Viewing archive of Sunday, 20 September 1998
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 1998 Sep 20 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 263 Issued at 2200Z on 20 SEP 1998IA. Analysis of Solar Active Regions and Activity from 19-2100Z to 20-2100Z SOLAR ACTIVITY WAS MODERATE. REGION 8340 (N19E38)
PRODUCED AN M1 FLARE AT 19/0251Z. A STRONG TYPE IV SWEEP AND 340 SFU
TENFLARE ACCOMPANIED THIS FLARE. REGION 8336 (S29W02) PRODUCED A
C1/SF AT 19/0949Z AND IS SHOWING SIGNS OF FURTHER DEVELOPMENT.
REGION 8342 (N18E25) WAS ACTIVE THROUGHOUT THE PERIOD EXHIBITING
FREQUENT PLAGE FLUCTUATIONS WHILE PRODUCING SEVERAL SUBFLARES.
REMAINING REGIONS WERE QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE
PREDOMINANTLY LOW. REGIONS 8336 AND 8340 ARE BOTH CAPABLE OF
PRODUCING C-CLASS ACTIVITY AND HAVE AN OUTSIDE CHANCE OF AN M-CLASS
FLARE. REGION 8342 IS STILL DEVELOPING AND MAY SOON BE CAPABLE OF
C-CLASS ACTIVITY.
IIA. Geophysical Activity Summary 19-2100Z to 20-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED WITH OCCASIONAL ACTIVE PERIODS AT
MOSTLY HIGH LATITUDES.
III. Event Probabilities 21 SEP to 23 SEP
| Class M | 10% | 10% | 10% |
| Class X | 01% | 01% | 01% |
| Proton | 01% | 01% | 01% |
| PCAF | GREEN | ||
IV. Penticton 10.7 cm Flux
Observed 20 SEP 132 Predicted 21 SEP-23 SEP 135/135/140 90 Day Mean 20 SEP 128
V. Geomagnetic A Indices
OBSERVED AFR/AP 19 SEP 008/012 ESTIMATED AFR/AP 20 SEP 009/010 PREDICTED AFR/AP 21 SEP-23 SEP 015/015-015/015-015/015
VI. Geomagnetic Activity Probabilities 21 SEP to 23 SEP
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 30% | 30% |
| Minor storm | 10% | 10% | 10% |
| Major-severe storm | 01% | 01% | 01% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 40% | 40% | 40% |
| Minor storm | 15% | 15% | 15% |
| Major-severe storm | 05% | 05% | 05% |
All times in UTC
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