Viewing archive of Wednesday, 23 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 23 2200 UTCPrepared by the NOAA © SWPC and processed by SpaceWeatherLive.com
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 266 Issued at 2200Z on 23 SEP 1998IA. Analysis of Solar Active Regions and Activity from 22-2100Z to 23-2100Z SOLAR ACTIVITY WAS HIGH DUE TO AN M6.9/3B FLARE THAT
OCCURRED IN REGION 8340 (N20W02) AT 23/0713UT. THIS WAS A LONG
DURATION EVENT THAT ALSO PRODUCED A TYPE II AND A TYPE IV SWEEP.
THERE IS A FAIR POSSIBILITY THAT A PROTON EVENT WAS ALSO GENERATED
DURING THIS ACTIVITY. REGION 8340 ALSO PRODUCED A C2 X-RAY FLARE AND
3 OPTICAL SUBFLARES DURING THE PERIOD. OTHER ACTIVE REGIONS WERE
8344 (S20E09) WHICH PRODUCED A C9/SF AT 23/0038UT AND REGION 8343
(N38E13) WHICH PRODUCED A SINGLE OPTICAL SUB FLARE DURING THE
PERIOD. THE REST OF THE REGIONS WERE STABLE AND MOSTLY QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW
TO MODERATE. REGION 8340 CAN BE EXPECTED TO PRODUCE CONTINUED
C-CLASS FLARES AND A POSSIBLE M-CLASS EVENT.
IIA. Geophysical Activity Summary 22-2100Z to 23-2100Z
GEOMAGNETIC ACTIVITY WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS
EXPECTED TO BE QUIET TO UNSETTLED WITH POSSIBLE ACTIVE PERIODS AT
HIGH LATITUDES. THERE IS A FAIR CHANCE OF A PROTON EVENT RESULTING
FROM THE M6 FLARE AND THE ASSOCIATED TYPE II AND IV SWEEPS THAT
OCCURRED ON 23/0713. PROJECTED ARRIVAL OF THE PROTON EVENT IS EARLY
ON 24 SEPT AT AROUND 0300UT.
III. Event Probabilities 24 SEP to 26 SEP
| Class M | 30% | 30% | 25% |
| Class X | 05% | 05% | 01% |
| Proton | 05% | 05% | 01% |
| PCAF | YELLOW | ||
IV. Penticton 10.7 cm Flux
Observed 23 SEP 143 Predicted 24 SEP-26 SEP 150/150/155 90 Day Mean 23 SEP 129
V. Geomagnetic A Indices
OBSERVED AFR/AP 22 SEP 006/010 ESTIMATED AFR/AP 23 SEP 012/012 PREDICTED AFR/AP 24 SEP-26 SEP 020/020-040/040-020/020
VI. Geomagnetic Activity Probabilities 24 SEP to 26 SEP
| A. Middle Latitudes | |||
|---|---|---|---|
| Active | 30% | 50% | 30% |
| Minor storm | 15% | 30% | 15% |
| Major-severe storm | 05% | 10% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 50% | 65% | 50% |
| Minor storm | 10% | 30% | 10% |
| Major-severe storm | 01% | 05% | 01% |
All times in UTC
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