Joint USAF/NOAA Report of Solar and Geophysical Activity 17 Dec 2006

Product: Report of Solar-Geophysical Activity
Issued: 2006 Dec 17 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 351 Issued at 2200Z on 17 Dec 2006

IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity has been low. There was a single C-class, long duration flare at approximately 17/1711Z apparently from Region 930 (S06W88). A slow moving CME from the SW limb occurred with very similar timing and may be associated with this flare. Given the position and slow speed of this CME, it is not expected to be geoeffective.

IB. Solar Activity Forecast: Solar activity is expected to be at low to moderate levels.

IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: The geomagnetic field has been quiet to unsettled. The greater than 2 MeV electron flux reached high levels again today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled on December 18 and 19. On December 20 the geomagnetic field is expected to be unsettled to active due to a coronal hole high speed stream rotating into a geoeffective position.

III. Event Probabilities 18 Dec-20 Dec

• Class M 25/15/05
• Class X 05/05/01
• Proton 05/05/01
• PCAF yellow

IV. Penticton 10.7 cm Flux

• Observed 17 Dec 081
• Predicted 18 Dec-20 Dec 075/075/075
• 90 Day Mean 17 Dec 081

V. Geomagnetic A Indices

• Observed Afr/Ap 16 Dec 010/011
• Estimated Afr/Ap 17 Dec 006/008
• Predicted Afr/Ap 18 Dec-20 Dec 004/005-004/005-006/020

VI. Geomagnetic Activity Probabilities 18 Dec-20 Dec

A. Middle Latitudes

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

B. High Latitudes

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