NOAA SEC Report of Solar-Geophysical Activity 12 Dec 2001

:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Dec 12 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 346 Issued at 2200Z on 12 Dec 2001
IA.  Analysis of Solar Active Regions and Activity from  11/2100Z
to 12/2100Z:  Solar activity decreased to moderate levels. Region
9733 (N14E18) produced an M3/1n flare at 12/1911 UTC associated with
a 420 sfu Tenflare. This large, complex spot group remained in a
growth phase with a delta magnetic configuration observed within its
northernmost trailer spots. Region 9727 (S21W52) produced occasional
subflares, the largest of which was a C9 at 12/2024 UTC. This region
also grew during the period and remained large and complex with
delta magnetic configurations in its interior and trailer spots.
Region 9736 (S09W55) showed minor growth during the period and
produced isolated C-class subflares. New Region 9738 (S21E67) was
numbered.
IB.  Solar Activity Forecast:  Solar activity is expected to be at
moderate to high levels with isolated, low-level M-class flares
likely. There will also be a chance for a major flare from Regions
9727 or 9733.
IIA.  Geophysical Activity Summary 11/2100Z to 12/2100Z:
Geomagnetic field activity ranged from quiet to minor storm levels.
Unsettled to minor storm levels occurred during 12/0900 - 1200 UTC.
ACE data suggest a solar sector boundary crossing (positive- to
negative-polarity) as the cause for this brief period of increased
activity. Mostly quiet levels occurred during the remainder of the
period.
IIB.  Geophysical Activity Forecast:  Geomagnetic field activity is
expected to be at quiet to unsettled levels during most of the
period. However, brief active periods will be possible during 14 -
15 December due to coronal hole effects. There will be a chance for
a proton flare from Regions 9727 or 9733.
III.  Event Probabilities 13 Dec-15 Dec
Class M    80/80/80
Class X    20/20/20
Proton     20/20/20
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           12 Dec 237
Predicted   13 Dec-15 Dec  220/220/210
90 Day Mean        12 Dec 219
V.  Geomagnetic A Indices
Observed Afr/Ap 11 Dec  003/004
Estimated Afr/Ap 12 Dec  012/012
Predicted Afr/Ap 13 Dec-15 Dec  012/012-012/015-012/015
VI.  Geomagnetic Activity Probabilities 13 Dec-15 Dec
A.  Middle Latitudes
Active                20/20/20
Minor storm           10/10/10
Major-severe storm    01/01/01
B.  High Latitudes
Active                25/25/25
Minor storm           15/15/15
Major-severe storm    05/05/01