Viewing archive of Saturday, 18 September 2004
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 2004 Sep 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 262 Issued at 2200Z on 18 Sep 2004IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity was low. Region 673 (S13E35) produced
the only C-class activity of the period, a single C1 flare at
18/1609Z. Occasional B-class flares were also observed from this
region and from Region 672 (N06W45). Region 673 is a moderate size
beta group that exhibited little change this period. Region 672 has
decayed considerably over the past 48 hours. No other significant
activity or changes were noted.
IB. Solar Activity Forecast
Solar activity is expected to be low
to very low. Isolated C-class activity is possible from Regions 672
and 673.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field ranged from quiet to minor storm levels with a
period of major storming between 18/0000 - 0300Z. The storm levels
were in response to a prolonged period of southward IMF Bz and solar
wind speeds near 500 km/s. The geomagnetic field was predominantly
quiet to end the period as the solar wind speed declined to 420 km/s
and IMF Bz was sustained north. The greater than 2 MeV electron flux
at geosynchronous orbit was at high levels.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be quiet to unsettled with isolated active periods at
high latitudes.
III. Event Probabilities 19 Sep to 21 Sep
| Class M | 05% | 05% | 05% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Sep 103 Predicted 19 Sep-21 Sep 100/095/095 90 Day Mean 18 Sep 112
V. Geomagnetic A Indices
Observed Afr/Ap 17 Sep 015/020 Estimated Afr/Ap 18 Sep 015/015 Predicted Afr/Ap 19 Sep-21 Sep 010/012-008/010-005/010
VI. Geomagnetic Activity Probabilities 19 Sep to 21 Sep
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 25% | 20% | 15% |
| Minor storm | 10% | 05% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 25% | 20% |
| Minor storm | 15% | 10% | 10% |
| Major-severe storm | 05% | 05% | 05% |
All times in UTC
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