:Product: 20001228RSGA.txt :Issued: 2000 Dec 28 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 363 Issued at 2200Z on 28 Dec 2000 IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity was low. Several, mostly small C-class flares were observed. Region 9289 (S06E57) has evolved quickly into the largest and most complex region on the visible disk. It now exhibits an "Eko" beta-gamma spot group nearing 800 millionths of white light area, and was responsible for most of the C-class flares. Region 9279 (S12W77) produced a C2/sf flare at 28/1429Z with an associated Type II sweep. Region 9283 (S11W03) also produced isolated C-class flares, the largest being a C5/sf at 27/2218Z. Perhaps the most impressive event of the period was a large, full halo CME on LASCO imagery at 28/1230Z. There was no optical correlation of the source - the event appears to have originated from the backside of the disk. IB. Solar Activity Forecast: Solar activity is expected to be low to moderate. Region 9289 has potential for isolated M-class flares. IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field was mostly quiet with isolated unsettled conditions at high latitudes. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to continue at quiet to unsettled levels. III. Event Probabilities 29 Dec-31 Dec Class M 50/60/60 Class X 10/10/10 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 28 Dec 185 Predicted 29 Dec-31 Dec 185/185/185 90 Day Mean 28 Dec 173 V. Geomagnetic A Indices Observed Afr/Ap 27 Dec 007/007 Estimated Afr/Ap 28 Dec 008/008 Predicted Afr/Ap 29 Dec-31 Dec 005/010-005/010-005/010 VI. Geomagnetic Activity Probabilities 29 Dec-31 Dec A. Middle Latitudes Active 20/15/15 Minor storm 05/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 30/25/25 Minor storm 10/05/05 Major-severe storm 05/01/01