Joint USAF/NOAA Report of Solar and Geophysical Activity 24 Sep 2006

Product: Report of Solar-Geophysical Activity
Issued: 2006 Sep 24 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 267 Issued at 2200Z on 24 Sep 2006

IA. Analysis of Solar Active Regions and Activity from 23/2100Z to 24/2100Z: Solar activity was very low. Region 910 (S09W32) remains the only sunspot group on the visible disk and is now magnetic classification alpha. Both the San Vito and Sagamore Hill radio sites reported a Type II radio sweep with very similar times (24/1526Z – 24/1532Z) with an averaged estimated shock speed of 660 km/s. San Vito reported plage fluctuations and surging that coincided with the Type II radio sweep. An increase in x-ray flux was observed during this period and reached the level of an A9.3 flare. No current imagery is available to aid in determining the possibility that a CME may be associated with this radio event.

IB. Solar Activity Forecast: Solar activity is expected to be very low with a slight chance for an isolated C-class flare from Region 910.

IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z: The geomagnetic field was active with multiple periods of minor storming. Solar wind speed is approximately 650 km/s due to a coronal hole high speed stream.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled with occasional active periods during the forecast period.

III. Event Probabilities 25 Sep-27 Sep

• Class M 01/01/01
• Class X 01/01/01
• Proton 01/01/01
• PCAF Green

IV. Penticton 10.7 cm Flux

• Observed 24 Sep 070
• Predicted 25 Sep-27 Sep 070/070/080

V. Geomagnetic A Indices

• Observed Afr/Ap 23 Sep 007/009
• Estimated Afr/Ap 24 Sep 016/020
• Predicted Afr/Ap 25 Sep-27 Sep 008/008-005/008-006/006

VI. Geomagnetic Activity Probabilities 25 Sep-27 Sep A. Middle Latitudes

• Active 15/15/15
• Minor storm 10/10/10
• Major-severe storm 05/05/05

B. High Latitudes

• Active 20/20/20
• Minor storm 15/15/15
• Major-severe storm 05/05/05