NOAA SEC Report of Solar-Geophysical Activity 23 Jan 2001
:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Jan 23 2230 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 023 Issued at 2200Z on 23 Jan 2001
IA. Analysis of Solar Active Regions and Activity from 22/2100Z
to 23/2100Z: Solar activity was low. Region 9311 (N06W62) produced
today's largest flare, a C4/Sf at 2044Z. This group continues to
show slow growth and has a simple beta magnetic configuration.
Region 9313 (S06E01) continues to show some magnetic complexity but
appears to be decaying slowly. Three new sunspot groups were
assigned today: Region 9322 (S23E00), Region 9323 (S29E03) and
Region 9324 (N10E42). All of these groups were small, simple,
IB. Solar Activity Forecast: Solar activity is expected to be
mostly low, but there is a chance for an isolated M-class event
during the next three days. Regions 9313 and 9311 are the most
likely sources for enhanced solar activity.
IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z:
The geomagnetic field was at quiet to active levels during the past
24 hours. The field was initially quiet. However, an interplanetary
shock was observed at the ACE spacecraft at 1008Z and was followed
by a sudden impulse at Earth at 1047Z. Solar wind behind the shock
showed sheath-like characteristics, with Bz oscillating from
negative to positive. Bz did appear to be trending toward more
strongly negative values near forecast issue time (about -10 nT).
The geomagnetic field responded by becoming unsettled to active.
The greater than 10 MeV protons remain enhanced (at about 2 pfu)
but did not increase with the shock passage.
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be mostly active during the next 12 to 24 hours, with a
chance for isolated storm periods as the current disturbance
continues. A decrease to unsettled to slightly active levels is
expected for the second and third days.
III. Event Probabilities 24 Jan-26 Jan
Class M 35/35/35
Class X 05/05/05
IV. Penticton 10.7 cm Flux
Observed 23 Jan 167
Predicted 24 Jan-26 Jan 165/165/160
90 Day Mean 23 Jan 174
V. Geomagnetic A Indices
Observed Afr/Ap 22 Jan 008/010
Estimated Afr/Ap 23 Jan 018/015
Predicted Afr/Ap 24 Jan-26 Jan 025/020-012/015-012/015
VI. Geomagnetic Activity Probabilities 24 Jan-26 Jan
A. Middle Latitudes
Minor storm 25/15/15
Major-severe storm 20/05/05
B. High Latitudes
Minor storm 20/15/15
Major-severe storm 25/10/05