Status Report

NOAA SEC Report of Solar-Geophysical Activity 25 Oct 2001

By SpaceRef Editor
October 25, 2001
Filed under , ,
:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Oct 25 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 298 Issued at 2200Z on 25 Oct 2001
IA.  Analysis of Solar Active Regions and Activity from  24/2100Z
to 25/2100Z:  Solar Activity was at high levels.  Region 9672
(S18W27) produced a X1/3B flare at 25/1502 UTC with associated Type
II (est. velocity 900 km/s) and Type IV events observed.  SOHO/LASCO
imagery indicate a full halo CME with a plane of sky speed of 884
km/s.  Region 9672 also produced three minor C-class flares.  Region
9678 (N08E20) has grown significantly in the last 24 hours.  This
region has increased in area coverage, spot count, and magnetic
complexity to 300 millionths, 35 spots, and Beta-Gamma-Delta
configuration, respectively.  Other activity on the disc was six
minor C-class flares most of which came from Region 9672 and 9678. 
New Region 9681 (S25E05) and Region 9682 (N09E70) were numbered
IB.  Solar Activity Forecast:  Solar activity is expected to be at
low to moderate levels with a chance for an isolated high condition.
Region 9672 and Region 9678 both have the potential of producing a
major flare.  Both of these regions are active and magnetically
complex.  New Region 9682 is just rotating on to the disc but
already appears to be a large and potentially complex region.
IIA.  Geophysical Activity Summary 24/2100Z to 25/2100Z:
Geomagnetic activity was at quiet to unsettled levels.  Shock arrival
from the two CMEs (M6/2N on 22/1502 UTC and X1/2B on 22/1759 UTC)
occurred at 25/0850 UTC with a sudden impulse of 22 nT recorded on
the Boulder magnetometer.  A north directed Bz component to the
interplanetary magnetic field resulted in only unsettled conditions.
IIB.  Geophysical Activity Forecast:  Geomagnetic activity is
expected to be at quiet to major storm levels.  Quiet to active
levels are expected on day one of the period.  Analysis of the 
X1/3B full halo CME on 25/1502 UTC indicates that shock arrival is
expected late on day two or early on day three of the period.  Shock
arrival is expected to produce unsettled to minor storm levels for
day two and three of the period.  Isolated major storm levels are
possible particularly at higher latitudes.
III.  Event Probabilities 26 Oct-28 Oct
Class M    75/75/75
Class X    35/25/25
Proton     25/15/15
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           25 Oct 239
Predicted   26 Oct-28 Oct  230/225/220
90 Day Mean        25 Oct 196
V.  Geomagnetic A Indices
Observed Afr/Ap 24 Oct  004/003
Estimated Afr/Ap 25 Oct  006/008
Predicted Afr/Ap 26 Oct-28 Oct  008/010-018/020-025/030
VI.  Geomagnetic Activity Probabilities 26 Oct-28 Oct
A.  Middle Latitudes
Active                25/50/50
Minor storm           05/30/30
Major-severe storm    01/15/15
B.  High Latitudes
Active                30/45/45
Minor storm           15/35/35
Major-severe storm    01/20/20

SpaceRef staff editor.