Joint USAF/NOAA Report of Solar and Geophysical Activity 19 Dec 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 Dec 19 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 353 Issued at 2200Z on 19 Dec 2007

IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity was at very low levels.

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

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z: The geomagnetic field was at quiet to active levels. These elevated conditions were due to a coronal hole high speed stream. Solar wind speed at the ACE spacecraft peaked late yesterday between 18/1900Z and 19/0100Z with maximum values around 700 km/s. Since then solar wind speed has been steadily declining with values around 600 km/s at forecast issue time.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at predominately quiet to unsettled levels. However, there is a chance for isolated active conditions on 20 and 21 December, due to the continued influence of the high speed stream.

III. Event Probabilities 20 Dec-22 Dec

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

IV. Penticton 10.7 cm Flux

• Observed 19 Dec 075
• Predicted 20 Dec-22 Dec 070/070/070
• 90 Day Mean 19 Dec 071

V. Geomagnetic A Indices

• Observed Afr/Ap 18 Dec 011/018
• Estimated Afr/Ap 19 Dec 012/012
• Predicted Afr/Ap 20 Dec-22 Dec 010/010-010/010-008/010

VI. Geomagnetic Activity Probabilities 20 Dec-22 Dec

A. Middle Latitudes

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

B. High Latitudes

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