Viewing archive of Wednesday, 4 August 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 Aug 04 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 216 Issued at 2200Z on 04 AUG 1999

IA. Analysis of Solar Active Regions and Activity from 03-2100Z to 04-2100Z

SOLAR ACTIVITY REMAINED AT HIGH LEVELS. REGION 8647 (S18W75) PRODUCED AN M6/1N FLARE AT 04/0557Z ASSOCIATED WITH A WEAK TYPE II RADIO SWEEP (EST. SHOCK VELOCITY 400 KM/SEC) AND A 230 SFU TENFLARE. IT ALSO PRODUCED AN M1/SF FLARE AT 04/1607Z. THIS REGION SHOWED LITTLE CHANGE DURING THE PERIOD AND WAS OF MODERATE SIZE AND MAGNETIC COMPLEXITY. REGION 8651 (N25W31) REMAINED A LARGE F-TYPE GROUP OF MODERATE MAGNETIC COMPLEXITY, BUT APPEARED TO BE SLOWLY DECAYING. IT PRODUCED TWO SUBFLARES DURING THE PERIOD. REGION 8645 (S26W66) REMAINED MODERATE IN SIZE AND MAGNETIC COMPLEXITY AND SHOWED LITTLE CHANGE AS IT PRODUCED ISOLATED SUBFLARES. NEW REGION 8660 (S34W25), A SMALL B-TYPE GROUP, WAS NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE MODERATE. ISOLATED M-CLASS FLARES ARE POSSIBLE FROM REGIONS 8645, 8647, AND 8651. THERE IS ALSO A CHANCE FOR ANOTHER MAJOR FLARE FROM REGION 8647.
IIA. Geophysical Activity Summary 03-2100Z to 04-2100Z
THE GEOMAGNETIC FIELD WAS AT QUIET TO ACTIVE LEVELS. A SUDDEN IMPULSE OCCURRED AT 04/0225Z (25 NT, AS MEASURED BY THE BOULDER USGS MAGNETOMETER). FIELD ACTIVITY INCREASED FOLLOWING THE IMPULSE WITH ACTIVE LEVELS DETECTED DURING THE 04/0300 - 0600Z INTERVAL. ACTIVITY DECREASED TO QUIET TO UNSETTLED LEVELS DURING THE REMAINDER OF THE PERIOD.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE AT QUIET TO UNSETTLED LEVELS THROUGH THE PERIOD. THERE APPEARED TO BE NO EARTH-DIRECTED CORONAL MASS EJECTIONS ASSOCIATED WITH THE MAJOR FLARES OF 02 AND 04 AUGUST.
III. Event Probabilities 05 AUG to 07 AUG
Class M80%70%50%
Class X20%15%10%
Proton10%10%05%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       04 AUG 200
  Predicted   05 AUG-07 AUG  195/185/175
  90 Day Mean        04 AUG 165
V. Geomagnetic A Indices
OBSERVED AFR/AP 03 AUG  005/008
ESTIMATED AFR/AP 04 AUG  012/015
PREDICTED AFR/AP 05 AUG-07 AUG  012/015-010/010-005/008
VI. Geomagnetic Activity Probabilities 05 AUG to 07 AUG
A. Middle Latitudes
Active25%20%15%
Minor storm05%05%01%
Major-severe storm01%01%01%
B. High Latitudes
Active25%25%15%
Minor storm10%10%05%
Major-severe storm01%01%01%

All times in UTC

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