Report of Solar-Geophysical Activity
Issued: 2005 Aug 25 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 237 Issued at 2200Z on 25 Aug 2005 IA. Analysis of Solar Active Regions and Activity from 24/2100Z to 25/2100Z: Solar activity was high. Region 803 (N12E67) produced an impulsive M6/1n flare at 0440 UTC. The event was associated with a CME off the east limb. Region 800 (N17W35) is currently the largest on the disk but was quiet and stable. New Region 804 (N11E12) emerged on the disk today.
IB. Solar Activity Forecast: Solar activity is expected to be low, but there is a chance for an isolated M-class event from Region 800 or Region 803 during the next three days (26-28 August).
IIA. Geophysical Activity Summary 24/2100Z to 25/2100Z:
The geomagnetic field was predominantly at active to minor storm levels. Today's solar wind data was generally consistent with a coronal hole stream: velocities were elevated and the magnetic field indicated ongoing wave-like fluctuations. The speed gradually declined from initial values around 730 km/s to day-end values around 620 km/s. The greater than 10 MeV proton event that began at 22/2040 UTC ended today at 25/0040 UTC. The peak flux was 330 PFU at
23/1045 UTC. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be predominantly unsettled with a chance for isolated active periods for 26 August. Conditions should be generally unsettled for 27-28 August.
III. Event Probabilities 26 Aug-28 Aug
Class M 20/20/20
Class X 05/05/05
Proton 05/05/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 25 Aug 092
Predicted 26 Aug-28 Aug 095/095/090
90 Day Mean 25 Aug 094
V. Geomagnetic A Indices
Observed Afr/Ap 24 Aug 072/110
Estimated Afr/Ap 25 Aug 020/025
Predicted Afr/Ap 26 Aug-28 Aug 015/015-010/008-010/008 VI. Geomagnetic Activity Probabilities 26 Aug-28 Aug A. Middle Latitudes
Active 40/30/30
Minor storm 20/15/15
Major-severe storm 15/10/10
B. High Latitudes
Active 35/20/20
Minor storm 15/10/10
Major-severe storm 10/05/05