Joint USAF/NOAA Report of Solar and Geophysical Activity 8 August 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Aug 08 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 220 Issued at 2200Z on 08 Aug 2011
IA. Analysis of Solar Active Regions and Activity from 07/2100Z
to 08/2100Z: Solar activity was moderate. Region 1263 (N18W68)
produced the largest x-ray flare of the period, a M3/1b at 1810Z.
This event was accompanied by a Type II radio emission (3284 km/s)
and a Tenflare (300 sfu). STEREO-A COR2 imagery indicated a CME
first visible at 1824Z. Extrapolation from later images suggested a
speed of approximately 2010 km/s. Preliminary LASCO C3 image
analysis suggested a speed of 1152 km/s. Region 1263 ended the
period as a Ekc type spot group with beta-gamma-delta magnetic
characteristics. The remaining regions on the disk were small,
simple and relatively quiet.
IB. Solar Activity Forecast: Solar activity is expected to remain
low to moderate for the next three days (09-11 Aug) with Region 1263
being the most likely source of activity. A slight chance for an
isolated X flare and/or proton event remains through the forecast
period.
IIA. Geophysical Activity Summary 07/2100Z to 08/2100Z:
The geomagnetic field was quiet to unsettled as the effects from a
recurrent coronal hole high speed stream began to taper off. Solar
wind speed at the ACE spacecraft was approximately 600 km/s while
the Bz component of the interplanetary magnetic field remained near
zero. There was an enhancement of the greater than 10-MeV protons
in response to the M3 flare mentioned above. The greater than 2 MeV
electron flux at geosynchronous orbit reached high levels during the
period.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be predominantly quiet for the next three days in the
wake of the coronal hole high speed stream. Further analysis of the
CME observed in STEREO and SOHO imagery is underway to determine its
geoeffective potential.
III. Event Probabilities 09 Aug-11 Aug
Class M 55/55/40
Class X 10/10/05
Proton 10/10/10
PCAF Yellow
IV. Penticton 10.7 cm Flux
Observed 08 Aug 102
Predicted 09 Aug-11 Aug 095/085/085
90 Day Mean 08 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 07 Aug 006/007
Estimated Afr/Ap 08 Aug 010/012
Predicted Afr/Ap 09 Aug-11 Aug 010/012-005/005-005/005
VI. Geomagnetic Activity Probabilities 09 Aug-11 Aug
A. Middle Latitudes
Active 15/15/05
Minor storm 05/05/05
Major-severe storm 05/01/01
B. High Latitudes
Active 20/20/11
Minor storm 10/15/06
Major-severe storm 05/05/01