:Product: 20040918RSGA.txt
:Issued: 2004 Sep 18 2200 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 262 Issued at 2200Z on 18 Sep 2004
IA.  Analysis of Solar Active Regions and Activity from  17/2100Z
to 18/2100Z:  Solar activity was low. Region 673 (S13E35) produced
the only C-class activity of the period, a single C1 flare at
18/1609Z. Occasional B-class flares were also observed from this
region and from Region 672 (N06W45). Region 673 is a moderate size
beta group that exhibited little change this period. Region 672 has
decayed considerably over the past 48 hours. No other significant
activity or changes were noted.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
to very low. Isolated C-class activity is possible from Regions 672
and 673.
IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field ranged from quiet to minor storm levels with a
period of major storming between 18/0000 - 0300Z. The storm levels
were in response to a prolonged period of southward IMF Bz and solar
wind speeds near 500 km/s. The geomagnetic field was predominantly
quiet to end the period as the solar wind speed declined to 420 km/s
and IMF Bz was sustained north. The greater than 2 MeV electron flux
at geosynchronous orbit was at high levels.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be quiet to unsettled with isolated active periods at
high latitudes.
III.  Event Probabilities 19 Sep-21 Sep
Class M    05/05/05
Class X    01/01/01
Proton     01/01/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           18 Sep 103
Predicted   19 Sep-21 Sep  100/095/095
90 Day Mean        18 Sep 112
V.  Geomagnetic A Indices
Observed Afr/Ap 17 Sep  015/020
Estimated Afr/Ap 18 Sep  015/015
Predicted Afr/Ap 19 Sep-21 Sep  010/012-008/010-005/010
VI.  Geomagnetic Activity Probabilities 19 Sep-21 Sep
A.  Middle Latitudes
Active                25/20/15
Minor storm           10/05/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                30/25/20
Minor storm           15/10/10
Major-severe storm    05/05/05