:Product: 0925RSGA.txt
:Issued: 2011 Sep 25 2235 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
::::::::::CORRECTED COPY::::::::::
SDF Number 268 Issued at 2200Z on 25 Sep 2011
IA.  Analysis of Solar Active Regions and Activity from  24/2100Z
to 25/2100Z:  Solar activity was high.  Regions 1302 (N12E36) and
1303 (S28W79) each produced three M-class flares.  The largest was
an M7/2N at 25/0450Z.  A partial halo CME was observed at 24/1936Z
in LASCO C2 imagery which was likely associated with the M3 flare
from Region 1302 that occurred at 24/1921Z.  The event had an
associated Type II (1369 km/s) and an approximate plane of sky speed
of 800 km/s using LASCO C3 imagery.  The majority of the ejecta was 
directed off the North East limb.  Two more CMEs were observed at
25/0236Z and 25/0312Z off the Southwest limb in LASCO C2 imagery,
however, they are not expected to be geoeffective.
IB.  Solar Activity Forecast:  Solar activity is expected to continue
at high levels with a chance for isolated X-class flares from Region
1302.
IIA.  Geophysical Activity Summary 24/2100Z to 25/2100Z:
The geomagnetic field was mostly quiet.  At approximately 25/1106Z, 
the IMF Bt increased from 5 nT to 10 nT while the field
density increased to around 7 p/cc at the ACE spacecraft.  A sudden 
impulse (14 nT) was observed in the Boulder magnetometer at 25/1151Z.  
The greater than 10 MeV proton event that began at 23/2255Z, reached 
a peak of 27.3 PFUs at 25/2030Z, and continues to remain above the 
10 PFU threshold.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be at unsettled to minor storm conditions with major
storm periods possible at high latitudes on day 1 (26 September) due
to activity from the CME associated with the M7 flare that occurred
at 24/1320Z.  Mostly unsettled conditions are expected on days 2-3
(27-28 September) due to continued activity from the CME as well as
a possible glancing blow from a weak CME on day 3.  The greater than
10 MeV proton flux is expected to continue to remain above threshold
for the next three days.
III.  Event Probabilities 26 Sep-28 Sep
Class M    80/80/80
Class X    40/40/40
Proton     99/99/80
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           25 Sep 169
Predicted   26 Sep-28 Sep  170/170/170
90 Day Mean        25 Sep 108
V.  Geomagnetic A Indices
Observed Afr/Ap 24 Sep  003/004
Estimated Afr/Ap 25 Sep  007/007
Predicted Afr/Ap 26 Sep-28 Sep  025/030-012/012-008/015
VI.  Geomagnetic Activity Probabilities 26 Sep-28 Sep
A.  Middle Latitudes
Active                45/30/15
Minor storm           20/15/05
Major-severe storm    10/05/01
B.  High Latitudes
Active                45/30/35
Minor storm           25/15/15
Major-severe storm    15/05/05