Viewing archive of Thursday, 20 May 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 May 20 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 140 Issued at 2200Z on 20 MAY 1999

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

SOLAR ACTIVITY WAS LOW. THE PERIOD WAS CHARACTERIZED BY A NUMBER OF WEAK, OPTICALLY UNCORRELATED C-CLASS X-RAY FLARES. REGION 8549 (N25W59) EMERGED AND PRODUCED SEVERAL OPTICAL SUB-FLARES. REGION 8550 (S14E74) WAS ALSO NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW, WITH A SLIGHT CHANCE OF ISOLATED M-CLASS X-RAY FLARES.
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 REMAIN QUIET TO UNSETTLED.
III. Event Probabilities 21 MAY to 23 MAY
Class M20%20%20%
Class X01%01%01%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       20 MAY 143
  Predicted   21 MAY-23 MAY  140/140/140
  90 Day Mean        20 MAY 128
V. Geomagnetic A Indices
OBSERVED AFR/AP 19 MAY  008/010
ESTIMATED AFR/AP 20 MAY  008/010
PREDICTED AFR/AP 21 MAY-23 MAY  005/008-005/008-008/010
VI. Geomagnetic Activity Probabilities 21 MAY to 23 MAY
A. Middle Latitudes
Active20%20%25%
Minor storm05%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Active25%25%25%
Minor storm10%10%10%
Major-severe storm05%05%05%

All times in UTC

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