:Product: 20011210RSGA.txt :Issued: 2001 Dec 10 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 344 Issued at 2200Z on 10 Dec 2001 IA. Analysis of Solar Active Regions and Activity from 09/2100Z to 10/2100Z: Solar activity was low. Region 9727 (S21W24) produced today's largest event, a C8/Sf at 0938 UTC. The region produced additional C-class subflares during the period. The group has shown an increase in area of about 35%. The growth primarily consisted of emerging positive polarity flux just north of the dominant negative leader spots. The merging of these opposite polarities across an east west inversion line has led to the formation of a strong delta configuration in the region. Region 9733 (N14E44) is the other region of note on the disk: the group has more clearly rotated into view with a beta-gamma magnetic configuration and produced a couple C-class subflares during the day. A seventeen degree filament near N39E24 disappeared sometime between 0116 UTC and 0545 UTC. IB. Solar Activity Forecast: Solar activity is expected to be mostly moderate for the next three days. There is a small chance, however, for a major flare or a proton producing flare from Region 9727, especially if magnetic flux continues to emerge. IIA. Geophysical Activity Summary 09/2100Z to 10/2100Z: The geomagnetic field has been quiet during the past 24 hours. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled during the next three days. III. Event Probabilities 11 Dec-13 Dec Class M 80/80/80 Class X 20/20/20 Proton 20/20/20 PCAF green IV. Penticton 10.7 cm Flux Observed 10 Dec 219 Predicted 11 Dec-13 Dec 215/215/210 90 Day Mean 10 Dec 219 V. Geomagnetic A Indices Observed Afr/Ap 09 Dec 001/003 Estimated Afr/Ap 10 Dec 005/006 Predicted Afr/Ap 11 Dec-13 Dec 010/008-007/008-007/008 VI. Geomagnetic Activity Probabilities 11 Dec-13 Dec A. Middle Latitudes Active 25/20/20 Minor storm 15/10/10 Major-severe storm 05/01/01 B. High Latitudes Active 30/25/25 Minor storm 15/10/10 Major-severe storm 05/01/01