Viewing archive of Sunday, 19 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 19 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 262 Issued at 2200Z on 19 SEP 1999

IA. Analysis of Solar Active Regions and Activity from 18-2100Z to 19-2100Z

SOLAR ACTIVITY WAS LOW. REGIONS 8699 (N23W78) AND 8700 (N12W05) CONTINUED TO PRODUCE C-CLASS SUBFLARES. THE LARGEST FLARE OF THE PAST DAY WAS A C4/SF AT 19/1440UT IN REGION 8699. NEITHER REGION APPEARS SIGNIFICANTLY COMPLEX. NEW REGION 8706 (N19E77) APPEARS TO BE RETURNING REGION 8681 WHICH LEFT THE DISK LAST ROTATION AS A DECAYING SUNSPOT GROUP.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW TO MODERATE. C-CLASS FLARES ARE LIKELY IN REGIONS 8699 AND 8700. REGION 8700 IS THE BEST CANDIDATE FOR AN ISOLATED M-CLASS FLARE.
IIA. Geophysical Activity Summary 18-2100Z to 19-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. THE GREATER THAN 2 MEV ELECTRON FLUX AT GEOSYNCHRONOUS ORBIT WAS HIGH.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO REACH ACTIVE TO STORM LEVELS BY THE END OF SEP 20 DUE TO A CME/DSF OBSERVED ON SEP 16. THE FIELD SHOULD RETURN TO QUIET TO UNSETTLED CONDITIONS BY THE END OF THE THREE-DAY FORECAST PERIOD.
III. Event Probabilities 20 SEP to 22 SEP
Class M15%15%15%
Class X01%01%01%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       19 SEP 149
  Predicted   20 SEP-22 SEP  146/144/142
  90 Day Mean        19 SEP 164
V. Geomagnetic A Indices
OBSERVED AFR/AP 18 SEP  013/016
ESTIMATED AFR/AP 19 SEP  015/015
PREDICTED AFR/AP 20 SEP-22 SEP  030/030-015/015-010/012
VI. Geomagnetic Activity Probabilities 20 SEP to 22 SEP
A. Middle Latitudes
Active50%30%20%
Minor storm30%10%05%
Major-severe storm10%05%01%
B. High Latitudes
Active50%30%20%
Minor storm30%10%05%
Major-severe storm10%05%01%

All times in UTC

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