Viewing archive of Friday, 17 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 17 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 261 Issued at 2200Z on 17 Sep 2004IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z Solar activity has been very low. X-ray flux has
remained at background levels. Surging was observed from Region 673
(S13E51), and the region grew slightly over the period to 320
millionths in white light. No new regions were numbered today.
IB. Solar Activity Forecast
Solar activity is expected to be very
low to low. Regions 672 (N05W29) and 673 are capable of C-class
flares.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
The geomagnetic field was at quiet to minor storm levels, most likely
caused by the increased solar wind from a geoeffective coronal hole.
Solar wind speed at ACE began to diminsh around 0900 UTC and was at
approximately 450 km/s at the end of the period. The greater than 2
MeV electron flux at geosynchronous orbit reached high levels today.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be quiet to unsettled.
III. Event Probabilities 18 Sep to 20 Sep
| Class M | 20% | 20% | 20% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 17 Sep 105 Predicted 18 Sep-20 Sep 105/105/100 90 Day Mean 17 Sep 111
V. Geomagnetic A Indices
Observed Afr/Ap 16 Sep 014/017 Estimated Afr/Ap 17 Sep 015/020 Predicted Afr/Ap 18 Sep-20 Sep 010/015-010/012-008/012
VI. Geomagnetic Activity Probabilities 18 Sep to 20 Sep
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 30% | 30% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 40% | 35% | 30% |
| Minor storm | 25% | 25% | 20% |
| Major-severe storm | 15% | 10% | 10% |
All times in UTC
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