:Product: 20011019RSGA.txt :Issued: 2001 Oct 19 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 292 Issued at 2200Z on 19 Oct 2001 IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity was at high levels. Region 9661 (N16W35) was very active producing two X class flares. The first flare was a X1/2b at 19/0105 UTC with an associated Type II radio sweep (914 km/s). The second flare was a X1/2b at 19/1630 UTC with an associated Type II radio sweep (738 km/s). SOHO/LASCO imagery shows full halo CMEs associated with both events. A Type IV radio sweep was also detected with both CME events. Other activity was centered around Region 9658 (S14W61). This region produced an M5/1b flare at 19/0943 UTC and several other minor M-class and C-class flares. New Region 9674 (S08E34) was numbered today. IB. Solar Activity Forecast: Solar activity is expected to be at moderate to high levels. Region 9658 and Region 9661 are very active producing major flares. There has been very little change in their characteristics from yesterday, so the potential for a major flare remains good. IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: Geomagnetic activity was quiet to unsettled. Greater than 10 MeV proton levels was enhanced due to the two CMEs from Region 9661, but remained just below event threshold. IIB. Geophysical Activity Forecast: Geomagnetic activity is expected to be at quiet to unsettled conditions for day one. Quiet to minor storm levels are expected on day two and three with the possibility for isolated major storm conditions. Analysis of the full halo CME (19/0105 UTC from Region 9661) indicated shock arrival late on day two or early on day three (57-72 hour transit time). The shock arrival from the second full halo CME (19/1630 UTC from Region 9661) is expected to arrive late on day three of the period (76-81 hour transit time). Greater than 10 MeV proton levels may exceed event threshold on the first day of the period. Further enhancements may occur if major flare activity continues. III. Event Probabilities 20 Oct-22 Oct Class M 75/75/75 Class X 20/20/20 Proton 75/50/20 PCAF red IV. Penticton 10.7 cm Flux Observed 19 Oct 248 Predicted 20 Oct-22 Oct 250/250/245 90 Day Mean 19 Oct 189 V. Geomagnetic A Indices Observed Afr/Ap 18 Oct 002/004 Estimated Afr/Ap 19 Oct 006/008 Predicted Afr/Ap 20 Oct-22 Oct 010/012-025/025-030/035 VI. Geomagnetic Activity Probabilities 20 Oct-22 Oct A. Middle Latitudes Active 15/55/55 Minor storm 05/30/30 Major-severe storm 01/05/05 B. High Latitudes Active 20/55/55 Minor storm 15/30/35 Major-severe storm 05/10/10