:Product: 1225RSGA.txt
:Issued: 2011 Dec 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 359 Issued at 2200Z on 25 Dec 2011
IA.  Analysis of Solar Active Regions and Activity from  24/2100Z
to 25/2100Z:  Solar activity was moderate.  New Region 1387 (S22W28)
produced a M4/1N flare at 25/1816Z.  This event was accompanied by
Type II (1019 km/s) and Type IV radio emissions.  This region grew
rapidly, ending the period as a Dao type group with Beta magnetic
characteristics.  Coronagraph imagery was not yet available to
determine the characteristics of the CME.  Earlier in the period, a
filament eruption occurred near N21W15.  Analysis of this event
using LASCO imagery indicated a speed near 400 km/s.  Evaluation of
the geoeffective potential of both the flare and filament eruption
is ongoing.
IB.  Solar Activity Forecast:  Solar activity is expected to be
moderate, with a chance for further M-class activity from Region
1387.
IIA.  Geophysical Activity Summary 24/2100Z to 25/2100Z:
The geomagnetic field was quiet.  An enhancement of the 10 MeV proton
flux at the ACE spacecraft was observed following the M4/1N flare
mentioned earlier.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be mosly quiet on Days 1 and 2 (26-27 December).  
Initial predictions are for the CME to arrive late on Day 3 (28
December), bringing unsettled to active levels with a slight chance
for minor storm conditions at high latitudes.  The arrival estimate
will be refined as new data becomes available.
III.  Event Probabilities 26 Dec-28 Dec
Class M    50/50/50
Class X    05/05/05
Proton     05/05/05
PCAF       Green
IV.  Penticton 10.7 cm Flux
Observed           25 Dec 144
Predicted   26 Dec-28 Dec  150/155/155
90 Day Mean        25 Dec 144
V.  Geomagnetic A Indices
Observed Afr/Ap 24 Dec  002/001
Estimated Afr/Ap 25 Dec  000/001
Predicted Afr/Ap 26 Dec-28 Dec  006/005-006/005-007/007
VI.  Geomagnetic Activity Probabilities 26 Dec-28 Dec
A.  Middle Latitudes
Active                05/20/25
Minor storm           01/05/15
Major-severe storm    01/05/05
B.  High Latitudes
Active                15/15/15
Minor storm           10/20/30
Major-severe storm    05/25/40