Report of Solar-Geophysical Activity

Issued: 2005 Dec 26 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 360 Issued at 2200Z on 26 Dec 2005 IA. Analysis of Solar Active Regions and Activity from 25/2100Z to 26/2100Z: Solar activity decreased to very low levels. The six spotted regions on the visible disk were limited to minor B-class activity. Region 843 (N12E67) was numbered today.

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

IIA. Geophysical Activity Summary 25/2100Z to 26/2100Z:

The geomagnetic field was at quiet levels today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on 27 December. A recurrent high speed coronal hole stream is expected to become geoeffective on 28 December and continue through 29 December.

Unsettled to active conditions with isolated high latitude minor storm periods are expected to accompany the high speed stream.

III. Event Probabilities 27 Dec-29 Dec

Class M 05/05/05

Class X 01/01/01

Proton 01/01/01

PCAF green

IV. Penticton 10.7 cm Flux

Observed 26 Dec 093

Predicted 27 Dec-29 Dec 095/095/100

90 Day Mean 26 Dec 084

V. Geomagnetic A Indices

Observed Afr/Ap 25 Dec 005/006

Estimated Afr/Ap 26 Dec 002/008

Predicted Afr/Ap 27 Dec-29 Dec 010/010-012/015-012/015 VI. Geomagnetic Activity Probabilities 27 Dec-29 Dec A. Middle Latitudes

Active 20/25/25

Minor storm 05/10/10

Major-severe storm 01/05/05

B. High Latitudes

Active 25/35/35

Minor storm 10/15/15

Major-severe storm 05/10/10