Viewing archive of Friday, 18 April 2003

Solar activity report

Report of Solar-Geophysical Activity 2003 Apr 18 2200 UTC
Prepared by the NOAA © SWPC and processed by

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 108 Issued at 2200Z on 18 Apr 2003

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

Solar activity has been at moderate levels. There were several minor C-class events during the last 24 hours with a single M1.1 from Region 337 (S12E74) at 1958 UTC. A 13 degree disappearing solar filament was observed early in the period near Region 335 (S25E21). There was a small coronal mass ejection associated with that filament, but it was not earth-directed.
IB. Solar Activity Forecast
Solar activity is expected to be at low to moderate levels for the entire period. Region 337 (S12E74) is just coming on to the visible disk, and appears in solar x-ray imagery to be a potentially active region.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was at unsettled to active levels with an isolated quiet period from 0300 UTC to 0600 UTC. The coronal hole induced high speed solar wind stream continues. The greater than 2 MeV electron fluxes at geo-synchronous orbit reached high levels today.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be at mostly unsettled levels as the current disturbance continues to transition out of geoeffective range. Continued unsettled levels are expected through day two, with a further decrease to mostly quiet levels on day three.
III. Event Probabilities 19 Apr to 21 Apr
Class M05%05%05%
Class X01%01%01%
IV. Penticton 10.7 cm Flux
  Observed       18 Apr 108
  Predicted   19 Apr-21 Apr  110/110/115
  90 Day Mean        18 Apr 127
V. Geomagnetic A Indices
  Observed Afr/Ap 17 Apr  020/030
  Estimated     Afr/Ap 18 Apr  018/019
  Predicted    Afr/Ap 19 Apr-21 Apr  012/015-010/012-007/010
VI. Geomagnetic Activity Probabilities 19 Apr to 21 Apr
A. Middle Latitudes
Minor storm25%15%15%
Major-severe storm05%05%05%
B. High Latitudes
Minor storm30%25%20%
Major-severe storm20%10%10%

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