:Product: 20010519RSGA.txt :Issued: 2001 May 19 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 139 Issued at 2200Z on 19 May 2001 IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity was low. Only occasional C-class flares occurred during the period. The largest event was an optically uncorrelated C6 flare at 19/1438 UTC. This was accompanied by a Type II radio sweep (470 km/s). Although imagery was non-conclusive, it appears that this event originated in Region 9455 (S17W90+) which was at or near the west limb at the time. A non-earth directed coronal mass ejection from this event was detected by the LASCO/SOHO spacecraft. Two new regions were numbered, 9463 (N07E70) and 9464 (S11E70). IB. Solar Activity Forecast: Solar activity is expected to be low with a slight chance of isolated M-class events. IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic field was quiet to active. The greater than 2 MeV electron flux at geosynchronous orbit reached moderate levels during the period. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled. The greater than 2 MeV electron flux can be expected to reach moderate levels during the forecast period. III. Event Probabilities 20 May-22 May Class M 30/30/30 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 19 May 141 Predicted 20 May-22 May 135/130/130 90 Day Mean 19 May 168 V. Geomagnetic A Indices Observed Afr/Ap 18 May 011/011 Estimated Afr/Ap 19 May 012/012 Predicted Afr/Ap 20 May-22 May 008/012-008/012-008/010 VI. Geomagnetic Activity Probabilities 20 May-22 May A. Middle Latitudes Active 20/20/20 Minor storm 05/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 25/25/25 Minor storm 10/10/10 Major-severe storm 01/01/01