:Product: 20010528RSGA.txt :Issued: 2001 May 28 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 148 Issued at 2200Z on 28 May 2001 IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity was low. Only a few small C-class flares occurred. Although no optical flare reports were received, at least one of the C-class flares (C1 at 28/1556 UTC) was observed by HESSI to be associated with departed Region 9461 (N22, L=162). All of the regions currently on the disk are relatively inactive. New regions numbered include 9479 (N26W56), 9480 (S14E52), and 9481 (N17W44). IB. Solar Activity Forecast: Solar activity is expected to be low. IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field ranged from quiet to active levels. Sustained southward Bz contributed to active conditions from 28/0900 to 2100 UTC. This activity appears to be associated with the passage of the structure (CME) following yesterday's shock. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be unsettled to active for the next 24 hours becoming quiet to unsettled by the second day of the forecast period. III. Event Probabilities 29 May-31 May Class M 20/20/20 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 28 May 143 Predicted 29 May-31 May 140/140/135 90 Day Mean 28 May 169 V. Geomagnetic A Indices Observed Afr/Ap 27 May 008/009 Estimated Afr/Ap 28 May 015/020 Predicted Afr/Ap 29 May-31 May 010/015-008/008-008/008 VI. Geomagnetic Activity Probabilities 29 May-31 May A. Middle Latitudes Active 15/15/15 Minor storm 05/05/05 Major-severe storm 01/01/01 B. High Latitudes Active 20/20/20 Minor storm 05/05/05 Major-severe storm 01/01/01