Joint USAF/NOAA Report of Solar and Geophysical Activity 12 August 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Aug 12 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 224 Issued at 2200Z on 12 Aug 2011
IA. Analysis of Solar Active Regions and Activity from 11/2100Z
to 12/2100Z: Solar activity was very low. Today’s largest event was
a B6 at 11/2309Z which appeared to originate from Region 1263 (N17,
L=296, about a day beyond west limb at the time of the event). The
solar disk now consists of only two spotted regions, Region 1269
(S22E03) and Region 1270 (N23E41). Both groups are very small and
only possess spots without penumbra. A filament eruption in the
northeast quadrant and associated CME were observed, beginning at
about 0336Z. The CME appears to be travelling well out of the
ecliptic plane and is not likely to be geoeffective.
IB. Solar Activity Forecast: Solar activity is expected to be very
low for the next three days.
IIA. Geophysical Activity Summary 11/2100Z to 12/2100Z:
The geomagnetic field was quiet during the past 24 hours. Solar wind
observations of the Phi angle from the ACE spacecraft appeared to
indicate a transition to a negative polarity sector. 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 day 1 (13 August). An
increase to unsettled levels with a chance for active periods is
expected for days 2 and 3 (14-15 August) as a co-rotating
interaction region followed by a negative polarity coronal hole high
speed stream are expected to become weakly geoeffective.
III. Event Probabilities 13 Aug-15 Aug
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 12 Aug 083
Predicted 13 Aug-15 Aug 082/082/080
90 Day Mean 12 Aug 096
V. Geomagnetic A Indices
Observed Afr/Ap 11 Aug 003/006
Estimated Afr/Ap 12 Aug 007/007
Predicted Afr/Ap 13 Aug-15 Aug 007/007-012/012-010/010
VI. Geomagnetic Activity Probabilities 13 Aug-15 Aug
A. Middle Latitudes
Active 25/40/30
Minor storm 05/10/10
Major-severe storm 01/01/01
B. High Latitudes
Active 25/40/35
Minor storm 10/15/15
Major-severe storm 01/05/05