Joint USAF/NOAA Report of Solar and Geophysical Activity 10 August 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Aug 10 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 222 Issued at 2200Z on 10 Aug 2011
IA. Analysis of Solar Active Regions and Activity from 09/2100Z
to 10/2100Z: Solar activity was low. Region 1263 (N17W93) produced
a C6 x-ray flare at 10/1044Z, the largest flare of the past 24
hours. The magnetic complexity and area of Region 1263 decreased
since yesterday and it ended the period as an Ekc type spot group
with beta-gamma characteristics. A Type II (659 km/s) radio
emission occurred at 10/1607Z and was coincident with material
movement and darkening on STEREO-B EUVI imagery in the northeast
quadrant of the solar disk.
IB. Solar Activity Forecast: Solar activity is expected to be low
with a chance for moderate activity as Region 1263 rotates around
the west limb.
IIA. Geophysical Activity Summary 09/2100Z to 10/2100Z:
The geomagnetic field was predominantly quiet with one period of
active levels at mid latitudes. The solar wind speed at the ACE
spacecraft was near 550 km/s. The Bz component of the
interplanetary magnetic field remained within +/- 4 nT of zero. A
discontinuity in density and Phi angle was observed between 10/06Z
and 07Z, when Phi became positive then rotated back to negative over
the next 8 hours. 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 quiet to unsettled on Day 1 (11 Aug) with a slight
chance for active conditions, particularly at high latitudes. The
remaining two days (12-13 Aug) are expected to be predominantly
quiet. Detailed analysis of the CME associated with the X6 flare on
09/0805Z suggests the bulk of the material will not be geoeffective.
A slight disruption in the geomagnetic field may be observed with
shock passage.
III. Event Probabilities 11 Aug-13 Aug
Class M 30/05/01
Class X 10/01/01
Proton 30/05/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 10 Aug 090
Predicted 11 Aug-13 Aug 095/085/085
90 Day Mean 10 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 09 Aug 005/009
Estimated Afr/Ap 10 Aug 007/007
Predicted Afr/Ap 11 Aug-13 Aug 007/007-005/005-005/005
VI. Geomagnetic Activity Probabilities 11 Aug-13 Aug
A. Middle Latitudes
Active 15/15/05
Minor storm 05/05/05
Major-severe storm 01/01/01
B. High Latitudes
Active 25/10/10
Minor storm 10/05/05
Major-severe storm 05/01/01