Viewing archive of Wednesday, 12 September 2001

Solar activity report

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

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 255 Issued at 2200Z on 12 Sep 2001

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

Solar activity was moderate. A M1 class flare occurred at 12/0444 UT. SOHO/EIT imagery suggests this flare originated from Region 9608 (S26W18). Regions 9608 (S26W18) and 9610 (S13W05) have become more compact and increased in sunspot number. Numerous C-class flares also occurred. New data from SOHO/LASCO, together with H-alpha imagery, revealed a disappearing filament and associated halo CME which occurred on September 11 near spotless Region 9615 (N11E23). This event was also accompanied with a modest long duration optical and x-ray enhancements during 11/1416-1530 UT. New Region 9617 (N10E71) was numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be moderate to high. Regions 9608 (S26W18), 9610 (S13E05), and 9616 (S11E69) are all potential sources of significant flares. Region 9608 is the most complex and capable of a major flare.
IIA. Geophysical Activity Summary 11-2100Z to 12-2100Z
Geomagnetic activity was at quiet to active levels. High speed stream effects appear to be diminishing.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to range from quiet to active with isolated minor storm conditions possible through days one and two, in response to the disappearing filament activity noted in section 1A above, along with the remaining possibility of some effect from the CME activity of September 9. By day three, predominantly quiet to unsettled conditions are expected.
III. Event Probabilities 13 Sep to 15 Sep
Class M80%80%80%
Class X15%15%15%
IV. Penticton 10.7 cm Flux
  Observed       12 Sep 235
  Predicted   13 Sep-15 Sep  235/235/225
  90 Day Mean        12 Sep 164
V. Geomagnetic A Indices
  Observed Afr/Ap 11 Sep  012/009
  Estimated     Afr/Ap 12 Sep  014/015
  Predicted    Afr/Ap 13 Sep-15 Sep  015/015-018/020-012/012
VI. Geomagnetic Activity Probabilities 13 Sep to 15 Sep
A. Middle Latitudes
Minor storm15%15%10%
Major-severe storm05%05%01%
B. High Latitudes
Minor storm15%20%10%
Major-severe storm05%05%05%

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