Viewing archive of Saturday, 25 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 25 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 359 Issued at 2200Z on 25 DEC 1999

IA. Analysis of Solar Active Regions and Activity from 24-2100Z to 25-2100Z

SOLAR ACTIVITY WAS LOW. TODAY'S ACTIVITY CONSISTED OF OCCASIONAL C-CLASS FLARES, MOST OF WHICH WERE FROM REGIONS 8806 (N20W23) AND NEW REGION 8810 (N36E64). TODAY'S LARGEST EVENT WAS A C6 X-RAY FLARE AT 1129Z THAT WAS NOT OBSERVED OPTICALLY. REGION 8806 HAS NOT SHOWN MUCH CHANGE FROM YESTERDAY: THE GROUP STILL HAS A DELTA CONFIGURATION IN THE PRESENCE OF STRONG MAGNETIC FIELDS, BUT IS NONETHELESS REMARKABLY STABLE. NEW REGION 8810 IS AN E-TYPE GROUP (MORE THAN 11 DEGREES WITH PENUMBRA ON LEADER AND TRAILERS) AND SHOWS OCCASIONAL FLUCTUATIONS AND SUBFLARES.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW TO MODERATE. THERE CONTINUES TO BE A FAIR CHANCE FOR AN ISOLATED M-CLASS EVENT FROM REGION 8806, AND A SLIGHT CHANCE FOR A MAJOR FLARE OR PROTON PRODUCING FLARE.
IIA. Geophysical Activity Summary 24-2100Z to 25-2100Z
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO ACTIVE LEVELS. THE ACTIVE PERIODS WERE ISOLATED SUBSTORMS BETWEEN 0600-0900Z AND 1200-1500Z.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE MOSTLY UNSETTLED TOMORROW BUT THERE IS A CHANCE FOR ACTIVE LEVELS. A SMALL GEOMAGNETIC RESPONSE IS POSSIBLE FROM A CME THAT OCCURRED ON 22 DECEMBER. CONDITIONS SHOULD DECLINE TO QUIET TO UNSETTLED BY THE 27TH AND 28TH.
III. Event Probabilities 26 DEC to 28 DEC
Class M60%60%60%
Class X15%15%15%
Proton15%15%15%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       25 DEC 178
  Predicted   26 DEC-28 DEC  175/175/170
  90 Day Mean        25 DEC 175
V. Geomagnetic A Indices
OBSERVED AFR/AP 24 DEC  011/010
ESTIMATED AFR/AP 25 DEC  013/015
PREDICTED AFR/AP 26 DEC-28 DEC  012/020-007/010-005/007
VI. Geomagnetic Activity Probabilities 26 DEC to 28 DEC
A. Middle Latitudes
Active30%10%10%
Minor storm15%05%05%
Major-severe storm05%01%01%
B. High Latitudes
Active35%10%10%
Minor storm15%05%05%
Major-severe storm10%01%01%

All times in UTC

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