Viewing archive of Monday, 13 September 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 Sep 13 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 256 Issued at 2200Z on 13 SEP 1999

IA. Analysis of Solar Active Regions and Activity from 12-2100Z to 13-2100Z

SOLAR ACTIVITY WAS LOW. THE LARGEST EVENT THIS PERIOD WAS A C4/SF FROM REGION 8699 (N21E01), WHICH OCCURRED AT 13/0846UT. THE RAPID GROWTH NOTED IN THIS REGION OVER THE PAST 48 HOURS SUBSIDED DURING THE LATTER HALF OF THIS PERIOD. THE REGION RETAINS A MODERATELY COMPLEX MAGNETIC STRUCTURE BUT HAS RELATIVELY SMALL WHITE LIGHT AERIAL COVERAGE. REGION 8690 (N14W06) EXHIBITED GROWTH, PRODUCED OCCASIONAL SUBFLARES LATE IN THE PERIOD AND WAS THE LIKELY SOURCE FOR A TYPE II SWEEP AT 13/1622UT. NEW REGION 8701 (N18E13), WAS NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW. SEVERAL EXISTING REGIONS HAVE C-CLASS FLARE POTENTIAL WITH A SMALL CHANCE OF AN ISOLATED M-CLASS EVENT.
IIA. Geophysical Activity Summary 12-2100Z to 13-2100Z
THE GEOMAGNETIC FIELD WAS AT UNSETTLED TO MINOR STORM CONDITIONS WITH AN ISOLATED MAJOR STORM PERIOD OBSERVED BETWEEN 13/0000 - 0300Z. THIS DISTURBANCE IS LIKELY ASSOCIATED WITH A HIGH-SPEED CORONAL HOLE WIND STREAM.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO CONTINUE AT UNSETTLED TO MINOR STORM LEVELS WITH THE MOST DISTURBED CONDITIONS EXPECTED DURING LOCAL NIGHTTIME HOURS.
III. Event Probabilities 14 SEP to 16 SEP
Class M20%20%20%
Class X05%05%05%
Proton05%05%05%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       13 SEP 155
  Predicted   14 SEP-16 SEP  160/165/170
  90 Day Mean        13 SEP 164
V. Geomagnetic A Indices
OBSERVED AFR/AP 12 SEP  020/026
ESTIMATED AFR/AP 13 SEP  032/040
PREDICTED AFR/AP 14 SEP-16 SEP  025/025-018/015-018/015
VI. Geomagnetic Activity Probabilities 14 SEP to 16 SEP
A. Middle Latitudes
Active50%50%40%
Minor storm20%20%15%
Major-severe storm10%10%05%
B. High Latitudes
Active60%60%50%
Minor storm30%30%25%
Major-severe storm10%10%05%

All times in UTC

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