:Product: 0923RSGA.txt :Issued: 2010 Sep 23 2201 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 266 Issued at 2200Z on 23 Sep 2010 IA. Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: Solar activity was very low. Region 1108 (S30W22) has decreased in areal coverage and is an Hkx group with an alpha magnetic configuration. 1109 (N22E54) showed little change in either extent or areal coverage over the past 24 hours and is a Dso group with a beta magnetic configuration. IB. Solar Activity Forecast: Solar activity is expected to be at predominantly very low levels with a chance for C-class activity. IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field has been quiet for the past 24 hours. Data from the ACE spacecraft indicated the arrival of a co-rotating interaction region in advance of a coronal hole high speed stream. The total magnetic field increased to 13 nT at 23/1145Z, Bz remained predominately northward and wind velocity steadily increased, ending the period near 460 km/s. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be mostly unsettled for day one (24 September) and decreasing to quiet to unsettled levels for day two (25 September) due to a recurrent coronal hole high speed stream. Quiet levels are expected to predominate on day three (26 September). III. Event Probabilities 24 Sep-26 Sep Class M 05/05/05 Class X 01/01/01 Proton 01/01/01 PCAF Green IV. Penticton 10.7 cm Flux Observed 23 Sep 084 Predicted 24 Sep-26 Sep 085/085/085 90 Day Mean 23 Sep 079 V. Geomagnetic A Indices Observed Afr/Ap 22 Sep 001/002 Estimated Afr/Ap 23 Sep 005/006 Predicted Afr/Ap 24 Sep-26 Sep 010/010-007/007-005/005 VI. Geomagnetic Activity Probabilities 24 Sep-26 Sep A. Middle Latitudes Active 25/15/05 Minor storm 05/01/01 Major-severe storm 01/01/01 B. High Latitudes Active 30/20/05 Minor storm 10/05/01 Major-severe storm 01/01/01