Viewing archive of Thursday, 20 December 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 Dec 20 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 354 Issued at 2200Z on 20 Dec 2001

IA. Analysis of Solar Active Regions and Activity from 19-2100Z to 20-2100Z

Solar activity was low. Region 9742 (N10E13) produced several C-class events including a C8 flare at 20/0438Z. This region exhibited impressive flux emergence and spot growth this period, almost doubling in size and spot count. Most growth was concentrated in the trailer portions of the region, but mixed polarities were obvious throughout the spot group. Regions 9741 (N05W21) and 9747 (N12E58) produced occasional minor C-class flares. Moderately complex Regions 9733 (N12W88) and 9739 (S14W90) are rotating quietly around the west limb. A large prominence eruption and associated CME occurred on the SE limb between 19/2344 - 20/0028Z. New Regions 9748 (S11E36), and 9749 (S08E72) were numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be at moderate levels. Region 9742 holds good potential for M-class activity and is developing potential for a major flare.
IIA. Geophysical Activity Summary 19-2100Z to 20-2100Z
The geomagnetic field was quiet.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to unsettled. Periods of unsettled conditions are likely on days two and three as a large southern coronal hole moves into a geoeffectively favorable position.
III. Event Probabilities 21 Dec to 23 Dec
Class M60%60%60%
Class X10%10%10%
IV. Penticton 10.7 cm Flux
  Observed       20 Dec 221
  Predicted   21 Dec-23 Dec  215/215/215
  90 Day Mean        20 Dec 218
V. Geomagnetic A Indices
  Observed Afr/Ap 19 Dec  005/009
  Estimated     Afr/Ap 20 Dec  005/006
  Predicted    Afr/Ap 21 Dec-23 Dec  008/008-008/008-010/008
VI. Geomagnetic Activity Probabilities 21 Dec to 23 Dec
A. Middle Latitudes
Minor storm05%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm05%05%05%
Major-severe storm01%01%01%

All times in UTC

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