NOAA SEC Report of Solar-Geophysical Activity 18 Dec 2000

:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Dec 18 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 353 Issued at 2200Z on 18 Dec 2000
IA.  Analysis of Solar Active Regions and Activity from  17/2100Z
to 18/2100Z:  Solar activity was low. Region 9269 (N11W06) produced
today's largest flare, a C7/Sf at 1111Z. The event was associated
with a relatively slow, full-halo coronal mass ejection as observed
by LASCO imagery. An additional CME occurred, beginning with the
lift-off of a portion of the southern polar crown filament (near
S50E01) at 1824Z. The remainder of today's activity consisted of
numerous C-class events from a variety of regions, including Region
9278 (N09E51) which has rotated more clearly into view as a D-type
sunspot group. New Region 9279 (S11E62) was assigned today.
IB.  Solar Activity Forecast:  Solar activity is expected to be low.
There is a slight chance, however, for an isolated M-class event
from any of regions 9264 (S25W36), 9267 (N08W57), 9276 (S12W85), or
9278 (N09E51).
IIA.  Geophysical Activity Summary 17/2100Z to 18/2100Z:
The geomagnetic field was quiet to unsettled during the past 24
hours.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be mostly unsettled for the next two days. An increase
to active, with a possibility for minor storm levels, is expected on
the third day, in response to today's halo CME event.
III.  Event Probabilities 19 Dec-21 Dec
Class M    35/30/25
Class X    01/01/01
Proton     01/01/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           18 Dec 198
Predicted   19 Dec-21 Dec  195/195/190
90 Day Mean        18 Dec 176
V.  Geomagnetic A Indices
Observed Afr/Ap 17 Dec  006/008
Estimated Afr/Ap 18 Dec  008/010
Predicted Afr/Ap 19 Dec-21 Dec  010/010-010/010-025/030
VI.  Geomagnetic Activity Probabilities 19 Dec-21 Dec
A.  Middle Latitudes
Active                20/20/35
Minor storm           10/10/30
Major-severe storm    01/01/15
B.  High Latitudes
Active                20/20/30
Minor storm           10/10/30
Major-severe storm    01/01/20