:Product: 1223RSGA.txt :Issued: 2007 Dec 23 2203 UTC # Prepared jointly by the U.S. Dept. of Commerce, NOAA, # Space Weather Prediction Center and the U.S. Air Force. # Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 357 Issued at 2200Z on 23 Dec 2007 IA. Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: Solar activity was very low. The visible disk remains spotless. IB. Solar Activity Forecast: Solar activity is expected to be very low. IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field was mostly quiet. Solar wind speed slowly declined through the period, with values around 475 km/s at forecast issue time. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels again today. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled on 24-25 December, with isolated active periods possible at high latitudes. Quiet conditions are expected to return on 26 December. III. Event Probabilities 24 Dec-26 Dec Class M 01/01/01 Class X 01/01/01 Proton 01/01/01 PCAF Green IV. Penticton 10.7 cm Flux Observed 23 Dec 071 Predicted 24 Dec-26 Dec 072/072/072 90 Day Mean 23 Dec 072 V. Geomagnetic A Indices Observed Afr/Ap 22 Dec 007/007 Estimated Afr/Ap 23 Dec 007/008 Predicted Afr/Ap 24 Dec-26 Dec 007/008-007/008-005/005 VI. Geomagnetic Activity Probabilities 24 Dec-26 Dec A. Middle Latitudes Active 15/15/10 Minor storm 01/01/01 Major-severe storm 01/01/01 B. High Latitudes Active 20/15/15 Minor storm 05/05/05 Major-severe storm 01/01/01