Viewing archive of Saturday, 17 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 17 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 198 Issued at 2200Z on 17 JUL 1999

IA. Analysis of Solar Active Regions and Activity from 16-2100Z to 17-2100Z

SOLAR ACTIVITY WAS LOW. THE TWO ACTIVE REGIONS WERE 8535 (N44W92) AND 8536 (N20E73). BOTH REGIONS PRODUCED SEVERAL OPTICAL SUBFLARES DURING THE DAY. REGION 8535 ALSO PRODUCED 2 C-CLASS EVENTS, THE LARGEST WAS A C3/SF AT 17/1631UT. REGION 8536 WAS NUMBERED TODAY. IT APPEARS TO BE RETURNING REGION 8539. THAT REGION PRODUCED SEVERAL C AND M-CLASS EVENTS DURING THE LAST ROTATION.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW TO MODERATE. ALTHOUGH REGION 8535 WILL ROTATE OFF OF THE DISK THIS PERIOD, REGION 8536 COULD PRODUCE ISOLATED M-CLASS EVENTS.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
THE GEOMAGNETIC FIELD WAS QUIET.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO CONTINUE TO BE QUIET FOR THE FIRST TWO DAYS OF THE PERIOD WITH POSSIBLE UNSETTLED CONDITIONS ON THE THIRD DAY.
III. Event Probabilities 18 JUL to 20 JUL
Class M50%50%50%
Class X05%05%05%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       17 JUL 137
  Predicted   18 JUL-20 JUL  150/155/160
  90 Day Mean        17 JUL 152
V. Geomagnetic A Indices
OBSERVED AFR/AP 16 JUL  005/005
ESTIMATED AFR/AP 17 JUL  005/005
PREDICTED AFR/AP 18 JUL-20 JUL  005/007-005/007-010/010
VI. Geomagnetic Activity Probabilities 18 JUL to 20 JUL
A. Middle Latitudes
Active10%10%20%
Minor storm01%01%05%
Major-severe storm01%01%01%
B. High Latitudes
Active15%15%20%
Minor storm01%01%05%
Major-severe storm01%01%01%

All times in UTC

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