Report of Solar-Geophysical Activity
Issued: 2005 Sep 11 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
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SDF Number 254 Issued at 2200Z on 11 Sep 2005 IA. Analysis of Solar Active Regions and Activity from 10/2100Z to 11/2100Z: Solar activity was at high levels. Region 808 (S09E30) produced a long duration X2 major flare at 10/2211Z that had an associated Tenflare of 1600 sfu, a Type IV radio sweep, and a Type II radio sweep with an estimated shock velocity of 1606 km/sec. An associated asymmetrical Earth directed full halo CME was observed on LASCO imagery. Further significant activity included a long duration M3/1f flare that occurred at 11/1312Z. An M3 flare with an associated Type IV radio sweep that occurred at 11/0235Z, and an impulsive M1 flare that occurred at 10/2040Z. Region 808 has shown some fragmentation of the trailing portion of the spot cluster, however this spot group remains very dynamic and complex with the spot area exceeding 1200 millionths. Magnetic analysis continues to depict a very strong delta structure in the dominant central penumbral spot. No new regions were numbered today.
IB. Solar Activity Forecast: Solar activity is expected to be at high levels. Region 808 is expected to continue to produce major flares.
IIA. Geophysical Activity Summary 10/2100Z to 11/2100Z:
The geomagnetic field was at active to severe storm levels today.
The storming periods are most likely due to the passage of a CME from the X6 flare that occurred on 09 September. The greater than 10 MeV proton event that began on 08/0215Z was further enhanced with today's shock passage, and reached a peak flux of 1880 pfu at 11/0425Z. The greater than 100 MeV proton that began at 08/0405Z, reached a peak flux of 8 pfu at 09/1920Z, and ended at 11/0545Z.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at active to major storm levels. Severe storm levels may be possible on 12 September due to the passage of the full halo CME from the X2 major flare that occurred on 10 September. Isolated severe storm conditions may be possible on 13 September due to the continued effects of the ongoing transient flow. Although it most likely will be negligible, a recurrent coronal hole should be geoeffective through the forecast period. The greater than 10 MeV proton event is expected to continue through 13 September.
III. Event Probabilities 12 Sep-14 Sep
Class M 90/85/80
Class X 75/70/65
Proton 99/75/50
PCAF in progress
IV. Penticton 10.7 cm Flux
Observed 11 Sep 110
Predicted 12 Sep-14 Sep 110/110/110
90 Day Mean 11 Sep 091
V. Geomagnetic A Indices
Observed Afr/Ap 10 Sep 015/030
Estimated Afr/Ap 11 Sep 070/100
Predicted Afr/Ap 12 Sep-14 Sep 090/100-050/060-020/030 VI. Geomagnetic Activity Probabilities 12 Sep-14 Sep A. Middle Latitudes
Active 30/50/35
Minor storm 35/30/15
Major-severe storm 35/20/10
B. High Latitudes
Active 25/40/45
Minor storm 40/35/20
Major-severe storm 35/25/15