:Product: 20011024RSGA.txt :Issued: 2001 Oct 24 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 297 Issued at 2200Z on 24 Oct 2001 IA. Analysis of Solar Active Regions and Activity from 23/2100Z to 24/2100Z: Solar activity was at low levels. The largest flare was a C6/Sf from Region 9678 (N07E34) at 24/1841 UTC. This region has increased in area (140 millionths), spot count (22) and magnetic complexity (beta-gamma). Region 9672 (S19W13) has increased in arial coverage to 490 millionth, increased spot count to 26 and maintains a beta-gamma-delta magnetic configuration. This region has produced minor C-class flares and has the potential for a major flare. Region 9669 (N14W51) also produced minor C-class flares. IB. Solar Activity Forecast: Solar activity is expected to be at low to moderate levels with a chance of an isolated high level condition. Region 9672 continues to have a good chance of producing a major flare. Region 9678 also has the potential for a major flare. IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z: Geomagnetic activity was at quiet levels. The shock arrival from the two CMEs (M6/2N on 22/1502 UTC and X1/2B on 22/1759 UTC)) appears to have lower shock velocity than expected. No shock signature was observed from the NASA ACE/EPAM, MAG, SWEPAM instruments as of the time of this forecast issue. Greater than 10 MeV protons were elevated but continued slow decay. IIB. Geophysical Activity Forecast: Geomagnetic activity is expected to be at quiet to minor storm levels. Further analysis of the expected CME shock combined with the lack of shock signature by ground and space based instruments indicates that the shock arrival is expected on day one or even early on day two of the period. Shock arrival is expected to result in active to minor storm levels. Geomagnetic activity is expected to return to quiet to unsettled conditions by day three. Greater than 10 MeV protons are expected to remain elevated but continue to decay throughout the period barring a major flare event. III. Event Probabilities 25 Oct-27 Oct Class M 80/75/75 Class X 35/25/25 Proton 25/15/15 PCAF yellow IV. Penticton 10.7 cm Flux Observed 24 Oct 239 Predicted 25 Oct-27 Oct 225/220/215 90 Day Mean 24 Oct 194 V. Geomagnetic A Indices Observed Afr/Ap 23 Oct 010/015 Estimated Afr/Ap 24 Oct 008/010 Predicted Afr/Ap 25 Oct-27 Oct 030/040-015/020-010/015 VI. Geomagnetic Activity Probabilities 25 Oct-27 Oct A. Middle Latitudes Active 50/30/20 Minor storm 30/10/05 Major-severe storm 15/05/01 B. High Latitudes Active 50/30/25 Minor storm 35/20/15 Major-severe storm 15/05/05