Joint USAF/NOAA Report of Solar and Geophysical Activity 12 Sep 2005
Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Environment Center and the U.S. Air Force.
Updated 2005 Sep 12 2204 UTC
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 255 Issued at 2200Z on 12 Sep 2005
IA. Analysis of Solar Active Regions and Activity from 11/2100Z to 12/2100Z: Solar activity was at high levels. Region 808 (S11E17) produced four M-class flares. The largest of these was a M6.1/2f flare at 12/0903 UTC. This flare had an associated tenflare of 980 sfu. Region 808 has decayed in penumbral area on the eastern and western most ends of the sunspot region. Area has decayed to approximately 840 millionths; however, the region still exhibits a beta-gamma-delta magnetic configuration.
IB. Solar Activity Forecast: Solar activity is expected to be moderate to high.
IIA. Geophysical Activity Summary 11/2100Z to 12/2100Z: The geomagnetic field was at active to major storm levels. A shock was observed by the ACE spacecraft at approximately 12/0600 UTC. Solar wind speed at ACE increased to over a thousand km/s; however, the IMF Bz never went lower than -12 nT. Minor to major storm levels occurred at all latitudes following the shock. Solar wind speed gradually declined to near 800 km/s by the end of the period. The greater than 10 MeV proton event remains in progress, but has now declined to near 10 pfu. The greater than 2 MeV electron flux at geosynchronous orbit was at high levels today.
IIB. Geophysical Activity Forecast: The geomagnetic field is expected to range from unsettled to major storm levels. Solar wind speed remains very high and further transient flow is expected on 13 September. Barring any further CME activity from Region 808, the geomagnetic field should return to unsettled to active periods by 15 September.
III. Event Probabilities 13 Sep-15 Sep
- Class M 80/75/70
- Class X 60/50/40
- Proton 99/50/40
- PCAF in progress
IV. Penticton 10.7 cm Flux
- Observed 12 Sep 118
- Predicted 13 Sep-15 Sep 115/110/110
- 90 Day Mean 12 Sep 092
V. Geomagnetic A Indices
- Observed Afr/Ap 11 Sep 053/105
- Estimated Afr/Ap 12 Sep 045/060
- Predicted Afr/Ap 13 Sep-15 Sep 025/035-020/025-015/020
VI. Geomagnetic Activity Probabilities 13 Sep-15 Sep
A. Middle Latitudes
- Active 35/30/30
- Minor storm 20/20/15
- Major-severe storm 15/10/05
B. High Latitudes
- Active 20/35/30
- Minor storm 35/20/20
- Major-severe storm 20/15/10
