:Product: 20031027RSGA.txt :Issued: 2003 Oct 27 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 300 Issued at 2200Z on 27 Oct 2003 IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity has been high. Region 484 (N03W54) produced three M-class flares, including an M7.6/2n at 26/2140 UTC, and an M2.7/2f at 27/0833 UTC that produced a CME observed on LASCO imagery. Region 486 (S16E18) produced two major flares, an M5.0/Sf at 27/0927 UTC and an M6.7/Sf at 27/1243 UTC. Regions 484 and 486 are stable in size and magnetic complexity. Five new regions were numbered today: Region 488 (N09E09), Region 489 (S11E05), Region 490 (S10E25), Region 491 (S06E09), Region 492 (S22W20). Region 488 is noteworthy for its rapid growth during the period. IB. Solar Activity Forecast: Solar activity is expected to be high. Regions 484 and 486 are expected to produce M-class and X-class flares. IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet to active levels. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be unsettled to active. Two partial halo CME events associated with X-class flares on 26 October may cause geomagnetic storming on days one and two. III. Event Probabilities 28 Oct-30 Oct Class M 90/90/90 Class X 50/50/50 Proton 25/25/25 PCAF yellow IV. Penticton 10.7 cm Flux Observed 27 Oct 257 Predicted 28 Oct-30 Oct 250/250/250 90 Day Mean 27 Oct 123 V. Geomagnetic A Indices Observed Afr/Ap 26 Oct 005/010 Estimated Afr/Ap 27 Oct 015/016 Predicted Afr/Ap 28 Oct-30 Oct 020/025-020/025-015/020 VI. Geomagnetic Activity Probabilities 28 Oct-30 Oct A. Middle Latitudes Active 35/35/35 Minor storm 25/25/15 Major-severe storm 15/15/10 B. High Latitudes Active 30/30/30 Minor storm 35/35/25 Major-severe storm 25/25/15