Status Report

NOAA/USAF Report of Solar-Geophysical Activity 25 November 2000

By SpaceRef Editor
November 25, 2000
Filed under ,
:Product: Report of Solar-Geophysical Activity
:Issued: 2000 Nov 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 330 Issued at 2200Z on 25 Nov 2000
IA.  Analysis of Solar Active Regions and Activity from  24/2100Z
to 25/2100Z:  Solar activity continued at high levels. The period
began with another X-class flare from Region 9236 (N22W20). The
X1/2n flare occurred at 24/2159Z and had associated minor
centimetric radio bursts and a CME. Reports of strong doppler shifts
in the NE-SW filament in Region 9240 (N08E34) were soon followed by
an impressive eruption at 25/0131Z. The eruption included an M8/2N,
long duration ribbon flare with strong radio bursts including a
14000 sfu Tenflare. Strong Type II and IV sweeps also occurred with
this flare and a CME was observed on LASCO imagery. Region 9236
flared again, producing an M3/2n flare and CME at 25/0920Z. The
period ended with an X1/2b from Region 9236 with moderate to strong
radio bursts and Type II sweep (910km/s). It appears that yet
another Earth-directed CME was associated with this event. No
significant new growth was noted in Region 9236 over the past 18
hours, but it continues to produce frequent flares in a complex,
beta-gamma configuration exceeding 600 millionths of white light
IB.  Solar Activity Forecast:  Solar activity is expected to continue
at moderate to high levels. Region 9236 is capable of continued M
and X-class events. A filament has reformed in the vicinity of the
0131Z eruption in Region 9240. If the present pattern continues, we
should see another major event from this region in the next three
IIA.  Geophysical Activity Summary 24/2100Z to 25/2100Z:
The geomagnetic field was quiet to unsettled with isolated active
periods at high latitudes. The greater than 10 MeV proton event that
began at 24/1520Z is still in progress and is currently ranging 12
to 18 pfu. The maximum so far was 93 pfu at 24/1920Z. The greater
than 100 MeV proton event that began at 24/1720Z, ended at 24/1820Z
with a peak flux of 1.1 pfu at 24/1810Z.
IIB.  Geophysical Activity Forecast:  The geomagnetic field is
expected to reach minor to major storm levels early in day one. We
observed as many as six Earth directed CME'S in the last 48 hours,
so minor to major storm levels are expected through the next three
days. Another proton event is possible should Regions 9236 or 9240
produce another major flare.
III.  Event Probabilities 26 Nov-28 Nov
Class M    75/70/60
Class X    50/40/35
Proton     80/50/40
PCAF       yellow
IV.  Penticton 10.7 cm Flux
Observed           25 Nov 202
Predicted   26 Nov-28 Nov  200/195/195
90 Day Mean        25 Nov 175
V.  Geomagnetic A Indices
Observed Afr/Ap 24 Nov  009/009
Estimated Afr/Ap 25 Nov  010/012
Predicted Afr/Ap 26 Nov-28 Nov  060/070-050/060-030/040
VI.  Geomagnetic Activity Probabilities 26 Nov-28 Nov
A.  Middle Latitudes
Active                20/20/50
Minor storm           40/40/30
Major-severe storm    40/40/20
B.  High Latitudes
Active                20/20/40
Minor storm           30/30/30
Major-severe storm    50/50/30

SpaceRef staff editor.