Report of Solar-Geophysical Activity

Issued: 2005 Dec 19 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 353 Issued at 2200Z on 19 Dec 2005 IA. Analysis of Solar Active Regions and Activity from 18/2100Z to 19/2100Z: Solar activity was very low. Today's activity consisted of a few B-class events from Region 837 (S10W06), which has developed into the largest sunspot group on the disk at 200 millionths. No new regions were numbered today.

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

IIA. Geophysical Activity Summary 18/2100Z to 19/2100Z:

The geomagnetic field ranged from quiet to active. Solar wind speed showed an increase up to about 470 km/s after 1700Z, which was accompanied by a southward interplanetary magnetic field. The solar wind speed appeared to be slowly declining after 2030Z.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled during the next three days (20 -

22 December).

III. Event Probabilities 20 Dec-22 Dec

Class M 10/10/10

Class X 01/01/01

Proton 01/01/01

PCAF green

IV. Penticton 10.7 cm Flux

Observed 19 Dec 090

Predicted 20 Dec-22 Dec 090/090/085

90 Day Mean 19 Dec 083

V. Geomagnetic A Indices

Observed Afr/Ap 18 Dec 002/003

Estimated Afr/Ap 19 Dec 002/005

Predicted Afr/Ap 20 Dec-22 Dec 005/008-005/008-005/008 VI. Geomagnetic Activity Probabilities 20 Dec-22 Dec A. Middle Latitudes

Active 15/15/15

Minor storm 05/05/05

Major-severe storm 01/01/01

B. High Latitudes

Active 25/25/25

Minor storm 05/05/05

Major-severe storm 01/01/01