Viewing archive of Sunday, 18 April 2004

Solar activity report

Report of Solar-Geophysical Activity 2004 Apr 18 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 109 Issued at 2200Z on 18 Apr 2004

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

Solar activity was very low. Occasional B-class flares were observed in newly numbered Region 596 (S08E60). This developing D-type group exhibited frequent brightness fluctuations throughout the period. New spots have reemerged in Region 593 (S18W11). No significant changes were observed in the remaining small active regions.
IB. Solar Activity Forecast
Solar activity is expected to be low. Isolated C-class events are likely from Region 596.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was quiet to unsettled with an isolated active period between 18/0600 - 0900Z. Solar wind speed ranged from 350 to 400 km/s.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be quiet to unsettled.
III. Event Probabilities 19 Apr to 21 Apr
Class M10%10%10%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       18 Apr 109
  Predicted   19 Apr-21 Apr  115/115/120
  90 Day Mean        18 Apr 107
V. Geomagnetic A Indices
  Observed Afr/Ap 17 Apr  006/009
  Estimated     Afr/Ap 18 Apr  008/008
  Predicted    Afr/Ap 19 Apr-21 Apr  005/008-005/008-005/008
VI. Geomagnetic Activity Probabilities 19 Apr to 21 Apr
A. Middle Latitudes
Minor storm01%01%01%
Major-severe storm01%01%01%
B. High Latitudes
Minor storm05%05%05%
Major-severe storm01%01%01%

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