Viewing archive of Saturday, 18 August 2001

Solar activity report

Report of Solar-Geophysical Activity 2001 Aug 18 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 230 Issued at 2200Z on 18 Aug 2001

IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z

Solar activity was low. Several C-class flares occurred, principally from Region 9582 (N28E33). The other main area of note is Region 9585 (N15E50) which has grown considerably in sunspot area and has increased its magnetic complexity.
IB. Solar Activity Forecast
Solar activity is expected to be low. Additional C-class flares are possible in Regions 9582 and 9585. A small chance of M-level activity also exists.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field remained at storm levels until about 18/0000 UTC and was mostly unsettled to active after that. The greater than 10 MeV solar energetic proton event continues to slowly decay and has been fluctuating around the 10 pfu event threshold for most of the day.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be unsettled to active becoming quiet to unsettled by the second day of the forecast period. The greater than 10 MeV proton event is expected to end by 19 August.
III. Event Probabilities 19 Aug to 21 Aug
Class M10%10%10%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       18 Aug 156
  Predicted   19 Aug-21 Aug  160/165/170
  90 Day Mean        18 Aug 151
V. Geomagnetic A Indices
  Observed Afr/Ap 17 Aug  027/029
  Estimated     Afr/Ap 18 Aug  015/015
  Predicted    Afr/Ap 19 Aug-21 Aug  012/012-010/015-010/012
VI. Geomagnetic Activity Probabilities 19 Aug to 21 Aug
A. Middle Latitudes
Minor storm05%01%01%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm05%05%05%
Major-severe storm01%01%01%

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