Viewing archive of Tuesday, 21 September 1999

Solar activity report

Report of Solar-Geophysical Activity 1999 Sep 21 2200 UTC
Prepared 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 1999

IA. 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 FROM 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 M10%10%10%
Class X01%01%01%
Proton01%01%01%
PCAFGREEN
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
Active20%20%20%
Minor storm05%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Active25%25%25%
Minor storm10%10%10%
Major-severe storm01%01%01%

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