Viewing archive of Tuesday, 18 December 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 Dec 18 2203 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 352 Issued at 2200Z on 18 Dec 2007IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity was at low levels. Region 978 (S08W91)
has produced several C-class events, the largest being a C2 at
18/1320Z.
IB. Solar Activity Forecast
Solar activity is expected to be at
very low to low levels. Activity levels should decrease with the
rotation of Region 978 beyond the west limb.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was at predominately unsettled to active
levels. This elevated activity is due to a coronal hole high speed
stream that has rotated into a geoeffective position. Measurements
at the ACE spacecraft indicated a steady increase in solar wind
speed. At the time of forecast issue the wind speed was
approximately 700 km/s.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be at mostly unsettled to active levels for 19 to 21
December due to the continued influence of the high speed stream.
III. Event Probabilities 19 Dec to 21 Dec
| Class M | 05% | 01% | 01% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | Green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Dec 077 Predicted 19 Dec-21 Dec 070/070/070 90 Day Mean 18 Dec 071
V. Geomagnetic A Indices
Observed Afr/Ap 17 Dec 012/017 Estimated Afr/Ap 18 Dec 015/020 Predicted Afr/Ap 19 Dec-21 Dec 015/015-015/015-012/012
VI. Geomagnetic Activity Probabilities 19 Dec to 21 Dec
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 50% | 50% | 40% |
| Minor storm | 20% | 20% | 15% |
| Major-severe storm | 05% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 50% | 50% | 40% |
| Minor storm | 25% | 25% | 20% |
| Major-severe storm | 10% | 10% | 05% |
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