Viewing archive of Tuesday, 21 September 1999
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 1999 Sep 21 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 264 Issued at 2200Z on 21 SEP 1999IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z SOLAR ACTIVITY WAS LOW. A C9/SF FLARE FROM REGION 8706
(N22E54) WAS THE HIGHLIGHT OF THE DAY. JUST PRIOR TO THAT, A C5
X-RAY EVENT WAS ASSOCIATED WITH AN ERUPTIVE PROMINENCE FROM REGION
8699 (N19W90). A WEAK TYPE II SWEEP OCCURRED IN CONJUNCTION WITH THE
ERUPTION. ALL DISK REGIONS WERE EITHER STABLE OR DECLINING DURING
THE INTERVAL.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO REMAIN
LOW THROUGHOUT THE PERIOD.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. THE GREATER THAN 2 MEV
ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT REACHED HIGH LEVELS MIDWAY
THROUGH THE DAY.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE UNSETTLED THE NEXT THREE DAYS.
III. Event Probabilities 22 SEP to 24 SEP
| Class M | 10% | 10% | 10% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 21 SEP 147 Predicted 22 SEP-24 SEP 145/145/140 90 Day Mean 21 SEP 164
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 SEP 006/010 ESTIMATED AFR/AP 21 SEP 007/010 PREDICTED AFR/AP 22 SEP-24 SEP 010/008-010/010-010/012
VI. Geomagnetic Activity Probabilities 22 SEP to 24 SEP
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 20% | 20% | 20% |
| Minor storm | 05% | 05% | 05% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 25% | 25% | 25% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 01% | 01% | 01% |
All times in UTC
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