NOAA SEC Report of Solar-Geophysical Activity 23 Sep 2001
:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Sep 23 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 266 Issued at 2200Z on 23 Sep 2001
IA. Analysis of Solar Active Regions and Activity from 22/2100Z
to 23/2100Z: Solar activity was moderate. Region 9632 (S18E32)
produced an M1/Sn flare at 1137 UTC, the day's only M-class event.
That region is still large -- 780 millionths in white light area --
and magnetically complex. Other regions of note are 9622 (N13W45)
and 9628 (S18E12). One new region was born on the disk, Region 9635
(N22E13), a simple bipole.
IB. Solar Activity Forecast: Solar activity is expected to persist
at the moderate level.
IIA. Geophysical Activity Summary 22/2100Z to 23/2100Z:
The geomagnetic field varied from quiet to minor storm levels in the
past 24 hours. A shock passed the ACE spacecraft at about 0800 UTC,
followed by an increase in solar wind radial speed to near 600 km/s.
Periods of active to minor storm levels resulted from this fast
IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be unsettled to active throughout the forecast period.
The current high speed solar wind stream may persist over the next
few days, bringing occasional episodes of minor storm conditions to
III. Event Probabilities 24 Sep-26 Sep
Class M 70/70/70
Class X 10/10/10
IV. Penticton 10.7 cm Flux
Observed 23 Sep 259
Predicted 24 Sep-26 Sep 265/270/270
90 Day Mean 23 Sep 167
V. Geomagnetic A Indices
Observed Afr/Ap 22 Sep 006/010
Estimated Afr/Ap 23 Sep 015/020
Predicted Afr/Ap 24 Sep-26 Sep 010/012-010/018-010/020
VI. Geomagnetic Activity Probabilities 24 Sep-26 Sep
A. Middle Latitudes
Minor storm 10/10/10
Major-severe storm 01/01/01
B. High Latitudes
Minor storm 15/15/15
Major-severe storm 05/05/05