Viewing archive of Wednesday, 15 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 15 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 258 Issued at 2200Z on 15 SEP 1999

IA. Analysis of Solar Active Regions and Activity from 14-2100Z to 15-2100Z

SOLAR ACTIVITY WAS LOW. A LONG DURATION OPTICALLY UNCORRELATED C2.9 X-RAY EVENT WAS THE LARGEST EVENT OF THE PERIOD. INFREQUENT MINOR C-CLASS X-RAY EVENTS WERE OBSERVED, MOSTLY WITHOUT OPTICAL CORRELATION. REGION 8700 (N14E45) APPEARS AS THE MOST ACTIVE REGION ON THE VISIBLE DISK, UNDERGOING SEVERAL BRIGHTNESS FLUCTUATIONS AND SUBFLARES. REGION 8690 (N15W48) CONTINUES TO SLOWLY GROW AND APPEARS TO HAVE BECOME MORE MAGNETICALLY COMPLEX. REMAINING REGIONS WERE STABLE OR IN DECAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO CONTINUE AT LOW LEVELS. REGIONS 8690 AND 8700 WILL LIKELY PRODUCE C-CLASS EVENTS WITH A SMALL CHANCE FOR AN ISOLATED M-CLASS FLARE.
IIA. Geophysical Activity Summary 14-2100Z to 15-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE PRIOR TO A SHOCK ARRIVAL AT 15/0700Z. A SHORT PERIOD OF SUSTAINED SOUTHWARD BZ WITH A 700 KM/S WINDSPEED FOLLOWED THE SHOCK ARRIVAL AND RESULTED IN MINOR STORM CONDITIONS AT MID LATITUDES WITH SEVERE STORMING AT HIGH LATITUDES. QUIET TO ACTIVE CONDITIONS RETURNED TO ALL LATITUDES AFTER 15/1200UT. A SUDDEN IMPULSE OF 8NT WAS OBSERVED AT 15/2019UT.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE AT QUIET TO ACTIVE LEVELS DURING DAYTIME HOURS AND ACTIVE TO MINOR STORM LEVELS DURING LOCAL NIGHTTIME. THIS DISTURBANCE WILL BEGIN TO SUBSIDE ON DAY ONE THROUGH DAY TWO. QUIET TO UNSETTLED CONDITIONS ARE LIKELY ON DAY THREE.
III. Event Probabilities 16 SEP to 18 SEP
Class M15%15%15%
Class X05%05%05%
Proton05%05%05%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       15 SEP 155
  Predicted   16 SEP-18 SEP  160/165/170
  90 Day Mean        15 SEP 164
V. Geomagnetic A Indices
OBSERVED AFR/AP 14 SEP  022/023
ESTIMATED AFR/AP 15 SEP  026/030
PREDICTED AFR/AP 16 SEP-18 SEP  022/020-012/015-008/012
VI. Geomagnetic Activity Probabilities 16 SEP to 18 SEP
A. Middle Latitudes
Active50%35%25%
Minor storm30%15%10%
Major-severe storm05%05%05%
B. High Latitudes
Active60%40%30%
Minor storm30%20%10%
Major-severe storm10%05%05%

All times in UTC

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