Viewing archive of Saturday, 31 July 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 Jul 31 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 212 Issued at 2200Z on 31 JUL 1999

IA. Analysis of Solar Active Regions and Activity from 30-2100Z to 31-2100Z

SOLAR ACTIVITY WAS LOW. SEVERAL C-CLASS FLARES WERE PRODUCED BY REGION 8651 (N25E23). THE LARGEST WAS A C5/SF AT 30/2335Z. THIS REGION REMAINS THE LARGEST REGION ON THE DISK AND IS AN E-TYPE GROUP WITH A WHITE LIGHT AREA OF AROUND 730 MILLIONTHS. THE SECOND MOST INTERESTING GROUP IS REGION 8645 (S25W16) WHICH ALSO PRODUCED SEVERAL C-CLASS FLARES. THIS REGION HAS MAINTAINED A WHITE LIGHT AREA OF AROUND 600 MILLIONTHS AND IS A F-TYPE GROUP. NEW REGION 8654 (N19W18) WAS NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW TO MODERATE. REGIONS 8645 AND 8651 HAVE THE POTENTIAL FOR PRODUCING ISOLATED M-CLASS EVENTS.
IIA. Geophysical Activity Summary 30-2100Z to 31-2100Z
THE GEOMAGNETIC FIELD WAS AT QUIET TO SEVERE STORM CONDITIONS. MAJOR TO SEVERE STORMS WERE PRESENT EARLY IN THE PERIOD WITH UNSETTLED TO ACTIVE LEVELS PREDOMINATE TOWARD THE END.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE UNSETTLED WITH PERIODS OF ACTIVE CONDITIONS THE FIRST DAY OF THE FORECAST. THE SECOND AND THIRD DAYS ARE EXPECTED TO RETURN TO QUIET TO UNSETTLED CONDITIONS.
III. Event Probabilities 01 AUG to 03 AUG
Class M80%80%80%
Class X15%15%15%
Proton10%10%10%
PCAFYELLOW
IV. Penticton 10.7 cm Flux
  Observed       31 JUL 201
  Predicted   01 AUG-03 AUG  195/190/190
  90 Day Mean        31 JUL 162
V. Geomagnetic A Indices
OBSERVED AFR/AP 30 JUL  041/036
ESTIMATED AFR/AP 31 JUL  018/020
PREDICTED AFR/AP 01 AUG-03 AUG  015/012-008/008-008/008
VI. Geomagnetic Activity Probabilities 01 AUG to 03 AUG
A. Middle Latitudes
Active25%15%15%
Minor storm05%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Active30%20%20%
Minor storm10%05%05%
Major-severe storm05%01%01%

All times in UTC

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