:Product: 0928RSGA.txt
:Issued: 2011 Sep 28 2205 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 271 Issued at 2200Z on 28 Sep 2011
IA.  Analysis of Solar Active Regions and Activity from  27/2100Z
to 28/2100Z:  Solar activity was moderate. Region 1302 (N13W04)
produced an M1/1n flare at 28/1328Z. Region 1302 also produced a
C9/1n flare at 28/1232Z associated with a 390 sfu Tenflare.
Occasional C-class flares were observed during the period. New
Region 1307 (N14E75) was numbered today.
IB.  Solar Activity Forecast:  Solar activity is expected to be low
with a chance for an isolated M- and  X-flare from Region 1302.
IIA.  Geophysical Activity Summary 27/2100Z to 28/2100Z:
The geomagnetic field ranged from unsettled to minor storm levels,
due to substorming. The greater than 10 MeV protons at
geosynchronous orbit were enhanced during the period. Wind speeds
reached 548 km/s at 27/2132Z and decreased to approximately 450 km/s
at 28/1716Z.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be quiet to unsettled, with isolated active levels at
high latitudes, on day one (29 September). Predominantly quiet
levels are expected on days two and three (30 September-01 October).
III.  Event Probabilities 29 Sep-01 Oct
Class M    50/50/50
Class X    30/30/30
Proton     10/10/10
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           28 Sep 133
Predicted   29 Sep-01 Oct  130/130/125
90 Day Mean        28 Sep 109
V.  Geomagnetic A Indices
Observed Afr/Ap 27 Sep  022/030
Estimated Afr/Ap 28 Sep  014/022
Predicted Afr/Ap 29 Sep-01 Oct  008/012-005/005-008/008
VI.  Geomagnetic Activity Probabilities 29 Sep-01 Oct
A.  Middle Latitudes
Active                15/05/15
Minor storm           01/01/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                20/10/20
Minor storm           05/01/01
Major-severe storm    01/01/01