:Product: 20020818RSGA.txt :Issued: 2002 Aug 18 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 230 Issued at 2200Z on 18 Aug 2002 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity was at moderate levels. Region 69 (S08W39) produced three M-class events, the largest an M2.3 at 18/1005 UTC (optically correlated via SOHO/LASCO EIT195 imagery). Region 69 has remained unchanged in area coverage and multiple magnetic delta configurations. Spot count has increased to 74 spots due to the slight dissolution to the large central penumbra region. Region 79 (S22E04) has grown rapidly in area and spot count to 310 millionths and 38 spots. New Region 84 (S16E64) was numbered today. IB. Solar Activity Forecast: Solar activity is expected to be moderate to high. Region 69 has the potential for major flare activity. IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field was at quiet to unsettled levels. The expected interplanetary shock from the M5/CME event on 16 Aug was observed at the L1 position by the NASA/ACE spacecraft at 18/1810 UTC. A corresponding sudden impulse of 27 nT was recorded on the Boulder magnetometer at 18/1848 UTC. Greater than 2 MeV electron flux at geosynchronous orbit exceeded event threshold at 18/1420 UTC, reached a maximum value of 1590 pfu at 18/1655 UTC, and fell below threshold value at 18/1905 UTC. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to active levels with a chance of isolated minor storming. Active levels are expected on day one of the forecast period. Quiet to unsettled conditions are expected for day two and three of the period. III. Event Probabilities 19 Aug-21 Aug Class M 80/80/80 Class X 20/20/20 Proton 15/15/15 PCAF yellow IV. Penticton 10.7 cm Flux Observed 18 Aug 241 Predicted 19 Aug-21 Aug 245/245/230 90 Day Mean 18 Aug 168 V. Geomagnetic A Indices Observed Afr/Ap 17 Aug 008/013 Estimated Afr/Ap 18 Aug 015/020 Predicted Afr/Ap 19 Aug-21 Aug 025/025-012/012-010/010 VI. Geomagnetic Activity Probabilities 19 Aug-21 Aug A. Middle Latitudes Active 50/30/25 Minor storm 30/15/10 Major-severe storm 20/05/01 B. High Latitudes Active 40/30/25 Minor storm 30/15/10 Major-severe storm 20/10/01