Joint USAF/NOAA Report of Solar and Geophysical Activity 4 Oct 2002

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 277 Issued at 2200Z on 04 Oct 2002

IA. Analysis of Solar Active Regions and Activity from 03/2100Z
to 04/2100Z: Solar activity reached high levels. A total of five
M-class flares were observed this period. Region 137 (S19W20) was
the primary source for this activity, producing four M-class flares,
the largest being an M4/1n at 04/0538Z. A delta configuration was
observed to develop in this region late yesterday, and the region
exhibited frequent flare activity since. Region 139 appears to be
growing quickly as it rotates into view. This region produced an
M1/1f flare with associated Type II sweep (357 km/s) at 04/1255Z,
and also produced several moderate C-class flares. A delta
configuration is obvious and white light areal coverage is nearing
500 millionths. New Region 140 (S07E76) was numbered today.

IB. Solar Activity Forecast: Solar activity is expected to be at
moderate to high levels. Complex Regions 137 and 139 will continue
to produce M-class activity, with increasing likelihood for a major
flare from Region 139 as it continues to develop.

IIA. Geophysical Activity Summary 03/2100Z to 04/2100Z:
The geomagnetic field was at predominantly active to major storm
levels with an isolated severe storm period between 04/00 – 03Z.
Though solar wind speed remains below 450 km/s, the Bz component of
the interplanetary magnetic field was sustained southward for the
entire period, ranging from -2 to -12 nT. The storm was gradually
subsiding by the end of the period.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to range from unsettled to minor storm levels with isolated
major storm periods possible. Transient effects from CMEs observed
early on 3 Oct and again on 4 Oct will likely enhance the disturbed
periods on days two and three. A large, recurrent southern coronal
hole will move into geoeffective position late on day three.

III. Event Probabilities 05 Oct-07 Oct
Class M 60/60/60
Class X 10/10/10
Proton 05/05/05
PCAF green

IV. Penticton 10.7 cm Flux
Observed 04 Oct 158
Predicted 05 Oct-07 Oct 160/170/180
90 Day Mean 04 Oct 179

V. Geomagnetic A Indices
Observed Afr/Ap 03 Oct 022/033
Estimated Afr/Ap 04 Oct 035/045
Predicted Afr/Ap 05 Oct-07 Oct 018/020-015/020-012/015

VI. Geomagnetic Activity Probabilities 05 Oct-07 Oct
A. Middle Latitudes
Active 50/50/40
Minor storm 25/25/20
Major-severe storm 15/15/05
B. High Latitudes
Active 50/50/50
Minor storm 30/30/30
Major-severe storm 20/20/20