Viewing archive of Sunday, 21 October 2001
Solar activity report
Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2001 Oct 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 294 Issued at 2200Z on 21 Oct 2001IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z Solar activity was at moderate levels. Region 9661
(N14W64) produced an M2/2n flare at 21/1136 UTC with associated
discrete frequency radio bursts. Analysis in white light of this
region also shows a re-emergence of the delta magnetic
configuration. An optically uncorrelated M1 flare was observed at
21/0518 UTC and an associated Type II radio sweep with a shock
velocity of 536 km/s. Using SXI imagery it would appear that this
flare had occurred in Region 9670 (S18E06). Several C-class flares
were produced from Region 9674 (S09E07) during the period.
IB. Solar Activity Forecast
Solar activity is expected to be at
moderate to high levels. Regions 9661 and 9670 remain capable of
producing M-class or isolated major flares.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
The geomagnetic field ranged from quiet to major storm levels. A
strong shock was observed at ACE at 21/1614 UTC. This was followed
by a sudden impulse at 21/1645 UTC (measured as 15 nt on the Boulder
magnetometer). The sudden impulse was followed by minor
(21/1500-1800 UTC) and major (21/1800-2100 UTC) storm levels. BZ
was predominantly negative since the arrival of shock up until the
time of issue of this bulletin.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be at active to major storm levels. The full halo CME
from the X1/2b flare that occurred at 19/1630 UTC from Region 9661
is expected to arrive on the middle of day one of the forecast
period.
III. Event Probabilities 22 Oct to 24 Oct
| Class M | 75% | 75% | 60% |
| Class X | 15% | 15% | 10% |
| Proton | 15% | 15% | 10% |
| PCAF | yellow | ||
IV. Penticton 10.7 cm Flux
Observed 21 Oct 224 Predicted 22 Oct-24 Oct 225/225/215 90 Day Mean 21 Oct 191
V. Geomagnetic A Indices
Observed Afr/Ap 20 Oct 008/010 Estimated Afr/Ap 21 Oct 025/030 Predicted Afr/Ap 22 Oct-24 Oct 030/035-015/020-012/015
VI. Geomagnetic Activity Probabilities 22 Oct to 24 Oct
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 40% | 40% | 15% |
| Minor storm | 40% | 15% | 01% |
| Major-severe storm | 15% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 50% | 50% |
| Minor storm | 50% | 30% | 10% |
| Major-severe storm | 20% | 05% | 01% |
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