:Product: 20010515RSGA.txt :Issued: 2001 May 15 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 135 Issued at 2200Z on 15 May 2001 IA. Analysis of Solar Active Regions and Activity from 14/2100Z to 15/2100Z: Solar activity increased to moderate levels. Region 9455 (S17W38) produced an M1/1n flare at 15/0300 UTC associated with Type II and IV radio sweeps and a CME, which did not appear to be Earth-directed. Region 9455 showed no significant changes and maintained a minor degree of magnetic complexity. Minor spot development occurred within Region 9454 (N12E05), which also possessed minor magnetic complexity. New Region 9461 (N15E76) rotated into view. It appeared to be the return of old Region 9433, which produced major flares during its previous two rotations. An impressive eruptive prominence and associated CME occurred from beyond the northeast limb (to the east of new Region 9461) late in the period. A long duration C-class X-ray enhancement was associated with the prominence eruption. IB. Solar Activity Forecast: Solar activity is expected to be at low to moderate levels. Regions 9455 and 9454 appear capable of isolated M-class flare activity. IIA. Geophysical Activity Summary 14/2100Z to 15/2100Z: Geomagnetic field activity ranged from quiet to active levels. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels during the second half of the period. IIB. Geophysical Activity Forecast: Geomagnetic field activity is expected to be at quiet to active levels. The greater than 2 MeV electron flux is expected to reach high levels during the first half of the period. III. Event Probabilities 16 May-18 May Class M 40/40/40 Class X 05/05/05 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 15 May 142 Predicted 16 May-18 May 150/160/170 90 Day Mean 15 May 167 V. Geomagnetic A Indices Observed Afr/Ap 14 May 010/012 Estimated Afr/Ap 15 May 014/015 Predicted Afr/Ap 16 May-18 May 012/015-012/020-010/015 VI. Geomagnetic Activity Probabilities 16 May-18 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