Viewing archive of Friday, 21 December 2001

Solar activity report

Report of Solar-Geophysical Activity 2001 Dec 21 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 355 Issued at 2200Z on 21 Dec 2001

IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z

Solar activity was low. Region 9742 (N10W03) is the largest and most active group on the visible disk and produced several minor C-class flares. This beta-gamma region continues to grow in spot count, area, and magnetic complexity, and now exceeds 700 millionths of white light area. No remarkable activity or developments were observed in the remaining active regions. New Regions 9750 (S16W64) and 9751 (N04E68) were numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be moderate. Region 9742 has good potential for M-class flares and an isolated chance for a major flare.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
The geomagnetic field was quiet to active. An increase in the solar wind speed began at around 21/1100Z. This increase was accompanied by sustained periods of southward Bz resulting in unsettled to active periods at all latitudes.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to continue at quiet to active levels.
III. Event Probabilities 22 Dec to 24 Dec
Class M60%60%60%
Class X10%10%10%
IV. Penticton 10.7 cm Flux
  Observed       21 Dec 234
  Predicted   22 Dec-24 Dec  240/240/240
  90 Day Mean        21 Dec 218
V. Geomagnetic A Indices
  Observed Afr/Ap 20 Dec  002/005
  Estimated     Afr/Ap 21 Dec  010/010
  Predicted    Afr/Ap 22 Dec-24 Dec  012/010-010/010-008/012
VI. Geomagnetic Activity Probabilities 22 Dec to 24 Dec
A. Middle Latitudes
Minor storm10%10%05%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm15%15%15%
Major-severe storm05%05%05%

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