Report of Solar-Geophysical Activity
Issued: 2005 Sep 15 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 258 Issued at 2200Z on 15 Sep 2005 IA. Analysis of Solar Active Regions and Activity from 14/2100Z to 15/2100Z: Solar activity was high. Region 808 (S11W22) produced an X1.1/2n flare at 15/0838 UTC with an associated 450 sfu Tenflare.
This region was also responsible for several C and low M-class flares throughout the period. Region 808 has changed very little in the last 24 hours and retains a beta-gamma-delta magnetic configuration.
IB. Solar Activity Forecast: Solar activity is expected to continue at moderate to high levels. Region 808 is expected to continue to produce M-class activity and still has the potential to produce an isolated X-flare.
IIA. Geophysical Activity Summary 14/2100Z to 15/2100Z:
The geomagnetic field was at quiet to severe storm levels.
Geomagnetic storming occurred in response to the arrival of a CME associated with the double peak X-flare on 13 September. A 29 nT sudden impulse was observed in the Boulder magnetometer at 15/0907 UTC. Solar wind speed at ACE rose from approximately 600 km/s to near 900 km/s. The most disturbed periods occurred between 12 and 18 UTC following periods of southward Bz to near -15 nT. The greater than 10 MeV proton flux increased during the shock passage to 235 pfu before declining to around 13 pfu by the end of the period. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels today.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at unsettled to minor storm levels with the possibility of isolated major storm periods. Conditions should decrease to quiet to unsettled on 17 and 18 September.
III. Event Probabilities 16 Sep-18 Sep
Class M 70/65/60
Class X 50/40/30
Proton 50/40/30
PCAF yellow
IV. Penticton 10.7 cm Flux
Observed 15 Sep 119
Predicted 16 Sep-18 Sep 115/110/110
90 Day Mean 15 Sep 092
V. Geomagnetic A Indices
Observed Afr/Ap 14 Sep 013/025
Estimated Afr/Ap 15 Sep 025/050
Predicted Afr/Ap 16 Sep-18 Sep 018/025-008/015-008/010 VI. Geomagnetic Activity Probabilities 16 Sep-18 Sep A. Middle Latitudes
Active 35/20/20
Minor storm 20/10/10
Major-severe storm 10/01/01
B. High Latitudes
Active 35/30/25
Minor storm 30/15/10
Major-severe storm 15/05/01