:Product: 20040913RSGA.txt
:Issued: 2004 Sep 13 2230 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Environment Center and the U.S. Air Force.
#
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 257 Issued at 2200Z on 13 Sep 2004
IA.  Analysis of Solar Active Regions and Activity from  12/2100Z
to 13/2100Z:  Solar activity has been low.  A C1.1 X-ray flare
occurred from Region 667 (S10W85) at 12/2227 UTC.  A C1.0 flare
occurred from Region 669 (S04W81) at 13/0008 UTC.  A C1.4 flare
occurred from Region 672 (N04E22) at 1339 UTC.  No significant
development was observed from regions on the visible disk.  No new
regions were numbered today.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
to moderate.  Isolated M-class flares from Region 672 are possible.
IIA.  Geophysical Activity Summary 12/2100Z to 13/2100Z:
The geomagnetic field has been quiet to unsettled.  A shock passage
was observed at ACE at approximately 13/1935 UTC.  Magnetic field at
ACE was observed to increase significantly to over 20 nT at the time
of the shock arrival at ACE, although Bz remained about zero.  A 24
nT sudden impulse was observed at 2003 UTC.  A 10 MeV proton event
occurred at 2005 UTC in association with the sudden impulse. 
Unsettled magnetic conditions were observed subsequent to the sudden
impulse.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be at minor to major storming levels on 14 September,
due to the effects of a CME arrival.  Conditions should subside to
quiet to active levels on 15 and 16 of September, although isolated
minor storm conditions are possible on those days from the effects
of a geoeffective coronal hole.
III.  Event Probabilities 14 Sep-16 Sep
Class M    20/20/20
Class X    05/05/05
Proton     99/05/05
PCAF       Green
IV.  Penticton 10.7 cm Flux
Observed           13 Sep 118
Predicted   14 Sep-16 Sep  115/115/115
90 Day Mean        13 Sep 112
V.  Geomagnetic A Indices
Observed Afr/Ap 12 Sep  001/004
Estimated Afr/Ap 13 Sep  015/005
Predicted Afr/Ap 14 Sep-16 Sep  040/050-020/030-015/015
VI.  Geomagnetic Activity Probabilities 14 Sep-16 Sep
A.  Middle Latitudes
Active                20/40/35
Minor storm           35/20/10
Major-severe storm    20/10/01
B.  High Latitudes
Active                20/30/40
Minor storm           40/30/20
Major-severe storm    30/20/10