Viewing archive of Tuesday, 18 April 2000

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 2000 Apr 18 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 109 Issued at 2200Z on 18 APR 2000

IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z

SOLAR ACTIVITY WAS LOW. REGION 8963 (N16E09) RAPIDLY EMERGED AS THE PRIMARY FLARE PRODUCING REGION ON THE VISIBLE DISK AND WAS RESPONSIBLE FOR THE THREE LARGEST EVENTS OF THE PERIOD. THE FIRST AND LARGEST EVENT WAS A C7/SF AT 18/0805UT, FOLLOWED BY A C4 FLARE WITH A TYPE II SWEEP AT 18/1153UT, AND FINALLY A C4/SF AT 18/1415UT. ALL EVENTS WERE ACCOMPANIED BY MINOR CENTIMETRIC BURSTS. THIS REGION, THOUGH QUITE ACTIVE, IS A RELATIVELY SMALL DAO GROUP WITH 80 MILLIONTHS OF WHITE LIGHT AREA. REGION 8955 (S22W19) HAS STABILIZED, PRODUCING ONLY OCCASIONAL MINOR C-CLASS FLARES. NEW REGION 8966 (S13E65) WAS NUMBERED TODAY. REMAINING REGIONS WERE QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW. REGIONS 8955 AND 8963 WILL LIKELY CONTINUE TO PRODUCE C-CLASS ACTIVITY.
IIA. Geophysical Activity Summary 17-2100Z to 18-2100Z
THE GEOMAGNETIC FIELD WAS MOSTLY QUIET WITH OCCASIONAL UNSETTLED PERIODS.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO REMAIN AT QUIET TO UNSETTLED LEVELS.
III. Event Probabilities 19 APR to 21 APR
Class M35%35%35%
Class X05%05%05%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       18 APR 160
  Predicted   19 APR-21 APR  160/165/170
  90 Day Mean        18 APR 183
V. Geomagnetic A Indices
OBSERVED AFR/AP 17 APR  011/014
ESTIMATED AFR/AP 18 APR  006/010
PREDICTED AFR/AP 19 APR-21 APR  008/012-010/015-005/008
VI. Geomagnetic Activity Probabilities 19 APR to 21 APR
A. Middle Latitudes
Active25%25%20%
Minor storm10%10%05%
Major-severe storm01%01%01%
B. High Latitudes
Active30%35%25%
Minor storm20%25%15%
Major-severe storm05%05%01%

All times in UTC

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