Report of Solar-Geophysical Activity

Issued: 2006 Aug 16 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 228 Issued at 2200Z on 16 Aug 2006

IA. Analysis of Solar Active Regions and Activity from 15/2100Z to 16/2100Z: Solar activity was low. Region 904 (S12W15) produced a long duration C3.6/Sf flare with maximum occurring at 16/1617Z. An associated partial, or possibly full, halo CME was first observed on LASCO imagery at 16/1630Z. The estimated plane-of-sky speed was about 800 km/s. A Type IV radio sweep was associated with this event. In spite of today's activity, Region 904 has generally remained unchanged during the past 24 hours.

IB. Solar Activity Forecast: Solar activity is expected to be very low to low. There is a chance for an isolated M-class flare.

IIA. Geophysical Activity Summary 15/2100Z to 16/2100Z:

The geomagnetic field was quiet. 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 predominantly quiet on 17-18 August. Unsettled to active conditions, with isolated periods of minor storm levels, are expected on 19 August due to effects of the above-mentioned CME.

III. Event Probabilities 17 Aug-19 Aug

Class M 20/20/20

Class X 01/01/01

Proton 01/01/01

PCAF green

IV. Penticton 10.7 cm Flux

Observed 16 Aug 086

Predicted 17 Aug-19 Aug 086/090/090

90 Day Mean 16 Aug 077

V. Geomagnetic A Indices

Observed Afr/Ap 15 Aug 002/003

Estimated Afr/Ap 16 Aug 003/005

Predicted Afr/Ap 17 Aug-19 Aug 005/005-005/005-025/025 VI. Geomagnetic Activity Probabilities 17 Aug-19 Aug A. Middle Latitudes

Active 15/15/35

Minor storm 05/05/20

Major-severe storm 01/01/10

B. High Latitudes

Active 15/15/35

Minor storm 10/10/25

Major-severe storm 01/01/15