Viewing archive of Sunday, 18 April 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 Apr 18 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 109 Issued at 2200Z on 18 Apr 2004IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z Solar activity was very low. Occasional B-class flares
were observed in newly numbered Region 596 (S08E60). This developing
D-type group exhibited frequent brightness fluctuations throughout
the period. New spots have reemerged in Region 593 (S18W11). No
significant changes were observed in the remaining small active
regions.
IB. Solar Activity Forecast
Solar activity is expected to be low.
Isolated C-class events are likely from Region 596.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
The geomagnetic field was quiet to unsettled with an isolated active
period between 18/0600 - 0900Z. Solar wind speed ranged from 350 to
400 km/s.
IIB. Geophysical Activity Forecast
The geomagnetic field is
expected to be quiet to unsettled.
III. Event Probabilities 19 Apr to 21 Apr
| Class M | 10% | 10% | 10% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | green | ||
IV. Penticton 10.7 cm Flux
Observed 18 Apr 109 Predicted 19 Apr-21 Apr 115/115/120 90 Day Mean 18 Apr 107
V. Geomagnetic A Indices
Observed Afr/Ap 17 Apr 006/009 Estimated Afr/Ap 18 Apr 008/008 Predicted Afr/Ap 19 Apr-21 Apr 005/008-005/008-005/008
VI. Geomagnetic Activity Probabilities 19 Apr to 21 Apr
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 10% | 10% | 10% |
| Minor storm | 01% | 01% | 01% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 15% | 15% | 15% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
All times in UTC
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