:Product: 0813RSGA.txt :Issued: 2011 Aug 13 2200 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 225 Issued at 2200Z on 13 Aug 2011 IA. Analysis of Solar Active Regions and Activity from 12/2100Z to 13/2100Z: Solar activity has been very low. The largest X-ray event of the past 24 hours was a B1 flare at 13/1431 UTC in Region 1269 (S21W09). All active regions currently on the solar disk are small and simple. IB. Solar Activity Forecast: Solar activity is expected to be very low for the next three days (14-16 August). There is a slight chance of an isolated C-class X-ray flare. IIA. Geophysical Activity Summary 12/2100Z to 13/2100Z: The geomagnetic field was quiet. Solar wind observations from the NASA ACE spacecraft indicate nominal background conditions with a solar wind speed of about 320 km/s, density near 4 p/cc, and the southward component of the IMF (Bz) fluctuating +/- 4 nT around zero. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels throughout the period. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled for the next three days (14-16 August) as a co-rotating interaction region followed by a negative polarity coronal hole high-speed stream become geoeffective. III. Event Probabilities 14 Aug-16 Aug Class M 01/01/01 Class X 01/01/01 Proton 01/01/01 PCAF Green IV. Penticton 10.7 cm Flux Observed 13 Aug 083 Predicted 14 Aug-16 Aug 082/080/080 90 Day Mean 13 Aug 096 V. Geomagnetic A Indices Observed Afr/Ap 12 Aug 003/005 Estimated Afr/Ap 13 Aug 004/005 Predicted Afr/Ap 14 Aug-16 Aug 012/012-010/010-010/010 VI. Geomagnetic Activity Probabilities 14 Aug-16 Aug A. Middle Latitudes Active 40/30/30 Minor storm 10/10/10 Major-severe storm 01/01/01 B. High Latitudes Active 40/35/30 Minor storm 15/15/10 Major-severe storm 05/05/05