Joint USAF/NOAA Report of Solar and Geophysical Activity 7 September 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Sep 07 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Weather Prediction Center and the U.S. Air Force.
#
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 250 Issued at 2200Z on 07 Sep 2011
IA. Analysis of Solar Active Regions and Activity from 06/2100Z
to 07/2100Z: Solar activity was high. Region 1283 (N14W32) produced
another major flare, an X2/2b at 06/2220Z. The X2 flare was
associated with Types II and IV radio sweeps, a 740 sfu Tenflare and
an Earth-directed halo CME. The CME had an estimated speed of around
800 km/s, based on STEREO-A COR2 images, with the bulk of mass
directed north of the ecliptic plane. Region 1283 maintained a weak
magnetic delta in the north-central portion of the group and was
classified as a Dai-type with a beta-gamma-delta magnetic
configuration. No new regions were numbered.
IB. Solar Activity Forecast: Solar activity is expected to be
moderate during the period (08 – 10 September) with a chance for
another X-class flare from Region 1283.
IIA. Geophysical Activity Summary 06/2100Z to 07/2100Z:
Geomagnetic field activity was at mostly quiet levels. A proton flux
enhancement at greater than 100 MeV and greater than 10 MeV began
around 06/2300Z at geosynchronous orbit in the wake of the X2 flare
mentioned above. The greater than 2 MeV electron flux at
geosynchronous orbit reached high levels during the period.
IIB. Geophysical Activity Forecast: Geomagnetic activity is
expected to be at mostly quiet levels on day 1 (08 September). An
increase to unsettled levels, with a chance for active levels, is
expected late on day 2 (09 September) due to a CME arrival. A
further increase to unsettled to active levels, with a chance for
minor storm levels, is expected on day 3 (10 September) as the CME
passage continues. There will be a chance for a greater than 10 MeV
proton event at geosynchronous orbit during the period.
III. Event Probabilities 08 Sep-10 Sep
Class M 75/75/75
Class X 30/30/30
Proton 30/30/30
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 07 Sep 113
Predicted 08 Sep-10 Sep 110/105/100
90 Day Mean 07 Sep 098
V. Geomagnetic A Indices
Observed Afr/Ap 06 Sep 005/007
Estimated Afr/Ap 07 Sep 005/005
Predicted Afr/Ap 08 Sep-10 Sep 005/005-010/005-020/018
VI. Geomagnetic Activity Probabilities 08 Sep-10 Sep
A. Middle Latitudes
Active 10/25/30
Minor storm 01/10/25
Major-severe storm 01/01/05
B. High Latitudes
Active 15/30/40
Minor storm 01/15/30
Major-severe storm 01/01/10