:Product: 20041221RSGA.txt :Issued: 2004 Dec 21 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 356 Issued at 2200Z on 21 Dec 2004 IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity has been very low. Region 713 (S08E22) has produced several B-class flares and retains its beta-gamma magnetic configuration. IB. Solar Activity Forecast: Solar activity is expected to be very low to low. There is a chance for an isolated C-class event from Region 713. IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field was quiet to unsettled with an isolated period of active to minor storm conditions observed at 21/1200 UTC. Solar wind data indicated a possible co-rotating interaction region signature during this period. Solar wind speed ranged from around 350 to 490 km/s with the IMF Bz fluctuating to -14 nT. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be predominately quiet to unsettled with isolated periods of active conditions on 22-23 December due to coronal hole effects. Quiet to unsettled conditions are expected for 24 December. III. Event Probabilities 22 Dec-24 Dec Class M 20/20/20 Class X 01/01/01 Proton 01/01/01 PCAF Green IV. Penticton 10.7 cm Flux Observed 21 Dec 101 Predicted 22 Dec-24 Dec 100/105/105 90 Day Mean 21 Dec 104 V. Geomagnetic A Indices Observed Afr/Ap 20 Dec 002/004 Estimated Afr/Ap 21 Dec 008/015 Predicted Afr/Ap 22 Dec-24 Dec 015/020-010/015-010/010 VI. Geomagnetic Activity Probabilities 22 Dec-24 Dec A. Middle Latitudes Active 25/20/20 Minor storm 10/10/10 Major-severe storm 05/01/01 B. High Latitudes Active 30/30/25 Minor storm 20/15/15 Major-severe storm 05/05/01