Joint USAF/NOAA Report of Solar and Geophysical Activity 27 August 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Aug 27 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 239 Issued at 2200Z on 27 Aug 2011
IA. Analysis of Solar Active Regions and Activity from 26/2100Z
to 27/2100Z: Solar activity has been at very low levels for the past
24 hours. There are currently 9 numbered regions on the visible
disk, but only 5 regions have retained their spots. All spotted
regions seem to be either stable or in a decay phase. The largest
flare of the period was a B8 x-ray event, observed at 0446Z, from
Region 1275 (N07W08). A CME was observed in LASCO C2 and STEREO
Behind COR2 imagery. Analysis indicates that the CME is a backsided
event.
IB. Solar Activity Forecast: Solar activity is expected to be at
very low levels with a chance for C-class events for the next three
days (28-30 August). Even though Region 1271 (N16W82) is expected to
rotate off the visible disk in the next 24 hours, it appears old
Region 1267 (S18, L=246) is rotating onto the east limb.
IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z:
The geomagnetic field has been at quiet levels for the past 24 hours.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at quiet to unsettled levels with a chance for active
periods at high latitudes for the next two days (28-29 August), as a
coronal hole high speed stream (CH HSS) moves into a geoeffective
position. Predominantly quiet levels are expected on day three (30
August), as the effects of the CH HSS wane.
III. Event Probabilities 28 Aug-30 Aug
Class M 01/01/01
Class X 01/01/01
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 27 Aug 104
Predicted 28 Aug-30 Aug 100/098/095
90 Day Mean 27 Aug 097
V. Geomagnetic A Indices
Observed Afr/Ap 26 Aug 003/003
Estimated Afr/Ap 27 Aug 003/005
Predicted Afr/Ap 28 Aug-30 Aug 008/008-008/008-005/005
VI. Geomagnetic Activity Probabilities 28 Aug-30 Aug
A. Middle Latitudes
Active 20/20/15
Minor storm 05/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 30/25/15
Minor storm 15/10/01
Major-severe storm 01/01/01