:Product: 20010822RSGA.txt :Issued: 2001 Aug 22 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 234 Issued at 2200Z on 22 Aug 2001 IA. Analysis of Solar Active Regions and Activity from 21/2100Z to 22/2100Z: Solar activity increased to moderate levels. An M1 X-ray flare peaked at 21/2157 UTC associated with moderate discrete radio bursts and a Type II radio sweep (estimated velocity 740 km/sec). LASCO/EIT images indicated that Region 9591 (S17E63) was the source for this flare. It was also the likely source for an M1 X-ray flare that peaked at 22/1216 UTC. This region also produced occasional, impulsive low- to mid-level C-class flares during the period. Region 9591 continued to rotate into view as the day progressed and is now classed as a moderate-sized F-type spot group. Limb proximity prevented a detailed analysis of this region's magnetic structure, but recent activity suggests at least a moderate degree of magnetic complexity. No remarkable changes occurred in the remaining active regions, including newly numbered Region 9592 (S09W59). IB. Solar Activity Forecast: Activity is expected to be moderate with a good chance for isolated M-class flares from Region 9591. There is also a slight chance for a major flare from this region. IIA. Geophysical Activity Summary 21/2100Z to 22/2100Z: Geomagnetic field activity was at quiet to unsettled levels until 22/0300 UTC, then increased to unsettled to active levels for the remainder of the period. This activity was due to a high-speed stream associated with a recurrent, negative-polarity coronal hole. IIB. Geophysical Activity Forecast: Geomagnetic field activity is expected to be at unsettled to active levels through the period. There will be a slight chance for a proton event during the period. The greater than 2 MeV electron flux at geosynchronous orbit may reach high levels during the first half of the period. III. Event Probabilities 23 Aug-25 Aug Class M 50/50/50 Class X 10/10/10 Proton 05/05/10 PCAF green IV. Penticton 10.7 cm Flux Observed 22 Aug 162 Predicted 23 Aug-25 Aug 170/175/180 90 Day Mean 22 Aug 151 V. Geomagnetic A Indices Observed Afr/Ap 21 Aug 012/014 Estimated Afr/Ap 22 Aug 016/018 Predicted Afr/Ap 23 Aug-25 Aug 015/012-012/010-015/012 VI. Geomagnetic Activity Probabilities 23 Aug-25 Aug A. Middle Latitudes Active 30/20/30 Minor storm 15/10/15 Major-severe storm 05/01/05 B. High Latitudes Active 35/25/35 Minor storm 20/15/20 Major-severe storm 10/05/10