Joint USAF/NOAA Report of Solar and Geophysical Activity 24 August 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Aug 24 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 236 Issued at 2200Z on 24 Aug 2011
IA. Analysis of Solar Active Regions and Activity from 23/2100Z
to 24/2100Z: Solar activity was low. The largest event in the last
24 hours was a C1/Sf event that originated from Region 1271 (N17W42)
at 24/1633Z. This region has shown separation and penumbral decay in
its intermediate spots. A back-sided, partial halo CME was observed
at 24/0027Z. All other numbered regions on the disk showed various
amounts of decay.
IB. Solar Activity Forecast: Solar activity is expected to be very
low to low with a slight chance for an M-class event from Region
1271 for the next three days (25-27 August).
IIA. Geophysical Activity Summary 23/2100Z to 24/2100Z:
The geomagnetic field was quiet to unsettled.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be quiet for the next two days (25-26 August). Activity
is expected to increase to quiet to unsettled on day three (27
August) due to a recurring coronal hole.
III. Event Probabilities 25 Aug-27 Aug
Class M 10/10/10
Class X 01/01/01
Proton 01/01/01
PCAF Green
IV. Penticton 10.7 cm Flux
Observed 24 Aug 104
Predicted 25 Aug-27 Aug 110/110/115
90 Day Mean 24 Aug 097
V. Geomagnetic A Indices
Observed Afr/Ap 23 Aug 008/009
Estimated Afr/Ap 24 Aug 006/007
Predicted Afr/Ap 25 Aug-27 Aug 005/005-005/005-007/010
VI. Geomagnetic Activity Probabilities 25 Aug-27 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 01/01/10
Major-severe storm 01/01/01

Photo Credit: Ryan Wallace
Twilight glow as the first sunrise of 2011-12 approaches.