:Product: 20040921RSGA.txt
:Issued: 2004 Sep 21 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 265 Issued at 2200Z on 21 Sep 2004
IA.  Analysis of Solar Active Regions and Activity from  20/2100Z
to 21/2100Z:  Solar activity was low.  Region 672 (N04W86) produced a
C7.5 flare at 0836Z.  Region 672 will rotate around the west limb on
22 September.  Region 673 (S13W04), the only other sunspot group on
the visible disk, is in a slow decay phase.  No new regions were
numbered.
IB.  Solar Activity Forecast:  Solar activity is expected to be very
low with a slight chance for C-class flares from Region 673 and 672
as it rotates around the west limb.
IIA.  Geophysical Activity Summary 20/2100Z to 21/2100Z:
The geomagnetic field was quiet to unsettled with an isolated active
period between 0300Z to 0600Z.  The active conditions followed a
period of southward IMF Bz.  Solar wind plasma and magnetic field
measurements indicate the presence of a weak coronal hole stream.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be quiet to active with a possibility of reaching minor
storm levels on 22 September.  Active to minor storm periods are
possible on the 22nd due to a weak high speed solar wind stream and
the expected impact of a CME that occurred late on 19 September. 
Levels are expected to return to quiet to unsettled with isolated
active periods on 23-24 September.
III.  Event Probabilities 22 Sep-24 Sep
Class M    05/05/05
Class X    01/01/01
Proton     05/05/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           21 Sep 095
Predicted   22 Sep-24 Sep  090/090/090
90 Day Mean        21 Sep 112
V.  Geomagnetic A Indices
Observed Afr/Ap 20 Sep  008/013
Estimated Afr/Ap 21 Sep  008/010
Predicted Afr/Ap 22 Sep-24 Sep  020/025-010/015-008/010
VI.  Geomagnetic Activity Probabilities 22 Sep-24 Sep
A.  Middle Latitudes
Active                35/30/20
Minor storm           15/10/05
Major-severe storm    05/05/01
B.  High Latitudes
Active                45/35/30
Minor storm           25/20/10
Major-severe storm    10/10/01