Viewing archive of Sunday, 19 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 19 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 19 SEP 1999IA. Analysis of Solar Active Regions and Activity from 18-2100Z to 19-2100Z SOLAR ACTIVITY WAS LOW. REGIONS 8699 (N23W78) AND 8700
(N12W05) CONTINUED TO PRODUCE C-CLASS SUBFLARES. THE LARGEST FLARE
OF THE PAST DAY WAS A C4/SF AT 19/1440UT IN REGION 8699. NEITHER
REGION APPEARS SIGNIFICANTLY COMPLEX. NEW REGION 8706 (N19E77)
APPEARS TO BE RETURNING REGION 8681 WHICH LEFT THE DISK LAST
ROTATION AS A DECAYING SUNSPOT GROUP.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. C-CLASS FLARES ARE LIKELY IN REGIONS 8699 AND 8700.
REGION 8700 IS THE BEST CANDIDATE FOR AN ISOLATED M-CLASS FLARE.
IIA. Geophysical Activity Summary 18-2100Z to 19-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. THE GREATER THAN 2 MEV
ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT WAS HIGH.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO REACH ACTIVE TO STORM LEVELS BY THE END OF SEP 20 DUE TO
A CME/DSF OBSERVED ON SEP 16. THE FIELD SHOULD RETURN TO QUIET TO
UNSETTLED CONDITIONS BY THE END OF THE THREE-DAY FORECAST PERIOD.
III. Event Probabilities 20 SEP to 22 SEP
| Class M | 15% | 15% | 15% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 19 SEP 149 Predicted 20 SEP-22 SEP 146/144/142 90 Day Mean 19 SEP 164
V. Geomagnetic A Indices
OBSERVED AFR/AP 18 SEP 013/016 ESTIMATED AFR/AP 19 SEP 015/015 PREDICTED AFR/AP 20 SEP-22 SEP 030/030-015/015-010/012
VI. Geomagnetic Activity Probabilities 20 SEP to 22 SEP
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 50% | 30% | 20% |
| Minor storm | 30% | 10% | 05% |
| Major-severe storm | 10% | 05% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 50% | 30% | 20% |
| Minor storm | 30% | 10% | 05% |
| Major-severe storm | 10% | 05% | 01% |
All times in UTC
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