Viewing archive of Friday, 17 December 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 Dec 17 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 351 Issued at 2200Z on 17 DEC 1999

IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z

SOLAR ACTIVITY WAS LOW. REGION 8798 (S13E21) PRODUCED SEVERAL C-CLASS X-RAY EVENTS DURING THE PERIOD. THE LASCO SPACECRAFT OBSERVED A CME CORRESPONDING WITH A C4/1F AT 17/0935Z FROM REGION 8798. THIS REGION REMAINS THE LARGEST REGION ON THE SOLAR DISK WITH AN AREA OF 550 MILLIONTHS AND CONTAINS A DKC BETA-GAMMA-DELTA SPOT GROUP. REGION 8803 (S13E10) PRODUCED A LONG DURATION C1/SF AT 17/1750Z. TWO NEW REGIONS WERE NUMBERED TODAY AS REGION 8805 (N18W27) AND REGION 8806 (N18E71).
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW. REGION 8798 CONTINUES TO HAVE THE POTENTIAL TO PRODUCE AN ISOLATED M-CLASS EVENT THROUGH THE PERIOD.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE QUIET TO UNSETTLED THROUGH THE FORECAST PERIOD.
III. Event Probabilities 18 DEC to 20 DEC
Class M40%40%40%
Class X10%10%10%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       17 DEC 201
  Predicted   18 DEC-20 DEC  210/195/190
  90 Day Mean        17 DEC 169
V. Geomagnetic A Indices
OBSERVED AFR/AP 16 DEC  006/005
ESTIMATED AFR/AP 17 DEC  008/008
PREDICTED AFR/AP 18 DEC-20 DEC  008/008-008/010-010/012
VI. Geomagnetic Activity Probabilities 18 DEC to 20 DEC
A. Middle Latitudes
Active10%10%10%
Minor storm05%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Active10%15%15%
Minor storm05%10%10%
Major-severe storm01%05%05%

All times in UTC

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