Viewing archive of Wednesday, 12 December 2001

Solar activity report

Report of Solar-Geophysical Activity 2001 Dec 12 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 346 Issued at 2200Z on 12 Dec 2001

IA. Analysis of Solar Active Regions and Activity from 11-2100Z to 12-2100Z

Solar activity decreased to moderate levels. Region 9733 (N14E18) produced an M3/1n flare at 12/1911 UTC associated with a 420 sfu Tenflare. This large, complex spot group remained in a growth phase with a delta magnetic configuration observed within its northernmost trailer spots. Region 9727 (S21W52) produced occasional subflares, the largest of which was a C9 at 12/2024 UTC. This region also grew during the period and remained large and complex with delta magnetic configurations in its interior and trailer spots. Region 9736 (S09W55) showed minor growth during the period and produced isolated C-class subflares. New Region 9738 (S21E67) was numbered.
IB. Solar Activity Forecast
Solar activity is expected to be at moderate to high levels with isolated, low-level M-class flares likely. There will also be a chance for a major flare from Regions 9727 or 9733.
IIA. Geophysical Activity Summary 11-2100Z to 12-2100Z
Geomagnetic field activity ranged from quiet to minor storm levels. Unsettled to minor storm levels occurred during 12/0900 - 1200 UTC. ACE data suggest a solar sector boundary crossing (positive- to negative-polarity) as the cause for this brief period of increased activity. Mostly quiet levels occurred during the remainder of the period.
IIB. Geophysical Activity Forecast
Geomagnetic field activity is expected to be at quiet to unsettled levels during most of the period. However, brief active periods will be possible during 14 - 15 December due to coronal hole effects. There will be a chance for a proton flare from Regions 9727 or 9733.
III. Event Probabilities 13 Dec to 15 Dec
Class M80%80%80%
Class X20%20%20%
IV. Penticton 10.7 cm Flux
  Observed       12 Dec 237
  Predicted   13 Dec-15 Dec  220/220/210
  90 Day Mean        12 Dec 219
V. Geomagnetic A Indices
  Observed Afr/Ap 11 Dec  003/004
  Estimated     Afr/Ap 12 Dec  012/012
  Predicted    Afr/Ap 13 Dec-15 Dec  012/012-012/015-012/015
VI. Geomagnetic Activity Probabilities 13 Dec to 15 Dec
A. Middle Latitudes
Minor storm10%10%10%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm15%15%15%
Major-severe storm05%05%01%

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