Joint USAF/NOAA Report of Solar and Geophysical Activity 7 Sep 2002

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 250 Issued at 2200Z on 07 Sep 2002

IA.  Analysis of Solar Active Regions and Activity from  06/2100Z
to 07/2100Z:  Solar activity was low. Only a few C-class flares
occurred. New Region 105 (S06E77) is currently rotating around the
east limb and appears to be the return of old active Region 69 (S08,
L=299). So far the area has not produced significant activity. New
Region 104 (N11E59) was also numbered.

IB.  Solar Activity Forecast:  Solar activity is expected to be low
to moderate. Region 105 is the most likely source of energetic
flares.

IIA.  Geophysical Activity Summary 06/2100Z to 07/2100Z:
The geomagnetic field ranged from quiet to severe storm levels. A
shock in the solar wind was observed by the NASA ACE spacecraft at
07/1609 UTC and was followed by a 7 nT sudden impulse on the Boulder
magnetometer at 07/1638 UTC. This shock is believed to be related to
the eruptive filament and CME which occurred on 05 September. The
greater than 10 MeV proton flux crossed the 10 pfu event threshold
at 07/0440 UTC after a slow rise over the previous 28 hours. Peak
event flux so far was 208 pfu at 07/1650 UTC. Retrospect analysis
suggests that these particles are most likely associated with the
eruptive filament mentioned above rather than a west limb event as
suggested yesterday.

IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be at active to storm levels over the next 24 hours,
becoming quiet to unsettled by 10 September. The greater than 10 MeV
proton event is expected to end by 09 September.

III.  Event Probabilities 08 Sep-10 Sep
Class M    50/50/50
Class X    05/05/05
Proton     75/10/05
PCAF       in progress

IV.  Penticton 10.7 cm Flux
Observed           07 Sep 183
Predicted   08 Sep-10 Sep  190/200/210
90 Day Mean        07 Sep 170

V.  Geomagnetic A Indices
Observed Afr/Ap 06 Sep  006/010
Estimated Afr/Ap 07 Sep  030/055
Predicted Afr/Ap 08 Sep-10 Sep  020/025-010/015-008/010

VI.  Geomagnetic Activity Probabilities 08 Sep-10 Sep
A.  Middle Latitudes
Active                30/25/25
Minor storm           20/15/15
Major-severe storm    15/05/05
B.  High Latitudes
Active                50/30/30
Minor storm           25/20/20
Major-severe storm    15/05/05