:Product: 20041031RSGA.txt :Issued: 2004 Oct 31 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 305 Issued at 2200Z on 31 Oct 2004 IA. Analysis of Solar Active Regions and Activity from 30/2100Z to 31/2100Z: Solar activity was moderate for the past 24 hours. Region 691 (N14W40) produced two M-class flares: an M1 at 0226 UT and an M2/Sf at 0532 UT. The M2 was accompanied by type II and type IV radio sweeps. Newly received LASCO data for 30 October indicated a nearly full halo CME after yesterday's M5 x-ray event: the CME is first visible in C2 at 30/1654 UTC and has plane-of sky velocity of about 700-800 km/s. The CME is not symmetric and most of the material appears to be moving away from the southwest limb. Region 691 has become somewhat quieter in the last 24 hours. The leader spots show slight decline, but the trailer spots have been growing. Region 693 (S16E20) showed growth during the past 24 hours, with the emergence of spots in the middle portion of the group, but the region only managed to produce one C-class flare. IB. Solar Activity Forecast: Solar activity is expected to be moderate, with a slight chance for major flare activity. Region 691 is the main threat for moderate or higher activity levels, although Region 693 might also contribute. There is also a slight chance for a proton event from Region 691, given its favorable location on the disk. IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z: The geomagnetic field was quiet to unsettled during the past 24 hours. The > 10 MeV proton enhancement that began yesterday reached a maximum of 2.5 PFU at 30/2150 UTC and has been steadily declining since then. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to continue at quiet to unsettled levels until sometime around mid-day tomorrow (01 November) when transient flow from the energetic solar events of 30 October are expected to arrive at Earth. Active conditions with some periods of minor storm levels are expected to follow and persist for 24-36 hours. Conditions are expected to subside to unsettled to active levels on the third day (03 November). III. Event Probabilities 01 Nov-03 Nov Class M 60/60/60 Class X 15/15/15 Proton 20/20/20 PCAF yellow IV. Penticton 10.7 cm Flux Observed 31 Oct 139 Predicted 01 Nov-03 Nov 140/140/135 90 Day Mean 31 Oct 107 V. Geomagnetic A Indices Observed Afr/Ap 30 Oct 010/017 Estimated Afr/Ap 31 Oct 008/010 Predicted Afr/Ap 01 Nov-03 Nov 020/025-020/030-015/020 VI. Geomagnetic Activity Probabilities 01 Nov-03 Nov A. Middle Latitudes Active 30/30/25 Minor storm 25/25/20 Major-severe storm 15/15/10 B. High Latitudes Active 35/35/30 Minor storm 30/30/25 Major-severe storm 20/20/10