Viewing archive of Wednesday, 23 September 1998

Solar activity report

Report of Solar-Geophysical Activity 1998 Sep 23 2200 UTC
Prepared 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 1998

IA. 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 FROM 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 M30%30%25%
Class X05%05%01%
Proton05%05%01%
PCAFYELLOW
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
Active30%50%30%
Minor storm15%30%15%
Major-severe storm05%10%05%
B. High Latitudes
Active50%65%50%
Minor storm10%30%10%
Major-severe storm01%05%01%

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