Joint USAF/NOAA Report of Solar and Geophysical Activity 11 Dec 2005

Product: Report of Solar-Geophysical Activity Issued: 2005 Dec 11 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 345 Issued at 2200Z on 11 Dec 2005

IA. Analysis of Solar Active Regions and Activity from 10/2100Z to 11/2100Z: Solar activity was low during the past 24 hours due to one C-class flare, a C1 at 1338Z from Region 835 (N18E55). This group is the largest on the disk at 220 millionths and appears to have a simple beta magnetic class.

IB. Solar Activity Forecast: Solar activity is expected to be very low to low for the next three days (12-14 December).

IIA. Geophysical Activity Summary 10/2100Z to 11/2100Z: The geomagnetic field ranged from quiet to active levels, with a minor storm period at high latitudes from 1500-1800Z. Solar wind speed showed an increase up to 550-660 km/s after 0800Z which was accompanied by enhanced interplanetary magnetic field and temperature. The velocity appeared to be slowly declining after 1500Z. These solar wind signatures are consistent with a small coronal-hole-high-speed stream.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be mostly unsettled for the next 24 hours (12 December) with a chance for isolated active periods. Quiet to unsettled levels are expected for 13 December followed by generally quiet conditions for 14 December.

III. Event Probabilities 12 Dec-14 Dec

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

IV. Penticton 10.7 cm Flux

• Observed 11 Dec 093
• Predicted 12 Dec-14 Dec 095/095/095
• 90 Day Mean 11 Dec 085

V. Geomagnetic A Indices

• Observed Afr/Ap 10 Dec 017/012
• Estimated Afr/Ap 11 Dec 010/014
• Predicted Afr/Ap 12 Dec-14 Dec 008/014-005/010-005/005

VI. Geomagnetic Activity Probabilities 12 Dec-14 Dec

A. Middle Latitudes

• Active 25/20/20
• Minor storm 10/10/10
• Major-severe storm 01/01/01

B. High Latitudes

• Active 35/25/25
• Minor storm 15/10/10
• Major-severe storm 05/01/01