Status Report

NOAA SEC Report of Solar-Geophysical Activity 19 Oct 2001

By SpaceRef Editor
October 19, 2001
Filed under , ,
:Product: Report of Solar-Geophysical Activity
:Issued: 2001 Oct 19 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 292 Issued at 2200Z on 19 Oct 2001
IA.  Analysis of Solar Active Regions and Activity from  18/2100Z
to 19/2100Z:  Solar activity was at high levels.  Region 9661
(N16W35) was very active producing two X class flares.  The first X
class flare was a X1/2b occurred at 19/0105 UTC with an associated
Type II radio sweep (914 km/s).  The second X class flare was a
X1/2b that occurred at 19/1630 UTC with an associated Type II radio
sweep (738 km/s).  SOHO/LASCO imagery shows a full halo CME
associated with both CME events.  A Type IV radio sweep was also
detected with both CME events.  Other activity was centered around
Region 9658 (S14W61). This region produced an M5/1b flare at 19/0943
UTC and several other minor M-class and C-class flares.  New Region
9674 (S08E34) was numbered today.
IB.  Solar Activity Forecast:  Solar activity is expected to be at
moderate to high levels.  Region 9658 and Region 9661 are very
active producing major flares.  There has been very little change in
their characteristics from yesterday, so the potential for a major
flare is remains good.
IIA.  Geophysical Activity Summary 18/2100Z to 19/2100Z:
Geomagnetic activity was quiet to unsettled.  Greater than 10 MeV
proton level was enhanced due to the two CMEs from Region 9661, but
remained just below event threshold.
IIB.  Geophysical Activity Forecast:  Geomagnetic activity is
expected to be at quiet to unsettled conditions for day one  Quiet
to minor storm levels are expected on day two and three with the
possibility for isolated major storm conditions.  Analysis of the
full halo CME (19/0105 UTC from Region 9661) indicated shock arrival
late on day two or early on day three (57-72 hour transit time). 
The shock arrival from the second full halo CME (19/1630 UTC from
Region 9661) is expected to arrive late on day three of the period
(76-81 hour transit time).  Greater than 10 MeV proton level may
exceed event threshold on the first day of the period.   Further
enhancements may occur if major flare activity continues.
III.  Event Probabilities 20 Oct-22 Oct
Class M    75/75/75
Class X    20/20/20
Proton     75/50/20
PCAF       red
IV.  Penticton 10.7 cm Flux
Observed           19 Oct 248
Predicted   20 Oct-22 Oct  250/250/245
90 Day Mean        19 Oct 189
V.  Geomagnetic A Indices
Observed Afr/Ap 18 Oct  002/004
Estimated Afr/Ap 19 Oct  006/008
Predicted Afr/Ap 20 Oct-22 Oct  010/012-025/025-030/035
VI.  Geomagnetic Activity Probabilities 20 Oct-22 Oct
A.  Middle Latitudes
Active                15/55/55
Minor storm           05/30/30
Major-severe storm    01/05/05
B.  High Latitudes
Active                20/55/55
Minor storm           15/30/35
Major-severe storm    05/10/10

SpaceRef staff editor.