:Product: 0521RSGA.txt :Issued: 2007 May 21 2203 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 141 Issued at 2200Z on 21 May 2007 IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity was very low. Region 956 (N03W32) is decaying but continues to produce occasional B-class flares. IB. Solar Activity Forecast: Solar activity is expected to continue at very low levels. There is slight chance for a C-class flare from Region 956. IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field was quiet with isolated unsettled periods. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels today. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to range from quiet to minor storm levels. A weak CME observed on 19 May may produce isolated unsettled to active periods on 22 May. A high speed coronal hole stream will rotate into a geoeffective position on 24 May and produce occasional active to minor storm periods. III. Event Probabilities 22 May-24 May Class M 05/05/05 Class X 01/01/01 Proton 01/01/01 PCAF green IV. Penticton 10.7 cm Flux Observed 21 May 073 Predicted 22 May-24 May 075/075/075 90 Day Mean 21 May 074 V. Geomagnetic A Indices Observed Afr/Ap 20 May 006/006 Estimated Afr/Ap 21 May 005/012 Predicted Afr/Ap 22 May-24 May 005/008-005/005-010/015 VI. Geomagnetic Activity Probabilities 22 May-24 May A. Middle Latitudes Active 15/15/30 Minor storm 01/01/10 Major-severe storm 01/01/05 B. High Latitudes Active 20/20/40 Minor storm 05/05/20 Major-severe storm 01/01/10