:Product: 0818RSGA.txt :Issued: 2008 Aug 18 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 231 Issued at 2200Z on 18 Aug 2008 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity was very low. No flares were observed in the past 24 hours and the solar disk continues to be spotless. IB. Solar Activity Forecast: Solar activity is expected to be very low. IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field was initially quiet to unsettled until about 0600Z when conditions became disturbed due to the onset of a high speed stream from a coronal hole. Activity levels were at active to minor storm levels for the remainder of the period. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be mostly unsettled to active on day one (19 August), due to the persistent effects from the high speed stream. Quiet to unsettled levels are expected on day two (20 August), and quiet levels on day three (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 066 Predicted 19 Aug-21 Aug 066/066/066 90 Day Mean 18 Aug 066 V. Geomagnetic A Indices Observed Afr/Ap 17 Aug 005/007 Estimated Afr/Ap 18 Aug 015/015 Predicted Afr/Ap 19 Aug-21 Aug 012/015-007/010-005/005 VI. Geomagnetic Activity Probabilities 19 Aug-21 Aug A. Middle Latitudes Active 35/10/05 Minor storm 10/01/01 Major-severe storm 01/01/01 B. High Latitudes Active 50/15/05 Minor storm 15/05/01 Major-severe storm 01/01/01