:Product: 0818RSGA.txt :Issued: 2010 Aug 18 2201 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 230 Issued at 2200Z on 18 Aug 2010 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity was low. Region 1099 (N17W110) produced two C-class flares during the period. The largest of these was a long-duration C4 flare at 18/0548Z, with an associated Type-II radio sweep with an estimated velocity of 545 km/s. SOHO C3 imagery observed a partial-halo CME at 18/0600Z. This CME is not expected to be Earth-directed. No new regions were numbered. IB. Solar Activity Forecast: Solar activity is expected to be very low, with a slight chance for a C-class flare. IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field was predominantly quiet, with an unsettled period observed at 18/0600Z. An enhancement of the greater than 10 MeV proton flux at geosynchronous orbit began at around 18/0800Z and was associated with the long-duration C4 flare at 18/0548Z. The enhancement peaked around mid-period, then gradually decreased. Todays Penticton 10.7 cm Flux value was estimated. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be predominantly quiet for the next three days (19-21 August). III. Event Probabilities 19 Aug-21 Aug Class M 01/01/01 Class X 01/01/01 Proton 01/01/01 PCAF Green IV. Penticton 10.7 cm Flux Observed 18 Aug 081 Predicted 19 Aug-21 Aug 081/080/080 90 Day Mean 18 Aug 077 V. Geomagnetic A Indices Observed Afr/Ap 17 Aug 003/005 Estimated Afr/Ap 18 Aug 004/005 Predicted Afr/Ap 19 Aug-21 Aug 005/005-005/005-005/005 VI. Geomagnetic Activity Probabilities 19 Aug-21 Aug A. Middle Latitudes Active 10/10/10 Minor storm 01/01/01 Major-severe storm 01/01/01 B. High Latitudes Active 10/10/10 Minor storm 01/01/01 Major-severe storm 01/01/01