:Product: 20031223RSGA.txt :Issued: 2003 Dec 23 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 357 Issued at 2200Z on 23 Dec 2003 IA. Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: Solar activity was low. Occasional C-class flares were observed from Regions 525 (N08W22) and 528 (N09E09). The largest flare of the period was a C6 flare from Region 525 at 23/1024Z. This region showed little change over the past 24 hours and continues to exhibit some minor mixing of polarity. Region 528 is maintaining its steady growth phase and now exceeds 500 millionths of white light areal coverage in a beta-gamma magnetic configuration. No significant changes were observed in the remaining active regions. IB. Solar Activity Forecast: Solar activity is expected to be low. There is a chance for an M-class flare from Regions 525 and 528. IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field was quiet to unsettled. The coronal hole high speed stream that began on 21 December, has now rotated out of a geoeffective position. Solar wind speed declined from a maximum of near 650 km/s on 22 December, to approximately 500 km/s at the end of this period. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled for the next three days. III. Event Probabilities 24 Dec-26 Dec Class M 20/25/25 Class X 05/05/05 Proton 01/01/01 PCAF Green IV. Penticton 10.7 cm Flux Observed 23 Dec 142 Predicted 24 Dec-26 Dec 145/150/150 90 Day Mean 23 Dec 137 V. Geomagnetic A Indices Observed Afr/Ap 22 Dec 018/015 Estimated Afr/Ap 23 Dec 008/010 Predicted Afr/Ap 24 Dec-26 Dec 005/010-005/010-005/010 VI. Geomagnetic Activity Probabilities 24 Dec-26 Dec A. Middle Latitudes Active 15/10/10 Minor storm 01/01/01 Major-severe storm 01/01/01 B. High Latitudes Active 20/15/15 Minor storm 05/01/01 Major-severe storm 01/01/01