:Product: 20030921RSGA.txt :Issued: 2003 Sep 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 264 Issued at 2200Z on 21 Sep 2003 IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity was low. Today's activity consisted of occasional low-level C-class flares. Most of these were from Region 464 (N03E62) which is the largest group on the disk with an area of 430 millionths. The other regions on the disk were quiet and stable. IB. Solar Activity Forecast: Solar activity is expected to be low. There is a slight chance for an isolated M-class flare from Region 464. IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field ranged from quiet to active levels, with a period of minor storm at high latitudes from 1200-1500 UTC. High speed solar wind from a coronal hole continues to drive the activity. However, there was a gradual decline in wind speeds from initial values of 650 km/s to day-end values of about 500 km/s. The greater than 2 MeV electron flux was at high levels during the past 24 hours. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be unsettled to active for the next three days. III. Event Probabilities 22 Sep-24 Sep Class M 20/20/20 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 21 Sep 120 Predicted 22 Sep-24 Sep 125/125/120 90 Day Mean 21 Sep 120 V. Geomagnetic A Indices Observed Afr/Ap 20 Sep 034/025 Estimated Afr/Ap 21 Sep 020/020 Predicted Afr/Ap 22 Sep-24 Sep 015/020-015/020-015/020 VI. Geomagnetic Activity Probabilities 22 Sep-24 Sep A. Middle Latitudes Active 35/35/35 Minor storm 20/20/20 Major-severe storm 05/05/05 B. High Latitudes Active 30/30/30 Minor storm 25/25/25 Major-severe storm 10/10/10