Report of Solar-Geophysical Activity

Issued: 2006 Aug 20 2218 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 232 Issued at 2200Z on 20 Aug 2006

IA. Analysis of Solar Active Regions and Activity from 19/2100Z to 20/2100Z: Solar activity was low. Region 904 (S14W72) produced multiple B-class and C-class flares including a C2.9 flare at 20/1632Z. This region also produced a long duration C-class flare with maximum occurring at 20/1346Z, An associated CME was observed on the southwest limb in LASCO imagery at 20/1442Z. The plane-of-sky speed was estimated to be 300 km/s.

IB. Solar Activity Forecast: Solar activity is expected to be low with the possibility of an isolated M-class flare from Region 904.

IIA. Geophysical Activity Summary 19/2100Z to 20/2100Z:

The geomagnetic field has been at quiet to major storm levels. There was a period of severe storm levels from 1200 - 1800Z recorded on

the College, AK magnetometer. This activity is likely due to the

full halo CME observed on 16 August.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be quiet to unsettled for the forecast period, 21 - 23 August. Due to the relatively slow speed of the CME mentioned above, no effects are anticipated during this forecast period.

III. Event Probabilities 21 Aug-23 Aug

Class M 10/10/01

Class X 01/01/01

Proton 01/01/01

PCAF green

IV. Penticton 10.7 cm Flux

Observed 20 Aug 088

Predicted 21 Aug-23 Aug 090/090/085

90 Day Mean 20 Aug 077

V. Geomagnetic A Indices

Observed Afr/Ap 19 Aug 021/038

Estimated Afr/Ap 20 Aug 022/025

Predicted Afr/Ap 21 Aug-23 Aug 008/012-006/005-006/005 VI. Geomagnetic Activity Probabilities 21 Aug-23 Aug A. Middle Latitudes

Active 30/30/30

Minor storm 15/15/15

Major-severe storm 05/01/01

B. High Latitudes

Active 35/30/30

Minor storm 20/15/15

Major-severe storm 05/01/01