:Product: 20010422RSGA.txt :Issued: 2001 Apr 22 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 112 Issued at 2200Z on 22 Apr 2001 IA. Analysis of Solar Active Regions and Activity from 21/2100Z to 22/2100Z: Solar activity was moderate due to an M3/1N flare at 22/2044 UTC in Region 9433 (N17E26). The flare was associated with a tenflare of 270 sfu and a weak type II sweep. This Region remains a large F-type sunspot group with mixed spot polarities. Spot growth has resulted in the formation of at least two small delta configurations in the central and leading sunspots. IB. Solar Activity Forecast: Solar activity is expected to be moderate. Additional M-class flares are likely in Region 9433. The possibility of a major flare is increasing as sunspot growth and magnetic complexity develops. IIA. Geophysical Activity Summary 21/2100Z to 22/2100Z: The geomagnetic field ranged from quiet to minor storm levels. This activity is most likely related to the passage of one of the CMEs observed over the northwest limb earlier this week. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at active to minor storm levels becoming unsettled to active within the next 24 hours. There is a chance of an energetic proton event if a major flare occurs in Region 9433. III. Event Probabilities 23 Apr-25 Apr Class M 75/75/75 Class X 10/10/10 Proton 05/05/05 PCAF green IV. Penticton 10.7 cm Flux Observed 22 Apr 193 Predicted 23 Apr-25 Apr 205/210/210 90 Day Mean 22 Apr 166 V. Geomagnetic A Indices Observed Afr/Ap 21 Apr 007/007 Estimated Afr/Ap 22 Apr 030/030 Predicted Afr/Ap 23 Apr-25 Apr 015/010-010/010-010/010 VI. Geomagnetic Activity Probabilities 23 Apr-25 Apr A. Middle Latitudes Active 15/10/10 Minor storm 10/05/05 Major-severe storm 05/01/01 B. High Latitudes Active 25/15/10 Minor storm 20/10/05 Major-severe storm 10/05/01