Viewing archive of Monday, 26 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 26 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 207 Issued at 2200Z on 26 JUL 1999

IA. Analysis of Solar Active Regions and Activity from 25-2100Z to 26-2100Z

SOLAR ACTIVITY BECAME LOW. THE LARGEST EVENTS OF THE PERIOD WERE LOW LEVEL C-CLASS BURSTS. REGION 8636 (N21W41) PRODUCED SEVERAL SUBFLARES, DECREASED SLIGHTLY IN SIZE, AND APPEARED TO ONCE AGAIN SIMPLIFY MAGNETICALLY. REGION 8645 (S27E47) REMAINED PREDOMINANTLY STABLE. REGION 8639 (N38W99) PRODUCED FREQUENT SURGING FROM BEHIND THE LIMB BUT PRODUCED NO DISCERNIBLE BURSTS. POST EVENT ANALYSIS OF THE M2 FLARE GENERATED BY THIS REGION AT 25/1338Z INDICATED A LARGE CORONAL MASS EJECTION ACCOMPANIED THE FLARE. HOWEVER, IT WAS DETERMINED BY SOHO SCIENTISTS THAT THIS CME WAS NOT EARTH DIRECTED.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS FORECAST TO BE LOW TO MODERATE. BOTH REGIONS 8636 AND 8645 ARE CAPABLE OF PRODUCING OCCASIONAL M-CLASS EVENTS. REGION 8636 COULD PRODUCE AN ISOLATED X-CLASS EVENT BUT THAT LIKELIHOOD IS DECREASING AS THE REGION SLOWLY DECAYS.
IIA. Geophysical Activity Summary 25-2100Z to 26-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD REMAIN AT GENERALLY QUIET TO UNSETTLED LEVELS FOR THE NEXT THREE DAYS. ISOLATED ACTIVE PERIODS ARE POSSIBLE DURING THAT TIME.
III. Event Probabilities 27 JUL to 29 JUL
Class M75%75%75%
Class X15%15%15%
Proton15%15%15%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       26 JUL 172
  Predicted   27 JUL-29 JUL  172/172/174
  90 Day Mean        26 JUL 158
V. Geomagnetic A Indices
OBSERVED AFR/AP 25 JUL  008/008
ESTIMATED AFR/AP 26 JUL  008/007
PREDICTED AFR/AP 27 JUL-29 JUL  008/007-010/012-008/008
VI. Geomagnetic Activity Probabilities 27 JUL to 29 JUL
A. Middle Latitudes
Active10%30%15%
Minor storm05%15%05%
Major-severe storm01%05%01%
B. High Latitudes
Active10%30%20%
Minor storm05%15%05%
Major-severe storm01%05%01%

All times in UTC

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