:Product: 0916RSGA.txt :Issued: 2011 Sep 16 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 259 Issued at 2200Z on 16 Sep 2011 IA. Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: Solar activity remained low. Frequent C-class flares were observed during the period. The largest was a C9/Sf at 16/1136Z from Region 1290 (S13W69). Region 1299 (S21E10) was numbered as a Cro-beta group with 8 spots today. IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for isolated M-class flares during the period (17-19 September). IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z: The geomagnetic field was at quiet levels. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels throughout the period. IIB. Geophysical Activity Forecast: Geomagnetic field activity is expected to be at unsettled to active levels, with isolated minor storm levels at high latitudes, on day one (17 September), due to the effects of the full halo CME observed at 14/0000Z. Activity is expected to decrease to quiet to active levels on day two (18 September). Predominantly quiet levels are expected on day three (19 September). III. Event Probabilities 17 Sep-19 Sep Class M 35/35/35 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 16 Sep 143 Predicted 17 Sep-19 Sep 142/140/140 90 Day Mean 16 Sep 102 V. Geomagnetic A Indices Observed Afr/Ap 15 Sep 004/005 Estimated Afr/Ap 16 Sep 007/010 Predicted Afr/Ap 17 Sep-19 Sep 018/020-010/015-005/005 VI. Geomagnetic Activity Probabilities 17 Sep-19 Sep A. Middle Latitudes Active 25/25/15 Minor storm 10/15/10 Major-severe storm 01/01/01 B. High Latitudes Active 30/30/20 Minor storm 20/15/10 Major-severe storm 05/01/01