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

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 168 Issued at 2200Z on 17 JUN 1999

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

SOLAR ACTIVITY BECAME MODERATE. DEPARTED REGION 8569 (N18W98) PRODUCED AN M3 AT 17/1730Z. THE BIG BEAR OBSERVATORY PROVIDED CONFIRMATION OF THE SOURCE REGION. A TYPE II WITH VELOCITY NEAR 600 KM/S AND MINOR CENTIMETRIC BURSTS ACCOMPANIED THIS EVENT. THE MAUNA LOA GROUND-BASED CORONAGRAPH OBSERVED A FAINT CORONAL MASS EJECTION WITH THIS EVENT. REGION 8569 ALSO PRODUCED A C5 WITH AN ERUPTIVE PROMINENCE AT 17/0036Z. SMALL REGIONS 8590 (S21W14) AND 8591 (N12E15) EMERGED ON THE DISK. REGION 8590 EMERGED SLIGHTLY AHEAD OF EXISTING REGION 8588 (S22W05).
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD BE GENERALLY LOW FOR THE NEXT THREE DAYS. THERE IS A SLIGHT POSSIBILITY OF AN M-CLASS EVENT DURING THAT PERIOD FROM CURRENT DISK REGIONS AND PREVIOUSLY ACTIVE REGIONS DUE TO ROTATE OVER THE NORTHEAST LIMB. DEPARTED REGION 8569 WILL BECOME LESS OF A THREAT AS IT ROTATES FARTHER BEYOND THE WEST LIMB.
IIA. Geophysical Activity Summary 16-2100Z to 17-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO SLIGHTLY UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD BE QUIET TO UNSETTLED FOR THE NEXT THREE DAYS.
III. Event Probabilities 18 JUN to 20 JUN
Class M15%15%15%
Class X05%05%05%
Proton05%05%05%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       17 JUN 147
  Predicted   18 JUN-20 JUN  150/152/154
  90 Day Mean        17 JUN 136
V. Geomagnetic A Indices
OBSERVED AFR/AP 16 JUN  005/007
ESTIMATED AFR/AP 17 JUN  005/010
PREDICTED AFR/AP 18 JUN-20 JUN  007/008-010/012-007/010
VI. Geomagnetic Activity Probabilities 18 JUN to 20 JUN
A. Middle Latitudes
Active05%10%05%
Minor storm01%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Active10%20%10%
Minor storm05%10%05%
Major-severe storm01%05%01%

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