:Product: 0825RSGA.txt
:Issued: 2011 Aug 25 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 237 Issued at 2200Z on 25 Aug 2011
IA.  Analysis of Solar Active Regions and Activity from  24/2100Z
to 25/2100Z:  Solar activity was at very low levels. Region 1271
(N17W56) decayed in area and spot count, but developed a Delta
magnetic configuration in the large leader spot. The region produced
numerous low-level B-class events. Three new regions were numbered
during the period. In the western hemisphere, new Region 1278
(N16W40) emerged as a simple 4-spot bi-polar group. On the eastern
limb, new Region 1277 (N17E62) and new Region 1279 (N14E75) both
rotated onto the disk as large, uni-polar H-type groups. Region 1277
produced a B9 x-ray event at 25/0702Z while Region 1279 produced
another B9 x-ray event at 25/1652Z. The SOHO LASCO satellite
observed a slow-moving CME off the east limb, first observed in C2
imagery at 25/0856Z with an estimated plane-of-sky speed of 420
km/s.  This CME does not appear to have an Earthward directed
component.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
with a slight chance for an M-class event all three days (26 - 28
August).
IIA.  Geophysical Activity Summary 24/2100Z to 25/2100Z:
The geomagnetic field was at quiet levels. Observations from the ACE
spacecraft indicated a steady decline in solar wind velocity during
the period from about 500 km/s to near 400 km/s.  The Bz component
of the interplanetary magnetic field did not vary much beyond +/- 4
nT while the phi angle remained negative (toward) throughout the
period.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to remain at quiet levels for days one and two (26 - 27
August). By day three (28 August), activity levels are expected to
increase to quiet to unsettled, with isolated active periods, due to
a geoeffective, recurrent coronal hole high speed stream.
III.  Event Probabilities 26 Aug-28 Aug
Class M    10/10/10
Class X    01/01/01
Proton     01/01/01
PCAF       Green
IV.  Penticton 10.7 cm Flux
Observed           25 Aug 104
Predicted   26 Aug-28 Aug  110/115/115
90 Day Mean        25 Aug 097
V.  Geomagnetic A Indices
Observed Afr/Ap 24 Aug  005/006
Estimated Afr/Ap 25 Aug  005/005
Predicted Afr/Ap 26 Aug-28 Aug  005/005-005/005-007/010
VI.  Geomagnetic Activity Probabilities 26 Aug-28 Aug
A.  Middle Latitudes
Active                15/15/20
Minor storm           01/01/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                15/15/30
Minor storm           01/01/15
Major-severe storm    01/01/01