:Product: 20040424RSGA.txt :Issued: 2004 Apr 24 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 115 Issued at 2200Z on 24 Apr 2004 IA. Analysis of Solar Active Regions and Activity from 23/2100Z to 24/2100Z: Solar activity was moderate. Region 597, which has rotated beyond west limb at latitude S08, produced an M1 flare at 23/2112 UTC. The region produced numerous additional C-class flares through around 1400 UTC, but is now behind the limb. Newly numbered Region 599 (N14E51) emerged on the disk and grew steadily. The region had an area of 120 millionths with mature penumbra on the leader and trailer by the time of forecast issue (24/2200 UTC). The group has been producing frequent upper level B-class and lower level C-class flares. Region 596 (S09W21) continues to be the largest group on the disk but was stable and appears to be decaying. IB. Solar Activity Forecast: Solar activity is expected to be low. Region 599 is expected to be the most productive group, although Region 596 might contribute some activity. There is a slight chance for an isolated M-class event sometime during the next three days. IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z: The geomagnetic field was mostly quiet to unsettled. There was an isolated active period at high latitudes between 0900-1200 UTC. Solar wind speed remains slightly elevated with values running between 420 to 480 km/s. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be mostly unsettled with a chance for isolated active periods at high latitudes for the next 24 hours (25 April). Conditions should decline to mostly unsettled levels at all latitudes for the second and third days. III. Event Probabilities 25 Apr-27 Apr Class M 20/20/20 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 24 Apr 112 Predicted 25 Apr-27 Apr 115/115/120 90 Day Mean 24 Apr 107 V. Geomagnetic A Indices Observed Afr/Ap 23 Apr 016/020 Estimated Afr/Ap 24 Apr 010/013 Predicted Afr/Ap 25 Apr-27 Apr 012/015-012/012-010/010 VI. Geomagnetic Activity Probabilities 25 Apr-27 Apr A. Middle Latitudes Active 25/25/20 Minor storm 20/20/15 Major-severe storm 10/10/05 B. High Latitudes Active 30/30/25 Minor storm 25/25/20 Major-severe storm 15/15/10