:Product: 20011219RSGA.txt :Issued: 2001 Dec 19 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 353 Issued at 2200Z on 19 Dec 2001 IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity was moderate. Region 9739 (S14W82) produced occasional C-class events and the single M-class flare of the period, an M1/Sf at 19/1706Z. This region has been growing steadily since appearing on the disk on 13 Dec and now exceeds 400 millionths of white light area as it rotates around the west limb. Region 9733 (N13W75) continues to produce minor C-class events as it approaches the west limb. Region 9742 (N12E27) maintains moderate magnetic complexity and size, and produced a C4 flare at 19/0232Z). New Regions 9746 (S18E08) and 9747 (N12E71) were numbered today. IB. Solar Activity Forecast: Solar activity is expected to be low to moderate. Regions 9733 and 9739 have potential to produce an M-class flare on the west limb. Region 9742 also has a slim chance of producing an M-class flare. IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic field was quiet to unsettled. The IMF Bz was mostly southward this period creating prolonged disturbed periods. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to continue at quiet to unsettled levels. Unsettled conditions are likely on days two and three as a southern coronal hole moves into a geoeffectively favorable position. III. Event Probabilities 20 Dec-22 Dec Class M 60/50/50 Class X 10/05/05 Proton 10/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 19 Dec 208 Predicted 20 Dec-22 Dec 205/195/185 90 Day Mean 19 Dec 219 V. Geomagnetic A Indices Observed Afr/Ap 18 Dec 007/008 Estimated Afr/Ap 19 Dec 010/010 Predicted Afr/Ap 20 Dec-22 Dec 008/008-010/010-010/010 VI. Geomagnetic Activity Probabilities 20 Dec-22 Dec A. Middle Latitudes Active 20/25/25 Minor storm 05/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 25/30/30 Minor storm 05/10/10 Major-severe storm 01/01/01