:Product: 0915RSGA.txt :Issued: 2011 Sep 15 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 258 Issued at 2200Z on 15 Sep 2011 IA. Analysis of Solar Active Regions and Activity from 14/2100Z to 15/2100Z: Solar activity was low. Nine C-class flares were observed during the period. The largest was a C4/Sf at 15/0029Z from Region 1297 (S18W64). Region 1295 (N22E30) showed growth in its trailing spots. IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for isolated M-class flares during the period (16-18 September). IIA. Geophysical Activity Summary 14/2100Z to 15/2100Z: The geomagnetic field was at predominantly quiet levels. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels throughout the period. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at predominantly quiet levels on day one (16 September). Unsettled to active levels are possible late on day one, due to the expected arrival of the full halo CME observed at 14/0000Z. Activity is expected to be at unsettled to active levels, with isolated minor storm levels at high latitudes on day two (17 September) as the CME continues. Activity is expected to decrease to quiet to active levels on day three (18 September). III. Event Probabilities 16 Sep-18 Sep Class M 35/35/35 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 15 Sep 141 Predicted 16 Sep-18 Sep 140/140/135 90 Day Mean 15 Sep 101 V. Geomagnetic A Indices Observed Afr/Ap 14 Sep 005/004 Estimated Afr/Ap 15 Sep 004/004 Predicted Afr/Ap 16 Sep-18 Sep 010/010-018/020-010/015 VI. Geomagnetic Activity Probabilities 16 Sep-18 Sep A. Middle Latitudes Active 25/25/25 Minor storm 10/15/10 Major-severe storm 01/05/01 B. High Latitudes Active 30/30/30 Minor storm 15/20/15 Major-severe storm 05/05/01