Joint USAF/NOAA Report of Solar and Geophysical Activity 21 Dec 2008

Product: Report of Solar-Geophysical Activity
Issued: 2008 Dec 21 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 356 Issued at 2200Z on 21 Dec 2008

IA. Analysis of Solar Active Regions and Activity from 20/2100Z to 21/2100Z: Solar activity was very low. The visible disk remained spotless. Please note: the observed Penticton 10.7 cm flux of 69 is estimated today.

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

IIA. Geophysical Activity Summary 20/2100Z to 21/2100Z: The geomagnetic field was at quiet levels.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled on 22 – 23 December. A recurrent coronal hole high speed stream is expected to rotate into a geoeffective position on 22 December and affect the field through the 23rd. Mostly quiet conditions are expected by 24 December.

III. Event Probabilities 22 Dec-24 Dec

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

IV. Penticton 10.7 cm Flux

• Observed 21 Dec 069
• Predicted 22 Dec-24 Dec 069/069/069
• 90 Day Mean 21 Dec 069

V. Geomagnetic A Indices

• Observed Afr/Ap 20 Dec 002/002
• Estimated Afr/Ap 21 Dec 002/005
• Predicted Afr/Ap 22 Dec-24 Dec 010/010-008/008-005/005

VI. Geomagnetic Activity Probabilities 22 Dec-24 Dec

A. Middle Latitudes

• Active 20/15/10
• Minor storm 05/01/01
• Major-severe storm 01/01/01

B. High Latitudes

• Active 20/15/10
• Minor storm 05/01/01
• Major-severe storm 01/01/01