:Product: 20011026RSGA.txt :Issued: 2001 Oct 26 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 299 Issued at 2200Z on 26 Oct 2001 IA. Analysis of Solar Active Regions and Activity from 25/2100Z to 26/2100Z: Solar activity was at moderate levels. Region 9678 (N11E07) was quite active producing six C-class flares and one M2/Sn flare at 26/1435 UTC. Radio sweeps at numerous discrete frequencies were reported with the M2/Sn flare. This region continued rapid growth in area coverage to 680 millionths, spot count to 48, and remains a magnetically complex beta-gamma-delta configuration. Region 9672 (S18W41) was also active producing four C-class and one minor M-class flares. As Region 9682 (N11E59) rotates onto the disc it has developed into a major region with good potential for activity. New Region 9683 (N28E30) was numbered today. IB. Solar Activity Forecast: Solar Activity is expected to be at low to moderate levels. There is also a chance of an isolated major flare from Regions 9672, 9678, and 9682. Region 9672 still maintains a complex magnetic configuration and it has not diminished in size or complexity. Continued rapid growth and complexity of Region 9678 makes this region a potential source for a major flare. IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z: The geomagnetic field was at quiet levels. A coronal hole / high speed stream has begun to rotate into a geoeffective position. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to major storm levels. The shock arrival from the X1/2b CME on 25/1502 UTC is expected to arrive late on day one or early on day two of the period. Shock arrival is expected to produce unsettled to minor storm level activity for day one and two of the period. Major storm levels are possible particularly at the higher latitudes. Coronal hole / high speed stream may keep activity at unsettled levels on day three. III. Event Probabilities 27 Oct-29 Oct Class M 75/75/75 Class X 35/35/30 Proton 20/20/15 PCAF yellow IV. Penticton 10.7 cm Flux Observed 26 Oct 237 Predicted 27 Oct-29 Oct 230/225/220 90 Day Mean 26 Oct 197 V. Geomagnetic A Indices Observed Afr/Ap 25 Oct 005/007 Estimated Afr/Ap 26 Oct 006/005 Predicted Afr/Ap 27 Oct-29 Oct 020/020-030/030-015/015 VI. Geomagnetic Activity Probabilities 27 Oct-29 Oct A. Middle Latitudes Active 50/50/50 Minor storm 25/30/20 Major-severe storm 15/15/05 B. High Latitudes Active 45/45/30 Minor storm 35/35/20 Major-severe storm 20/20/10