Joint USAF/NOAA Report of Solar and Geophysical Activity 25 Aug 2006

Product: Report of Solar-Geophysical Activity
Issued: 2006 Aug 25 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 237 Issued at 2200Z on 25 Aug 2006

IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity remains at very low levels. Region 905 (S08E20), the only sunspot group on the visible disk, produced occasional B-class x-ray enhancements, but was otherwise stable this period.

IB. Solar Activity Forecast: Solar activity is expected to continue at very low levels. There is a slight chance for a C-class flare from Region 905.

IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z: The geomagnetic field was quiet. The greater than 2 MeV electron flux at geosynchronous orbit was high again this period.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled on 26 August. A recurrent high speed coronal hole stream is expected to rotate into a geoeffective position on 27 and 28 August, and produce unsettled to active conditions with isolated minor storm periods.

III. Event Probabilities 26 Aug-28 Aug

• Class M 05/05/05
• Class X 01/01/01
• Proton 01/01/01
• PCAF green

IV. Penticton 10.7 cm Flux

• Observed 25 Aug 077
• Predicted 26 Aug-28 Aug 080/080/075
• 90 Day Mean 25 Aug 077

V. Geomagnetic A Indices

• Observed Afr/Ap 24 Aug 004/005
• Estimated Afr/Ap 25 Aug 005/005
• Predicted Afr/Ap 26 Aug-28 Aug 005/008-010/012-010/012

VI. Geomagnetic Activity Probabilities 26 Aug-28 Aug

A. Middle Latitudes

• Active 20/30/30
• Minor storm 05/10/10
• Major-severe storm 01/05/05

B. High Latitudes

• Active 30/40/40
• Minor storm 10/20/20
• Major-severe storm 05/10/10