NOAA SEC Report of Solar-Geophysical Activity 11 Sep 2001

:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Sep 11 2200 UT
# 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 254 Issued at 2200Z on 11 Sep 2001
IA.  Analysis of Solar Active Regions and Activity from  10/2100Z
to 11/2100Z:  Solar activity has been moderate.  Several M-class
flares occurred during the period.  Available optical imagery
suggests that newly numbered Region 9616 (S12E80) rotating on to the
east limb was the source of the largest event (M4/Sf at 11/2036
UTC), as well as an earlier M1 flare at 0704 UTC.  An M2 flare at
11/0111 UTC appears to have emerged from Region 9608 (S27W07),
which, along with Region 9610 (S14E08), also produced several lesser
C-class flares during the period.
IB.  Solar Activity Forecast:  Solar activity is expected to be at
moderate to high levels for the next three days.  All regions
discussed in section 1A above appear to be potential sources for
isolated major flares.
IIA.  Geophysical Activity Summary 10/2100Z to 11/2100Z:
Geomagnetic activity was at quiet to active levels.  Onset of high
speed stream effects appear to have developed from about 11/1200 UTC
through the end of the period.
IIB.  Geophysical Activity Forecast:  Geomagnetic activity is
expected to be at unsettled to active conditions for the first two
days of the forecast period.  A combination of coronal hole high
speed stream effects, and the expected arrival of an interplanetary
shock from CME activity on 9 September, are anticipated to keep
geomagnetic activity elevated for the next two days.  Isolated minor
storm conditions are possible at higher latitudes.  Conditions are
expected to be quiet to unsettled by day three.
III.  Event Probabilities 12 Sep-14 Sep
Class M    80/80/80
Class X    15/15/15
Proton     10/10/10
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           11 Sep 250
Predicted   12 Sep-14 Sep  245/235/235
90 Day Mean        11 Sep 163
V.  Geomagnetic A Indices
Observed Afr/Ap 10 Sep  005/005
Estimated Afr/Ap 11 Sep  011/010
Predicted Afr/Ap 12 Sep-14 Sep  015/020-015/015-012/012
VI.  Geomagnetic Activity Probabilities 12 Sep-14 Sep
A.  Middle Latitudes
Active                20/20/15
Minor storm           15/15/10
Major-severe storm    05/05/05
B.  High Latitudes
Active                30/25/20
Minor storm           20/15/10
Major-severe storm    05/05/05