Report of Solar-Geophysical Activity
Issued: 2005 Aug 31 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 243 Issued at 2200Z on 31 Aug 2005 IA. Analysis of Solar Active Regions and Activity from 30/2100Z to 31/2100Z: Solar activity was at low levels. Region 803 (N11W13) produced a long duration C2 x-ray event that occurred at 31/1151Z.
This event was followed by a full halo CME that was first observed at 31/1100Z by LASCO imagery. Region 803 continues to show decay and is down to 20 millionths of sunspot area. Region 806 (S17E23) was limited to B-class flare activity and has shown slight decay in sunspot coverage. The magnetic gamma structure remains intact although it has weakened since yesterday. No new regions were numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be at very low to low levels.
IIA. Geophysical Activity Summary 30/2100Z to 31/2100Z:
The geomagnetic field was at quiet to minor storm levels. The elevated conditions ensued following a sustained southward Bz (ranging between -10 and -20 nT) which began just after 31/1000Z.
This activity is believed to be in response to a corotating interaction region. 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 at quiet to minor storm levels. A coronal hole may keep conditions elevated throughout the period. Isolated major storm conditions may be possible on 2 September due to the effects of the full halo CME from the long duration C2 x-ray event that occurred today.
III. Event Probabilities 01 Sep-03 Sep
Class M 15/15/15
Class X 01/01/01
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 31 Aug 084
Predicted 01 Sep-03 Sep 080/080/080
90 Day Mean 31 Aug 094
V. Geomagnetic A Indices
Observed Afr/Ap 30 Aug 003/004
Estimated Afr/Ap 31 Aug 018/032
Predicted Afr/Ap 01 Sep-03 Sep 015/020-025/030-020/025 VI. Geomagnetic Activity Probabilities 01 Sep-03 Sep A. Middle Latitudes
Active 30/45/35
Minor storm 15/25/20
Major-severe storm 05/15/10
B. High Latitudes
Active 35/40/40
Minor storm 20/30/25
Major-severe storm 10/20/15