:Product: 20030907RSGA.txt :Issued: 2003 Sep 07 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 250 Issued at 2200Z on 07 Sep 2003 IA. Analysis of Solar Active Regions and Activity from 06/2100Z to 07/2100Z: Solar activity was low. A long-duration C5 flare occurred at 07/1407Z in Region 450 (S17W63). This flare was characterized in H-alpha imagery by several prolonged bright kernels in ribbon form along a thin NW-SE filament. This event appeared to trigger a large 19 degree filament eruption near S38W18. Minor centimetric radio bursts also accompanied this event, and LASCO imagery revealed a large CME in progress. The X-ray flux was still considerably enhanced by the end of the period. Region 450 is a small, simple beta group in decay. The remaining active regions were either stable or in decay. IB. Solar Activity Forecast: Solar activity is expected to be low to very low. The current X-ray flux levels are elevated following today's eruption, but are expected to return to the pre-flare background level early in the period. Very isolated low C-class flares are possible. IIA. Geophysical Activity Summary 06/2100Z to 07/2100Z: The geomagnetic field was quiet to unsettled. Solar wind speed has declined to below 450 km/s. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to continue at quiet to unsettled levels through day one. A recurring high speed coronal hole stream will likely produce active to minor storm periods on days two and three. Activity on day three may be further enhanced by transient material from today's CME off the SW limb. III. Event Probabilities 08 Sep-10 Sep Class M 05/05/05 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 07 Sep 108 Predicted 08 Sep-10 Sep 100/095/095 90 Day Mean 07 Sep 125 V. Geomagnetic A Indices Observed Afr/Ap 06 Sep 007/012 Estimated Afr/Ap 07 Sep 008/010 Predicted Afr/Ap 08 Sep-10 Sep 012/012-015/015-020/025 VI. Geomagnetic Activity Probabilities 08 Sep-10 Sep A. Middle Latitudes Active 25/35/40 Minor storm 10/15/20 Major-severe storm 01/05/10 B. High Latitudes Active 30/40/50 Minor storm 15/20/30 Major-severe storm 05/10/15