:Product: 20010327RSGA.txt :Issued: 2001 Mar 27 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 086 Issued at 2200Z on 27 Mar 2001 IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity was moderate. Region 9401 (N22E30) produced an impulsive M2/1N event at 27/1630Z. This event had an associated Type II radio sweep with a speed of 500 km/s. Region 9393 (N17E11) grew significantly in area overnight and maintains a complex beta-gamma-delta magnetic configuration; however, the region has only produced C-class X-ray events during the period. Several other C-class events occurred from Regions 9390 (N14W22), and 9402 (N14W11). New Region 9404 (S06E66) was numbered today. 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 26/2100Z to 27/2100Z: The geomagnetic field was mostly quiet to active. Two different shocks were observed on the ACE spacecraft. The first shock occurred at 27/0108Z with an associated sudden impulse of 27 nT on the Boulder magnetometer at 27/0145Z. This activity was believed to be associated with the CME back on 24 March. The second shock occurred at 27/1718Z with an associated sudden impulse of 10 nT observed on the Boulder magnetometer at 27/1745Z. The second shock was believed to be associated with the halo CME on 25 March. The greater than 10 MeV proton flux at geosynchonous orbit was enhanced during the period, but stayed below event threshold with an observed maximum of approximately 6 pfu. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be predominately unsettled to minor storm conditions with isolated major storm conditions possible during the first day of the period. This possible increase in activity is due to the faint full halo CME seen in LASCO/SOHO imagery on 25 March at approximately 1700Z. The geomagnetic field is expected to return to predominately quiet to unsettled conditions the rest of the period with isolated active conditions possible. III. Event Probabilities 28 Mar-30 Mar Class M 75/75/75 Class X 20/20/20 Proton 15/15/15 PCAF green IV. Penticton 10.7 cm Flux Observed 27 Mar 273 Predicted 28 Mar-30 Mar 235/240/240 90 Day Mean 27 Mar 161 V. Geomagnetic A Indices Observed Afr/Ap 26 Mar 002/006 Estimated Afr/Ap 27 Mar 015/015 Predicted Afr/Ap 28 Mar-30 Mar 020/025-015/015-008/010 VI. Geomagnetic Activity Probabilities 28 Mar-30 Mar A. Middle Latitudes Active 40/30/25 Minor storm 30/20/10 Major-severe storm 10/05/01 B. High Latitudes Active 30/40/30 Minor storm 40/25/15 Major-severe storm 20/10/05