:Product: 20041228RSGA.txt :Issued: 2004 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 2004 IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity increased to low levels today. The plage field in Region 713 (S09W78) showed a significant increase in coverage along with the production of multiple C-class flares today, the largest was a C7/1f event that occurred at 28/0010Z. An increase in the sunspot area and an increase in the magnetic complexity were observed this period. Region 715 (N04E74) began to rotate into view and was numbered today. It is already exhibiting a large asymmetrical sunspot. This region was responsible for the C7/Sf event that occurred at 28/1801Z. IB. Solar Activity Forecast: Solar activity is expected to be at low levels. IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field was at predominantly quiet to unsettled levels. An isolated active period was observed between 28/1800 and 2100Z, likely due to a sustained southward Bz which was observed by the ACE spacecraft. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at predominantly quiet to unsettled levels throughout the period. III. Event Probabilities 29 Dec-31 Dec Class M 15/10/10 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 28 Dec 105 Predicted 29 Dec-31 Dec 110/115/115 90 Day Mean 28 Dec 104 V. Geomagnetic A Indices Observed Afr/Ap 27 Dec 006/007 Estimated Afr/Ap 28 Dec 007/010 Predicted Afr/Ap 29 Dec-31 Dec 005/008-006/008-004/008 VI. Geomagnetic Activity Probabilities 29 Dec-31 Dec A. Middle Latitudes Active 15/15/15 Minor storm 01/01/01 Major-severe storm 01/01/01 B. High Latitudes Active 20/20/20 Minor storm 05/05/05 Major-severe storm 01/01/01