NOAA SEC Report of Solar-Geophysical Activity 20 Dec 2001

:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Dec 20 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 354 Issued at 2200Z on 20 Dec 2001
IA.  Analysis of Solar Active Regions and Activity from  19/2100Z
to 20/2100Z:  Solar activity was low. Region 9742 (N10E13) produced
several C-class events including a C8 flare at 20/0438Z. This region
exhibited impressive flux emergence and spot growth this period,
almost doubling in size and spot count. Most growth was concentrated
in the trailer portions of the region, but mixed polarities were
obvious throughout the spot group. Regions 9741 (N05W21) and 9747
(N12E58) produced occasional minor C-class flares. Moderately
complex Regions 9733 (N12W88) and 9739 (S14W90) are rotating quietly
around the west limb. A large prominence eruption and associated CME
occurred on the SE limb between 19/2344 - 20/0028Z. New Regions 9748
(S11E36), and 9749 (S08E72) were numbered today.
IB.  Solar Activity Forecast:  Solar activity is expected to be at
moderate levels. Region 9742 holds good potential for M-class
activity and is developing potential for a major flare.
IIA.  Geophysical Activity Summary 19/2100Z to 20/2100Z:
The geomagnetic field was quiet.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be quiet to unsettled. Periods of unsettled conditions
are likely on days two and three as a large southern coronal hole
moves into a geoeffectively favorable position.
III.  Event Probabilities 21 Dec-23 Dec
Class M    60/60/60
Class X    10/10/10
Proton     05/05/05
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           20 Dec 221
Predicted   21 Dec-23 Dec  215/215/215
90 Day Mean        20 Dec 218
V.  Geomagnetic A Indices
Observed Afr/Ap 19 Dec  005/009
Estimated Afr/Ap 20 Dec  005/006
Predicted Afr/Ap 21 Dec-23 Dec  008/008-008/008-010/008
VI.  Geomagnetic Activity Probabilities 21 Dec-23 Dec
A.  Middle Latitudes
Active                20/20/25
Minor storm           05/05/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                20/25/25
Minor storm           05/05/05
Major-severe storm    01/01/01