:Product: 20031221RSGA.txt :Issued: 2003 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 355 Issued at 2200Z on 21 Dec 2003 IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity was low. Occasional low C-class flares were observed in Regions 525 (N09E05) and 528 (N09E37). Both regions continue in a slow growth phase with some weak mixed polarities noted. New Region 530 (S20E64) was numbered today. IB. Solar Activity Forecast: Solar activity is expected to continue at low levels. There is a small chance for an M-class flare from Regions 525 and 528. IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field was unsettled to active. This disturbance is due to elevated solar wind from an elongated transequatorial coronal hole which rotated into a geoeffective position on 20 December. Solar wind speed now exceeds 600 km/s, but predominantly northward IMF Bz is thwarting a more significant response in the geomagnetic field. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to continue at unsettled to active levels through 22 December. The coronal hole high speed solar wind flow in progress now is expected to subside by 23 December. Quiet to unsettled condition are likely on 23-24 December. III. Event Probabilities 22 Dec-24 Dec Class M 20/20/20 Class X 05/05/05 Proton 01/01/01 PCAF Green IV. Penticton 10.7 cm Flux Observed 21 Dec 133 Predicted 22 Dec-24 Dec 140/140/140 90 Day Mean 21 Dec 135 V. Geomagnetic A Indices Observed Afr/Ap 20 Dec 009/016 Estimated Afr/Ap 21 Dec 015/020 Predicted Afr/Ap 22 Dec-24 Dec 015/018-010/010-005/010 VI. Geomagnetic Activity Probabilities 22 Dec-24 Dec A. Middle Latitudes Active 30/20/10 Minor storm 10/05/01 Major-severe storm 05/01/01 B. High Latitudes Active 40/25/15 Minor storm 15/10/05 Major-severe storm 05/01/01