Joint USAF/NOAA Report of Solar and Geophysical Activity 11 Dec 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 Dec 11 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 346 Issued at 2200Z on 11 Dec 2008

IA. Analysis of Solar Active Regions and Activity from 10/2100Z to 11/2100Z: Solar activity was low. Region 1009 (S25W73) produced a C1 flare today at 0925Z as well as a few B-class flares. The region continues to be a small, relatively simple spot group as it approaches the west limb.

IB. Solar Activity Forecast: Solar activity is expected to be very low in general. There is, however, a chance for an isolated C-class flare during the first day (12 December) as Region 1009 rotates around the solar limb.

IIA. Geophysical Activity Summary 10/2100Z to 11/2100Z: The geomagnetic field was quiet during the past 24 hours. The greater than 2 MeV electron flux reached high levels during the past 24 hours.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be initially quiet tomorrow but an increase to unsettled with a chance for active levels is expected late on the first day (12 December) lasting partway through the second day (13 December) as a high speed solar wind stream rotates into geoeffective position. Activity is expected to be generally quiet on the third day (14 December).

III. Event Probabilities 12 Dec-14 Dec

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

IV. Penticton 10.7 cm Flux

• Observed 11 Dec 070
• Predicted 12 Dec-14 Dec 070/070/070
• 90 Day Mean 11 Dec 068

V. Geomagnetic A Indices

• Observed Afr/Ap 10 Dec 002/002
• Estimated Afr/Ap 11 Dec 005/005
• Predicted Afr/Ap 12 Dec-14 Dec 007/008-010/010-005/005

VI. Geomagnetic Activity Probabilities 12 Dec-14 Dec

A. Middle Latitudes

• Active 15/20/05
• Minor storm 05/05/01
• Major-severe storm 01/01/01

B. High Latitudes

• Active 25/30/15
• Minor storm 10/10/01
• Major-severe storm 01/05/01