NOAA SEC Report of Solar-Geophysical Activity 30 Dec 2001

:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Dec 30 2210 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 364 Issued at 2200Z on 30 Dec 2001
IA.  Analysis of Solar Active Regions and Activity from  29/2100Z
to 30/2100Z:  Solar activity has been moderate.  Early in the period,
newly numbered Region 9767 (S23E73) produced an M2/1f event at
29/2256 UTC.  This region is the likely source of the X-class flare
and CME activity of 28 December, and has now rotated into view.  The
region appears to be of significant size and magnetic complexity,
but is current location near the east limb prevents a full analysis
of it's characteristics.  Other activity during the same period
included a long duration M1 x-ray enhancement during 29/1950-2355
UTC, with an associated west limb CME evident in LASCO imagery,
though appearing to lack any significant earth-directed component. 
Other regions on the visible disk were mostly quiescent, with a few
minor C-class events observed.  An additional new region was also
numbered today, Region 9766 (N05E62).
IB.  Solar Activity Forecast:  Solar activity is expected to continue
at predominantly moderate levels, with a fair chance for isolated
major flare events during the next three days.
IIA.  Geophysical Activity Summary 29/2100Z to 30/2100Z:
Geomagnetic field activity has been quiet to active.  Most of the
period was dominated by ongoing effects from yesterday's shock
passage, with an extended period of southward IMF producing active
conditions during 30/0300-0900 UTC.  Late in the period, an
additional shock passage was observed at the ACE satellite at
30/1932 UTC, followed by a sudden impulse of 27 nT observed at
Boulder at 30/2010 UTC.  This event is presumed to be an early
arrival of effects from the powerful X-class event of 28 December. 
The greater than 10 MeV proton flux at geosynchronous orbit has
fluctuated near the event threshold value of 10 pfu for most of the
day, though now appears to be undergoing some enhancement due to the
recent shock passage.  As a result of near-threshold activity, a 10
MeV proton event has been in progress since 30/0245 UTC.
IIB.  Geophysical Activity Forecast:  With the arrival of the most
recent shock passage, geomagnetic field conditions are expected to
be unsettled to active, with minor storm conditions possible during
the first day of the forecast period.  An enhancement of activity
due to additional shock effects are also possible within the first
two days, due to expected effects from the west limb CME of 29
December.  Predominantly unsettled and quiet conditions are expected
thereafter as shock passage effects wane.  The 10 MeV proton event
in progress is expected to end within the next 12-24 hours.
III.  Event Probabilities 31 Dec-02 Jan
Class M    75/75/75
Class X    15/15/15
Proton     50/10/10
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           30 Dec 247
Predicted   31 Dec-02 Jan  250/250/245
90 Day Mean        30 Dec 225
V.  Geomagnetic A Indices
Observed Afr/Ap 29 Dec  013/010
Estimated Afr/Ap 30 Dec  018/018
Predicted Afr/Ap 31 Dec-02 Jan  020/020-015/015-012/010
VI.  Geomagnetic Activity Probabilities 31 Dec-02 Jan
A.  Middle Latitudes
Active                30/20/15
Minor storm           20/10/05
Major-severe storm    05/01/01
B.  High Latitudes
Active                35/25/15
Minor storm           25/15/05
Major-severe storm    05/01/01