Joint USAF/NOAA Report of Solar and Geophysical Activity 22 Dec 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 Dec 22 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 357 Issued at 2200Z on 22 Dec 2008

IA. Analysis of Solar Active Regions and Activity from 21/2100Z to 22/2100Z: Solar activity was very low. The visible disk remained spotless. Please note: the observed Penticton 10.7 cm flux for 21 December was 068.

IB. Solar Activity Forecast: Solar activity is expected to remain at very low levels.

IIA. Geophysical Activity Summary 21/2100Z to 22/2100Z: The geomagnetic field was quiet to unsettled. At about 22/1600Z, ACE measured increases in temperature, density and wind velocity, all indicative of a co-rotating interaction region in advance of a recurrent coronal hole high speed stream. During this period, solar wind speed increased to near 400 km/s while the Bz component of the IMF varied north and south about +/- 10 nT.

IIB. Geophysical Activity Forecast: The geomagnetic field is forecasted to be quiet to unsettled with isolated active periods on 23 December. On 24 – 25 December, effects from the coronal hole are expected to wane, and as a result, the geomagnetic field will be mostly quiet.

III. Event Probabilities 23 Dec-25 Dec

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

IV. Penticton 10.7 cm Flux

• Observed 22 Dec 068
• Predicted 23 Dec-25 Dec 068/068/068
• 90 Day Mean 22 Dec 069

V. Geomagnetic A Indices

• Observed Afr/Ap 21 Dec 001/002
• Estimated Afr/Ap 22 Dec 005/005
• Predicted Afr/Ap 23 Dec-25 Dec 010/010-005/005-005/005

VI. Geomagnetic Activity Probabilities 23 Dec-25 Dec

A. Middle Latitudes

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

B. High Latitudes

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