Viewing archive of Sunday, 27 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 27 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 178 Issued at 2200Z on 27 JUN 1999

IA. Analysis of Solar Active Regions and Activity from 26-2100Z to 27-2100Z

SOLAR ACTIVITY WAS MODERATE. REGION 8592 (N22W33), A SIMPLE SINGLE SPOT HSX GROUP, PRODUCED AN M1/2N FLARE TODAY AT 0844Z. THE EVENT WAS ACCOMPANIED BY A TYPE IV RADIO SWEEP. NEW REGION 8611 (S26E60) EMERGED TODAY AND PRODUCED SOME SUBFLARE ACTIVITY. REGION 8598 (N23W11) CONTINUES TO BE THE LARGEST REGION ON THE DISK. THERE IS EVIDENCE OF EMERGING NEGATIVE MAGNETIC FLUX IN THE MIDDLE OF A STRONG POSITIVE POLARITY FIELD WHICH HAS LED TO THE FORMATION OF A DELTA SPOT NEAR THE CENTER OF THIS EXTENDED SUNSPOT REGION. A VERY SLOW, LONG DURATION RISE AND DECAY IN THE X-RAY FLUX OCCURRED BETWEEN 1815-2030Z, PEAKING AT THE C3 LEVEL; THE EVENT WAS ASSOCIATED WITH SUBFAINT INTENSITY PLAGE IN REGION 8598. REGION 8602 (N17E22) AND 8603 (S16E29) ARE ALSO OF RESPECTABLE SIZE; BOTH REGIONS PRODUCED A COUPLE SUBFLARES TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE MODERATE. REGION 8598 SHOWS GOOD POTENTIAL FOR PRODUCING M-CLASS FLARES. REGIONS 8602, 8603, AND 8606 COULD ALSO POSSIBLY CONTRIBUTE AN M-FLARE. THERE IS A POSSIBILITY FOR A MAJOR FLARE OR PROTON PRODUCING FLARE FROM 8598.
IIA. Geophysical Activity Summary 26-2100Z to 27-2100Z
THE GEOMAGNETIC FIELD RANGED FROM QUIET TO ACTIVE LEVELS, WITH SOME MINOR STORM INTERVALS AT HIGH LATITUDES. AN INITIALLY QUIET TO UNSETTLED GEOMAGNETIC FIELD BECAME MORE DISTURBED AFTER 1200Z; AFTER WHICH MIDDLE LATITUDES WERE MOSTLY ACTIVE AND HIGH LATITUDES WERE AT ACTIVE TO MINOR STORM LEVELS. ACE OBSERVATIONS SHOW AN OSCILLATING BZ COMPONENT WHICH BEGAN TO HAVE SOME NEGATIVE INTERVALS AFTER 0900Z.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO PERSIST AT ACTIVE LEVELS FOR THE NEXT 12 HOURS, AFTER WHICH UNSETTLED LEVELS ARE EXPECTED TO PREVAIL. UNSETTLED WITH A POSSIBILITY FOR ACTIVE IS FORECAST FOR THE SECOND DAY BECAUSE A NEW DISTURBANCE IS POSSIBLE ON THE 29TH DUE TO THE PARTIAL HALO CORONAL MASS EJECTION THAT OCCURRED ON THE 24TH. GENERALLY UNSETTLED CONDITIONS ARE EXPECTED TO PREDOMINATE ON THE THIRD DAY.
III. Event Probabilities 28 JUN to 30 JUN
Class M75%75%75%
Class X20%20%20%
Proton25%25%25%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       27 JUN 207
  Predicted   28 JUN-30 JUN  200/200/200
  90 Day Mean        27 JUN 143
V. Geomagnetic A Indices
OBSERVED AFR/AP 26 JUN  014/017
ESTIMATED AFR/AP 27 JUN  018/020
PREDICTED AFR/AP 28 JUN-30 JUN  015/015-015/010-010/010
VI. Geomagnetic Activity Probabilities 28 JUN to 30 JUN
A. Middle Latitudes
Active35%35%20%
Minor storm15%15%05%
Major-severe storm05%05%01%
B. High Latitudes
Active35%35%30%
Minor storm20%20%10%
Major-severe storm10%10%05%

All times in UTC

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