Viewing archive of Friday, 20 September 2002

Solar activity report

Report of Solar-Geophysical Activity 2002 Sep 20 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 263 Issued at 2200Z on 20 Sep 2002

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

Solar activity was moderate. New Region 126 (S24E62) produced two M-class flares this period. Both were M1/Sf flares, at 20/0512Z and 0928Z, and both were accompanied by minor centimetric bursts. Limb proximity makes it too difficult to accurately assess Region 126's complexity, but initial measurements indicate a D type group with 200 millionths of white light areal coverage. Region 119 (S14W24) continues to grow and the delta configuration is now more pronounced. Despite this region's moderate complexity, flare output has been nothing more than occasional minor C-class flares. Early in the period, a large CME was observed, originating along a filament channel near S30E12. The ejecta does not appear earthward directed. New Regions 127 (S14E19) and 128 (N11E63) were numbered today. Region 127 is in close proximity to Region 122 (S18E21), but the consensus is that these are separate regions.
IB. Solar Activity Forecast
Solar activity is expected to continue at low to moderate levels. Low M-class flares are possible from Regions 119 and 126.
IIA. Geophysical Activity Summary 19-2100Z to 20-2100Z
The geomagnetic field was quiet to unsettled. Solar wind speed began the period near 700 km/s following the arrival of a CME earlier yesterday. However, a weak IMF with sustained northward Bz offset any significant impact on the geomagnetic field.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to remain at quiet to unsettled levels for the next three days.
III. Event Probabilities 21 Sep to 23 Sep
Class M50%50%50%
Class X05%05%05%
IV. Penticton 10.7 cm Flux
  Observed       20 Sep 164
  Predicted   21 Sep-23 Sep  165/160/160
  90 Day Mean        20 Sep 178
V. Geomagnetic A Indices
  Observed Afr/Ap 19 Sep  011/013
  Estimated     Afr/Ap 20 Sep  006/010
  Predicted    Afr/Ap 21 Sep-23 Sep  008/012-008/010-008/010
VI. Geomagnetic Activity Probabilities 21 Sep to 23 Sep
A. Middle Latitudes
Minor storm05%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm05%05%05%
Major-severe storm01%01%01%

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