Viewing archive of Sunday, 11 August 2002

Solar activity report

Report of Solar-Geophysical Activity 2002 Aug 11 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 223 Issued at 2200Z on 11 Aug 2002

IA. Analysis of Solar Active Regions and Activity from 10-2100Z to 11-2100Z

Solar activity remained at low levels. The two largest x-ray flares of the period were optically uncorrelated: A C9.5 flare at 11/1147 UTC, and a C7.9 flare at 11/1801 UTC. LASCO imagery revealed no evident CME activity following the first event, and was unavailable for the second event, however neither event was accompanied by any significant CME-related radio emissions. A 19-degree filament disappearance occurred near N28W51 at about 11/0700, close to the western end of a long filament channel that extends to the northeast limb. No CME was evident in available LASCO imagery following this event. Regions 61 (N07W28), 66 (N13E42), and newly numbered 69 (S08E77) were all sources of lesser C-class activity. Region 61 appears to be undergoing an accelerated decay in size and complexity. New Region 69 appears large and complex in white light, but its limb proximity prevents a detailed magnetic analysis. Three other regions were also numbered: 70 (N05W05), 71 (N11E68), and 72 (N18W23). All appear relatively simply structured at present. 10cm flux experienced a rapid rise with the appearance of the new regions.
IB. Solar Activity Forecast
Solar activity is expected to be predominantly low, but with a fair chance for isolated M-class activity over the next three days, primarily due to new Region 69.
IIA. Geophysical Activity Summary 10-2100Z to 11-2100Z
The geomagnetic field was quiet to active. A trend toward elevated solar wind speed and sustained southward Bz appeared to persist for most of the day, and may indicate the early influence of expected high speed stream effects.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to range from quiet to active conditions for the next three days.
III. Event Probabilities 12 Aug to 14 Aug
Class M 35%35%35%
Class X 01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       11 Aug 172
  Predicted    12 Aug-14 Aug  175/180/185
  90 Day Mean        11 Aug 164
V. Geomagnetic A Indices
  Observed Afr/Ap 10 Aug  013/016
  Estimated     Afr/Ap 11 Aug  013/018
  Predicted     Afr/Ap 12 Aug-14 Aug  012/012-015/015-012/012
VI. Geomagnetic Activity Probabilities 12 Aug to 14 Aug
A. Middle Latitudes
Minor storm 10%10%10%
Major-severe storm 01%01%01%
B. High Latitudes
Minor storm 10%10%10%
Major-severe storm 01%01%01%

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