:Product: 20010524RSGA.txt :Issued: 2001 May 24 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 144 Issued at 2200Z on 24 May 2001 IA. Analysis of Solar Active Regions and Activity from 23/2100Z to 24/2100Z: Solar activity was moderate. Region 9468 (N05E25) produced an M1/1n flare at 24/1944Z. Minor centimetric bursts, a Type II radio sweep (620 km/s), and a CME also accompanied this flare. Region 9468 is a moderately complex group covering 150 millionths of white light area and produced frequent brightness fluctuations throughout the period. A pair of long duration C1 events were observed at 24/0706Z and 24/0901Z, and were likely associated with an impressive CME originating just behind the NE limb. A weak Type II sweep was observed at 24/1712Z, associated with a filament eruption and faint CME near the west limb. The largest region on the visible disk - Region 9463 remains stable in a simple beta configuration. IB. Solar Activity Forecast: Solar activity is expected to be low to moderate. An isolated M-class event is possible from Regions 9463 and 9468. IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z: The geomagnmetic field was quiet to unsettled. We have been under the influence of a high speed coronal hole stream for almost 40 hours, but the geomagnetic response so far has been weak. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled with isolated active periods through days one and two. Active to minor storm conditions are possible on day three in response to the CME at 24/1955Z. III. Event Probabilities 25 May-27 May Class M 30/30/30 Class X 05/05/05 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 24 May 170 Predicted 25 May-27 May 165/170/170 90 Day Mean 24 May 168 V. Geomagnetic A Indices Observed Afr/Ap 23 May 008/011 Estimated Afr/Ap 24 May 008/010 Predicted Afr/Ap 25 May-27 May 008/008-008/010-015/020 VI. Geomagnetic Activity Probabilities 25 May-27 May A. Middle Latitudes Active 20/20/35 Minor storm 05/05/15 Major-severe storm 01/01/05 B. High Latitudes Active 25/25/40 Minor storm 10/10/20 Major-severe storm 01/01/10