Viewing archive of Tuesday, 17 April 2001
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 2001 Apr 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 107 Issued at 2200Z on 17 Apr 2001IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z Solar activity has been low. There were several
optically uncorrelated C-class events during the period. New Region
9431 (S10E49) was numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be low
with an isolated chance for a M-class event.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic field was quiet to unsettled. The greater than 10
MeV proton event that started on April 15 is still in progress. The
greater than 100 proton event that began at 15/1405 UTC reached a
maximum of 146 pfu at 15/1525 UTC and ended at 17/0515 UTC. The
polar cap absorption (PCA) event ended at 17/0315 UTC. The greater
than 2 MeV electrons at geosynchronous orbit remained at high levels
and above threshold through the period.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be unsettled to active for April 18 and 19 as a result
of possible effects from the X14/2b event on April 15, and possible
effects from a well positioned coronal hole. Quiet to unsettled
conditions are expected to return on April 20. The greater than 10
MeV proton event is expected to go below threshold on April 18.
III. Event Probabilities 18 Apr to 20 Apr
| Class M | 60% | 50% | 50% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 17 Apr 126 Predicted 18 Apr-20 Apr 135/145/155 90 Day Mean 17 Apr 165
V. Geomagnetic A Indices
Observed Afr/Ap 16 Apr 007/007 Estimated Afr/Ap 17 Apr 008/015 Predicted Afr/Ap 18 Apr-20 Apr 020/025-015/020-010/015
VI. Geomagnetic Activity Probabilities 18 Apr to 20 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 50% | 25% | 20% |
| Minor storm | 10% | 05% | 05% |
| Major-severe storm | 05% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 50% | 40% | 30% |
| Minor storm | 15% | 10% | 10% |
| Major-severe storm | 10% | 05% | 05% |
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