:Product: 0811RSGA.txt
:Issued: 2011 Aug 11 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 223 Issued at 2200Z on 11 Aug 2011
IA.  Analysis of Solar Active Regions and Activity from  10/2100Z
to 11/2100Z:  Solar activity was low.  Region 1263 (N17, L=301)
produced a C6 x-ray flare from beyond the west limb.  New regions
1269 (S22E17) and 1270 (S23E54) were numbered today; both are small
and magnetically simple.  A CME was observed on the west limb,
evident in SOHO/LASCO C2 imagery at 11/1036Z.  Material movement and
subsequent darkening was observed in STEREO-A EUV imagery beginning
at approximately 11/1005Z.  This CME is not expected to be
geoeffective.
IB.  Solar Activity Forecast:  Solar activity is expected to be very
low to low.  There is a chance for a C class x-ray event throughout
the period.
IIA.  Geophysical Activity Summary 10/2100Z to 11/2100Z:
The geomagnetic field was quiet.  Solar wind speed at the ACE
spacecraft continued to decline and ended the period near 400 km/s. 
The Phi angle briefly switched to negative between 11/10Z and
11/12Z.  The Bz component of the interplanetary magnetic field
remained around zero.  A shock was observed in the STEREO-A beacon
data at roughly 11/0600Z.  This is most likely the arrival of the 09
August CME from Region 1263. The greater than 2 MeV electron flux at
geosynchronous orbit was at high levels throughout the period.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be predominantly quiet for the next three days (12-14
August).
III.  Event Probabilities 12 Aug-14 Aug
Class M    05/05/05
Class X    01/01/01
Proton     01/01/01
PCAF       Green
IV.  Penticton 10.7 cm Flux
Observed           11 Aug 084
Predicted   12 Aug-14 Aug  085/085/090
90 Day Mean        11 Aug 096
V.  Geomagnetic A Indices
Observed Afr/Ap 10 Aug  008/007
Estimated Afr/Ap 11 Aug  005/004
Predicted Afr/Ap 12 Aug-14 Aug  005/005-005/005-005/005
VI.  Geomagnetic Activity Probabilities 12 Aug-14 Aug
A.  Middle Latitudes
Active                15/05/05
Minor storm           05/05/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                20/10/20
Minor storm           10/05/10
Major-severe storm    05/01/05