Viewing archive of Monday, 20 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 20 2200 UTC
Prepared 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 1999

IA. Analysis of Solar Active Regions and Activity from 19-2100Z to 20-2100Z

SOLAR ACTIVITY WAS LOW. REGION 8699 (N24W88) PRODUCED THE LARGEST FLARE, A C9/1F AT 19/2312UT. REGION 8700 (N12W19) ALSO PRODUCED SMALL C-CLASS FLARES. REGION 8700 CONTINUES TO SLOWLY DECAY. REMAINING DISK REGIONS ARE SMALL AND SIMPLE.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW TO MODERATE. C-CLASS ACTIVITY IS EXPECTED TO CONTINUE, PRIMARILY IN REGION 8700. THE LIKELIHOOD OF M-CLASS ACTIVITY IS DIMINISHING WITH THE DEPARTURE OF REGION 8699 AND THE DECAY IN REGION 8700.
IIA. Geophysical Activity Summary 19-2100Z to 20-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. THE GREATER THAN 2 MEV ELECTRON FLUX WAS MODERATE TO HIGH.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE QUIET TO UNSETTLED. A SOLAR WIND SIGNATURE FROM THE SEP 16 CME/DSF EVENT HAS NOT YET BEEN SEEN AND ITS ARRIVAL IS BECOMING LESS LIKELY.
III. Event Probabilities 21 SEP to 23 SEP
Class M10%10%10%
Class X01%01%01%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       20 SEP 145
  Predicted   21 SEP-23 SEP  142/140/138
  90 Day Mean        20 SEP 164
V. Geomagnetic A Indices
OBSERVED AFR/AP 19 SEP  009/010
ESTIMATED AFR/AP 20 SEP  010/010
PREDICTED AFR/AP 21 SEP-23 SEP  010/015-010/012-010/010
VI. Geomagnetic Activity Probabilities 21 SEP to 23 SEP
A. Middle Latitudes
Active20%10%05%
Minor storm05%01%01%
Major-severe storm01%01%01%
B. High Latitudes
Active20%10%10%
Minor storm05%05%05%
Major-severe storm01%01%01%

All times in UTC

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