Viewing archive of Saturday, 27 April 2002

Solar activity report

Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.
Report of Solar-Geophysical Activity 2002 Apr 27 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 117 Issued at 2200Z on 27 Apr 2002

IA. Analysis of Solar Active Regions and Activity from 26-2100Z to 27-2100Z

Solar activity was low. The largest event of the period was a C4/Sf from Region 9919 (N12E14). Other minor C-class flares were observed in this Beta region. No significant activity or changes were noted in the remaining active regions. The filament eruption observed late in the last period from near S32W12 produced a large CME, but it does not appear Earthbound. New Region 9926 (N12E26) was numbered today. This spot cluster was formerly grouped with Region 9919, but magnetograms indicate that it is a separate region.
IB. Solar Activity Forecast
Solar activity is expected to continue at low levels. Regions 9915 (N11W26) and 9919 will likely produce C-class flares.
IIA. Geophysical Activity Summary 26-2100Z to 27-2100Z
The geomagnetic field was mostly quiet, but became unsettled late in the period. Solar wind indices on ACE suggest that we are transitioning into a high speed coronal hole stream. The greater than 10 MeV protons at geosynchronous orbit remain elevated following the proton event that began on 21 Apr and ended on the 26th.
IIB. Geophysical Activity Forecast
The geomagnetic field is expected to be mostly unsettled with isolated active periods at all latitudes due to high speed coronal hole flow. Minor storm conditions are expected at high latitudes during local nighttime hours. Expect quiet to unsettled conditions to return by day three.
III. Event Probabilities 28 Apr to 30 Apr
Class M25%25%25%
Class X05%05%05%
Proton01%01%01%
PCAFgreen
IV. Penticton 10.7 cm Flux
  Observed       27 Apr 157
  Predicted   28 Apr-30 Apr  160/160/165
  90 Day Mean        27 Apr 195
V. Geomagnetic A Indices
  Observed Afr/Ap 26 Apr  002/006
  Estimated     Afr/Ap 27 Apr  007/010
  Predicted    Afr/Ap 28 Apr-30 Apr  012/012-010/010-008/008
VI. Geomagnetic Activity Probabilities 28 Apr to 30 Apr
A. Middle Latitudes
Active35%35%30%
Minor storm15%15%10%
Major-severe storm05%05%01%
B. High Latitudes
Active45%45%35%
Minor storm25%25%15%
Major-severe storm10%10%05%

All times in UTC

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