NOAA/USAF Report of Solar-Geophysical Activity 24 November 2000

:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Nov 24 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 329 Issued at 2200Z on 24 Nov 2000
IA.  Analysis of Solar Active Regions and Activity from  23/2100Z
to 24/2100Z:  Solar activity is now at high levels. Magnetograms
revealed developing complexity late last period in Region 9236
(N22W07) and a series of significant events followed. The first was
an M1/1n at 23/2328Z with associated Type II sweep (1025km/s) and
CME. At 24/0502Z, an X2/3b flare erupted with strong centimetric
radio bursts including a Tenflare of 2200sfu. This event was also
accompanied by a Type II sweep (1000km/s), a proton event, and a
halo CME. The third significant event from this region was an X2/2b
that occurred at 24/1513Z. This flare was also accompanied by large
centimetric radio bursts, a Type II sweep (1200km/s), proton event,
and a halo CME. This region, at over 500 millionths of sunspot areal
coverage, is magnetically complex and still developing. Region 9231
(S24W74) was mostly stable this period, producing only an isolated
low C-class flare. New region 9242 (N22E68) was numbered today.
IB.  Solar Activity Forecast:  Solar activity is expected to be at
moderate to high levels. Region 9236 continues to develop and is
very capable of continued M-class and  X-class events. Region 8231's
complexity will likely result in occasional C-class events with an
isolated chance of a small M-class flare.
IIA.  Geophysical Activity Summary 23/2100Z to 24/2100Z:
The geomagnetic field was quiet to unsettled with isolated active
conditions observed late in the period. Solar wind data indicates
we've transitioned to a high speed stream over the past eighteen
hours with current solar wind speed ranging 500 to 550km/s. A
greater than 10 MeV proton event began at 24/1520Z and is currently
in progress. A maximum of 84 pfu was reached at 24/1905Z. A greater
than 100 MeV proton event began at 23/1720Z, with a maximum of
1.1pfu observed at 24/1810Z. The initial proton enhancement began
following the X2/3b flare at 0502Z. A second impulse of protons was
evident following the X2/2b at 1513Z.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to be unsettled to active through day one due to high speed
coronal hole flow. The first of a series of CME 's are expected to
impact the field early on day two. As many as four individual CME's
occurring over the past forty hours appeared earthbound. Minor to
major storming is likely on days two and three. Another proton event
is possible should Region 9236 produce an additional major flare.
III.  Event Probabilities 25 Nov-27 Nov
Class M    70/70/70
Class X    40/40/40
Proton     99/80/50
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           24 Nov 197
Predicted   25 Nov-27 Nov  200/200/195
90 Day Mean        24 Nov 174
V.  Geomagnetic A Indices
Observed Afr/Ap 23 Nov  004/007
Estimated Afr/Ap 24 Nov  008/008
Predicted Afr/Ap 25 Nov-27 Nov  015/020-060/070-050/060
VI.  Geomagnetic Activity Probabilities 25 Nov-27 Nov
A.  Middle Latitudes
Active                40/20/20
Minor storm           25/40/40
Major-severe storm    10/40/40
B.  High Latitudes
Active                50/20/20
Minor storm           30/30/30
Major-severe storm    15/50/50