:Product: 20010821RSGA.txt :Issued: 2001 Aug 21 2200 UTC # Prepared jointly by the U.S. Dept. of Commerce, NOAA, # Space Environment Center and the U.S. Air Force. # Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 233 Issued at 2200Z on 21 Aug 2001 IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity remained low. Region 9585 (N15E11) produced isolated subflares, none of which were associated with significant X-ray emission. New Region 9591 (S18E71) rotated into view. It was the likely source for a bright surge near SE19 at 21/1050 UTC. A filament erupted from the southwest quadrant around mid-period. The eruption was associated with a long-duration C2 X-ray event that peaked at 21/1303 UTC and a coronal mass ejection that did not appear to be Earth directed. IB. Solar Activity Forecast: Solar activity is expected to be at low to moderate levels. There will be a fair chance for an isolated M-class flare during the period. IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: Geomagnetic field activity ranged from quiet to active levels. Activity increased to unsettled to active levels after 21/0900 UTC. The greater than 10 MeV proton flux remained slightly enhanced and gradually decreased toward background in the wake of the proton event of 16 - 18 August. IIB. Geophysical Activity Forecast: Geomagnetic field activity is expected to be at quiet to unsettled levels during most of the period. III. Event Probabilities 22 Aug-24 Aug Class M 30/30/30 Class X 05/05/05 Proton 01/01/05 PCAF green IV. Penticton 10.7 cm Flux Observed 21 Aug 160 Predicted 22 Aug-24 Aug 165/170/175 90 Day Mean 21 Aug 152 V. Geomagnetic A Indices Observed Afr/Ap 20 Aug 006/010 Estimated Afr/Ap 21 Aug 014/016 Predicted Afr/Ap 22 Aug-24 Aug 012/010-010/010-012/012 VI. Geomagnetic Activity Probabilities 22 Aug-24 Aug A. Middle Latitudes Active 25/20/20 Minor storm 10/10/10 Major-severe storm 01/01/01 B. High Latitudes Active 30/25/25 Minor storm 15/15/15 Major-severe storm 01/01/01