Viewing archive of Friday, 21 April 2006
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 2006 Apr 21 2204 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 111 Issued at 2200Z on 21 Apr 2006IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z Solar activity continued very low. Region 874
(S01W25), the sole spotted region visible, was stable and quiet.
There are signs of new flux emerging in the southeast, where two
small groups are in the formative stage. The limbs were quiet.
IB. Solar Activity Forecast
Solar activity is expected to be very
low to low.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
The geomagnetic field was quiet to active. A period of enhanced solar
wind conditions began around midday, when Alfven waves caused Bz to
reach -10 nT for a brief period. Those fluctuations are still
occurring. The greater than 2 MeV electron flux at GOES was again at
high levels.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be predominantly quiet to unsettled for the next three
days. Solar wind wave activity may persist for the next few hours,
and there is a chance of another short-lived disturbance from
high-speed solar wind on April 23.
III. Event Probabilities 22 Apr to 24 Apr
| Class M | 05% | 05% | 05% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 21 Apr 079 Predicted 22 Apr-24 Apr 080/080/085 90 Day Mean 21 Apr 078
V. Geomagnetic A Indices
Observed Afr/Ap 20 Apr 003/005 Estimated Afr/Ap 21 Apr 006/008 Predicted Afr/Ap 22 Apr-24 Apr 005/008-010/010-005/008
VI. Geomagnetic Activity Probabilities 22 Apr to 24 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 15% | 20% | 15% |
| Minor storm | 01% | 05% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 20% | 20% | 20% |
| Minor storm | 05% | 10% | 05% |
| Major-severe storm | 01% | 01% | 01% |
All times in UTC
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