:Product: 20011216RSGA.txt :Issued: 2001 Dec 16 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 350 Issued at 2200Z on 16 Dec 2001 IA. Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: Solar activity increased to moderate levels. Region 9733 (N14W36) remained the most active sunspot group on the disk. It produced two M-class flares: an M1/2N at 16/0124 UTC and an M1/1f at 16/0328 UTC. Minor radio emission accompanied both flares. Region 9733 decreased slightly in area and magnetic complexity and appeared to lose the magnetic delta configuration within its northernmost spots. However, it retained a moderately complex beta-gamma magnetic classification. Region 9739 (S13W43) appeared to be in a gradual growth phase, but remained simply structured. Region 9742 (N08E64) produced isolated subflares during the period. Magnetogram images suggest this region may possess a moderate degree of magnetic complexity, though it is difficult to gauge given its limb proximity. New Region 9743 (S10E73) produced isolated subflares as it rotated into view. It may represent the return of old Region 9714 (S08, L = 195), which produced M-class flares during its last rotation. New Region 9744 (S06E24) was also numbered. IB. Solar Activity Forecast: Solar activity is expected to be moderate to high. Isolated, low-level M-class flares are likely. Region 9733 may produce a major flare during the period. IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z: Geomagnetic field activity was at quiet to unsettled levels. IIB. Geophysical Activity Forecast: Geomagnetic field activity is expected to remain at quiet to unsettled levels. There will be a chance for a proton flare from Region 9733. III. Event Probabilities 17 Dec-19 Dec Class M 75/75/75 Class X 10/10/10 Proton 10/10/10 PCAF yellow IV. Penticton 10.7 cm Flux Observed 16 Dec 209 Predicted 17 Dec-19 Dec 205/200/195 90 Day Mean 16 Dec 219 V. Geomagnetic A Indices Observed Afr/Ap 15 Dec 010/011 Estimated Afr/Ap 16 Dec 010/012 Predicted Afr/Ap 17 Dec-19 Dec 010/010-008/008-008/008 VI. Geomagnetic Activity Probabilities 17 Dec-19 Dec A. Middle Latitudes Active 20/20/20 Minor storm 05/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 25/25/25 Minor storm 10/10/10 Major-severe storm 01/01/01