Joint USAF/NOAA Report of Solar and Geophysical Activity 12 Sep 2002

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 255 Issued at 2200Z on 12 Sep 2002

IA.  Analysis of Solar Active Regions and Activity from  11/2100Z
to 12/2100Z:  Solar activity fell to low levels.  The largest event
of the period was a C4/Sf flare at 12/0018 UTC from Region 107
(N11E16).  Region 105 (S08E16) produced several lesser C-class
flares, including an apparent one in progress at the end of the
period.  This region remains the largest on the visible disk.  It's
easternmost spots still retain a beta-gamma-delta magnetic
configuration, while the western spot group appears to have lost
some complexity.  Region 107 continues in a pattern of slow growth
and frequent flare production.  Three new regions were numbered
today, all relatively small and simply structured at present.

IB.  Solar Activity Forecast:  Solar activity is expected to be low
to moderate for the next three days.  M-class activity appears
possible from Regions 105 and 107.

IIA.  Geophysical Activity Summary 11/2100Z to 12/2100Z:
The geomagnetic field was mainly unsettled to active.  One isolated
quiet period was observed at mid-latitudes. Coronal hole high speed
stream effects continued to be the main source of activity.

IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be quiet to active during the first day of the forecast
period, with a gradual reduction towards quiet to unsettled
conditions thereafter.  Greater than 2 MeV electron flux at
geosynchronous orbit may reach high levels during the period.

III.  Event Probabilities 13 Sep-15 Sep
Class M    50/50/50
Class X    05/05/05
Proton     05/05/05
PCAF       green

IV.  Penticton 10.7 cm Flux
Observed           12 Sep 212
Predicted   13 Sep-15 Sep  215/220/225
90 Day Mean        12 Sep 174

V.  Geomagnetic A Indices
Observed Afr/Ap 11 Sep  016/028
Estimated Afr/Ap 12 Sep  013/015
Predicted Afr/Ap 13 Sep-15 Sep  012/012-012/012-008/012

VI.  Geomagnetic Activity Probabilities 13 Sep-15 Sep
A.  Middle Latitudes
Active                25/25/20
Minor storm           05/05/01
Major-severe storm    01/01/01
B.  High Latitudes
Active                30/30/25
Minor storm           05/05/05
Major-severe storm    01/01/01