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 UTCPrepared 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 2002IA. 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 M | 25% | 25% | 25% |
| Class X | 05% | 05% | 05% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
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 | |||
|---|---|---|---|
| Active | 35% | 35% | 30% |
| Minor storm | 15% | 15% | 10% |
| Major-severe storm | 05% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 45% | 45% | 35% |
| Minor storm | 25% | 25% | 15% |
| Major-severe storm | 10% | 10% | 05% |
All times in UTC
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