Viewing archive of Sunday, 21 February 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 Feb 21 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 052 Issued at 2200Z on 21 FEB 1999

IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z

SOLAR ACTIVITY WAS MODERATE. THIS WAS DUE TO A SINGLE M-CLASS EVENT. A LONG DURATION (1 HOUR) M1/SF AT 21/1345UT FROM REGION 8462 (N20W79). THE ONLY OTHER EVENT OF NOTICE WAS AN OPTICALLY UNCORRELATED C8 X-RAY FLARE AT 21/0950UT. REGION 8462 WAS THE MOST ACTIVE REGION. RGN 8464 (N18W53) PRODUCED A SINGLE SUBFLARE. ALL THE REST OF THE REGIONS WERE QUIET AND STABLE. NEW REGION 8469 (N15W18) EMERGED AS A 4 SPOT CSO BETA GROUP.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW. THERE IS SLIGHT CHANCE OF REGION 8462 PRODUCING ANOTHER ISOLATED M-CLASS EVENT.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET. THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT REACHED THRESHOLD LEVELS AT 21/1700 AND REMAINED AT THAT LEVEL FOR THE REST OF THE PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO VARY FROM QUIET TO ACTIVE LEVELS FOR THE NEXT 2 DAYS. A HIGH SPEED STREAM FROM A WELL POSITIONED CORONAL HOLE MAY AFFECT THE NEAR EARTH ENVIRONS IN THE NEXT 24-48 HOURS. CONDITIONS SHOULD RETURN TO QUIET TO UNSETTLED ON THE 3RD DAY.
III. Event Probabilities 22 FEB to 24 FEB
Class M30%25%20%
Class X01%01%01%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       21 FEB 147
  Predicted   22 FEB-24 FEB  145/140/135
  90 Day Mean        21 FEB 147
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 FEB  002/005
ESTIMATED AFR/AP 21 FEB  005/010
PREDICTED AFR/AP 22 FEB-24 FEB  005/012-015/017-010/008
VI. Geomagnetic Activity Probabilities 22 FEB to 24 FEB
A. Middle Latitudes
Active15%30%20%
Minor storm05%10%05%
Major-severe storm01%01%01%
B. High Latitudes
Active20%40%30%
Minor storm05%15%10%
Major-severe storm01%01%01%

All times in UTC

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