Viewing archive of Friday, 27 April 2007
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 2007 Apr 27 2203 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 2007IA. Analysis of Solar Active Regions and Activity from 26-2100Z to 27-2100Z Solar activity was very low during the past 24 hours.
Region 953 (S10E49) produced several B-class events during the past
24 hours. As the region has rotated more fully into view, it now
appears that the group consists mostly of a large penumbral area
which contains opposite magnetic polarities, making the group a
beta-delta magnetic classification.
IB. Solar Activity Forecast
Solar activity is expected to be very
low to low for the next three days (28-30 April), with a slight
chance for an isolated M-class event from Region 953.
IIA. Geophysical Activity Summary 26-2100Z to 27-2100Z
The geomagnetic field was quiet to active during the past 24 hours.
An initially quiet to unsettled field became unsettled to active
with the onset of a high speed solar wind stream around 1500Z. Solar
wind velocity increased to about 600 km/s and the interplanetary
magnetic field showed fluctuations from about -9 nT to +7 nT.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be mostly active with a chance for isolated minor storm
periods for the next 24 hours (28 April) as the high speed stream is
expected to continue. Unsettled levels with a chance for active
periods is expected for the second day (29 April) and conditions
should decline to mostly unsettled by the third day (30 April).
III. Event Probabilities 28 Apr to 30 Apr
| Class M | 15% | 15% | 15% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | Green | ||
IV. Penticton 10.7 cm Flux
Observed 27 Apr 083 Predicted 28 Apr-30 Apr 085/085/085 90 Day Mean 27 Apr 074
V. Geomagnetic A Indices
Observed Afr/Ap 26 Apr 004/006 Estimated Afr/Ap 27 Apr 008/012 Predicted Afr/Ap 28 Apr-30 Apr 020/030-015/015-010/010
VI. Geomagnetic Activity Probabilities 28 Apr to 30 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 45% | 30% | 15% |
| Minor storm | 25% | 15% | 05% |
| Major-severe storm | 10% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 45% | 30% | 20% |
| Minor storm | 30% | 20% | 15% |
| Major-severe storm | 15% | 10% | 05% |
All times in UTC
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