:Product: 20010409RSGA.txt :Issued: 2001 Apr 09 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 099 Issued at 2200Z on 09 Apr 2001 IA. Analysis of Solar Active Regions and Activity from 08/2100Z to 09/2100Z: Solar activity increased to high levels. Region 9415 (S22W07) produced an M7/2B flare at 09/1534 UTC associated with a 1600 SFU Tenflare, Type II and IV radio sweeps, and a full-halo CME. Region 9415 remained a large, magnetically complex group with a strong, persistent magnetic delta configuration within the large leader spot. The remaining regions were simply-structured and showed no significant changes. New Region 9425 (S25W26) was numbered. IB. Solar Activity Forecast: Solar activity is expected to be at moderate to high levels. Region 9415 could produce another major flare during the period. IIA. Geophysical Activity Summary 08/2100Z to 09/2100Z: Geomagnetic field activity ranged from quiet to minor storm levels as CME effects gradually subsided. The greater than 10 MeV proton flux began to rise after today's major flare and was gradually increasing as the period ended. A greater than 100 MeV proton flux enhancement also followed the flare, but did not reach event levels. IIB. Geophysical Activity Forecast: Geomagnetic field activity is expected to decrease to quiet to unsettled levels on 10 April. The CME associated with today's flare is expected to reach Earth during the early hours of 11 April. Active to major storm levels will be possible during 11 - 12 April as the CME passes Earth. The greater than 10 MeV proton flux may increase to event levels early on 10 April. III. Event Probabilities 10 Apr-12 Apr Class M 80/80/80 Class X 25/25/25 Proton 70/25/25 PCAF yellow IV. Penticton 10.7 cm Flux Observed 09 Apr 165 Predicted 10 Apr-12 Apr 165/160/160 90 Day Mean 09 Apr 167 V. Geomagnetic A Indices Observed Afr/Ap 08 Apr 033/041 Estimated Afr/Ap 09 Apr 018/025 Predicted Afr/Ap 10 Apr-12 Apr 012/015-030/035-025/025 VI. Geomagnetic Activity Probabilities 10 Apr-12 Apr A. Middle Latitudes Active 25/30/40 Minor storm 10/30/20 Major-severe storm 05/25/05 B. High Latitudes Active 30/20/40 Minor storm 15/35/15 Major-severe storm 05/20/10