected to be at quiet levels during days 1 - 2 (01 - 02 September). Activity is expected to increase to quiet to unsettled levels on day 3 (03 September), with a chance for active levels, due to a recurrent coronal hole high-speed stream. III. Event Probabilities 01 Sep-03 Sep Class M 15/15/15 Class X 01/01/01 Proton 01/01/01 PCAF Green IV. Penticton 10.7 cm Flux Observed 31 Aug 109 Predicted 01 Sep-03 Sep 110/110/105 90 Day Mean 31 Aug 097 V. Geomagnetic A Indices Observed Afr/Ap 30 Aug 002/004 Estimated Afr/Ap 31 Aug 002/005 Predicted Afr/Ap 01 Sep-03 Sep 005/005-005/005-008/008 VI. Geomagnetic Activity Probabilities 01 Sep-03 Sep A. Middle Latitudes Active 10/10/20 Minor storm 01/01/05 Major-severe storm 01/01/01 B. High Latitudes Active 15/15/25 Minor storm 01/01/10 Major-severe storm 01/01/01