:Product: 20010328RSGA.txt :Issued: 2001 Mar 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 087 Issued at 2200Z on 28 Mar 2001 IA. Analysis of Solar Active Regions and Activity from 27/2100Z to 28/2100Z: Solar activity was moderate. Region 9393 (N13E00) once again produced the most activity with four M-class events during the period. The first was an M1/Sf at 28/0158Z, the second was an M1/Sn at 28/0947Z, the third was an M4/Sf at 28/1240Z and the fourth was an M1/1f at 28/1909Z. Regions 9403 (S13E36) and 9397 (S09E19) produced upper C-class level events. Region 9393 continued growing and currently covers an area of over 2200 millionths in white light. The region is also maintaining a very complex beta-gamma-delta magnetic configuration. Four new regions were numbered today, Region 9405 (S13W20), Region 9406 (N25E67), 9407 (N11E64), and 9408 (S08E38). IB. Solar Activity Forecast: Solar activity is expected to be moderate to high. Region 9393 has the best potential to produce a major flare. IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z: The geomagnetic field was quiet to major storm. Minor to major storm conditions were observed from 28/0900Z to 28/1500Z. An earth-directed full halo CME was seen in LASCO/SOHO imagery. The halo occurred at approximately 28/1300Z and was associated with the M4/Sf event in Region 9393. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be predominately quiet to unsettled with possible isolated active conditions on the first day. Conditions are expected to increase during the middle of the period reaching minor to major storm levels due to a CME passage. Conditions are expected to decrease towards the end of the period to unsettled to active levels. There is the possiblilty for a proton event if Region 9393 produces a major flare event. III. Event Probabilities 29 Mar-31 Mar Class M 75/75/75 Class X 20/20/20 Proton 15/15/15 PCAF yellow IV. Penticton 10.7 cm Flux Observed 28 Mar 274 Predicted 29 Mar-31 Mar 270/265/255 90 Day Mean 28 Mar 162 V. Geomagnetic A Indices Observed Afr/Ap 27 Mar 016/018 Estimated Afr/Ap 28 Mar 024/030 Predicted Afr/Ap 29 Mar-31 Mar 014/015-030/030-020/020 VI. Geomagnetic Activity Probabilities 29 Mar-31 Mar A. Middle Latitudes Active 25/30/40 Minor storm 10/40/30 Major-severe storm 01/15/10 B. High Latitudes Active 30/20/30 Minor storm 15/45/40 Major-severe storm 05/25/20