Joint USAF/NOAA Report of Solar and Geophysical Activity 23 Dec 2007

Product: Report of Solar-Geophysical Activity
Issued: 2007 Dec 23 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 23 Dec 2007

IA. Analysis of Solar Active Regions and Activity from 22/2100Z to 23/2100Z: Solar activity was very low. The visible disk remains spotless.

IB. Solar Activity Forecast: Solar activity is expected to be very low.

IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z: The geomagnetic field was mostly quiet. Solar wind speed slowly declined through the period, with values around 475 km/s at forecast issue time. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels again today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled on 24-25 December, with isolated active periods possible at high latitudes. Quiet conditions are expected to return on 26 December.

III. Event Probabilities 24 Dec-26 Dec

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

IV. Penticton 10.7 cm Flux

• Observed 23 Dec 071
• Predicted 24 Dec-26 Dec 072/072/072
• 90 Day Mean 23 Dec 072

V. Geomagnetic A Indices

• Observed Afr/Ap 22 Dec 007/007
• Estimated Afr/Ap 23 Dec 007/008
• Predicted Afr/Ap 24 Dec-26 Dec 007/008-007/008-005/005

VI. Geomagnetic Activity Probabilities 24 Dec-26 Dec

A. Middle Latitudes

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

B. High Latitudes

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