Report of Solar-Geophysical Activity

Issued: 2006 Aug 27 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 239 Issued at 2200Z on 27 Aug 2006

IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity was very low. Region 905 (S06W07) has produced only B-class activity during the past 24 hours.

IB. Solar Activity Forecast: Solar activity is expected to be very low with a chance for C-class activity from Region 905.

IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z:

The geomagnetic field was at quiet to minor storm levels. The solar wind speed increased to about 550 km/s over the past 24 hours due to the coronal hole high speed stream. A minor storm period was observed between 27/1500Z - 27/1800Z as Bz varied between 20 nT and

-15 nt.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be unsettled to active on 28 August. Expect unsettled to active conditions with a chance for isolated minor storm periods on 29 August due to the possible CME associated with the C2 flare observed on 26 August. Further unsettled to active conditions are expected on 30 August.

III. Event Probabilities 28 Aug-30 Aug

Class M 05/05/05

Class X 01/01/01

Proton 01/01/01

PCAF green

IV. Penticton 10.7 cm Flux

Observed 27 Aug 079

Predicted 28 Aug-30 Aug 080/075/075

90 Day Mean 27 Aug 077

V. Geomagnetic A Indices

Observed Afr/Ap 26 Aug 002/003

Estimated Afr/Ap 27 Aug 014/012

Predicted Afr/Ap 28 Aug-30 Aug 010/012-015/018-010/012 VI. Geomagnetic Activity Probabilities 28 Aug-30 Aug A. Middle Latitudes

Active 35/40/35

Minor storm 15/20/15

Major-severe storm 05/05/05

B. High Latitudes

Active 40/50/40

Minor storm 20/30/20

Major-severe storm 10/10/10