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

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 177 Issued at 2200Z on 26 JUN 1999

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

SOLAR ACTIVITY WAS MODERATE. REGION 8598 (N23E02) PRODUCED AN M2/2N AT 0512Z. THE GROUP CONTINUES TO BE THE DOMINANT REGION ON THE DISK AND PRODUCED ADDITIONAL C-CLASS FLARES DURING THE PAST 24 HOURS. REGION 8602 (N17E35) IS ALSO IMPRESSIVE LOOKING WITH BRIGHT, FLUCTUATING PLAGE BUT COULD ONLY PRODUCE A SUBFLARE. REGION 8596 (N22W12) WAS ALSO ACTIVE A CONTRIBUTED A C4/1N FLARE AT 1650Z.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE MODERATE. REGIONS 8598 AND 8602 ARE EXPECTED TO BE THE MAIN ACTIVITY CENTERS FOR THE NEXT THREE DAYS. THERE IS A SLIGHT CHANCE FOR MAJOR FLARE OR PROTON PRODUCING ACTIVITY FROM REGION 8598.
IIA. Geophysical Activity Summary 25-2100Z to 26-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. A SHOCK WAS SEEN AT THE ACE SPACECRAFT AT 0215Z AND WAS FOLLOWED BY A FEW HOURS OF MODERATELY NEGATIVE SOUTHWARD INTERPLANETARY FIELD. A 16 NT SUDDEN IMPULSE OCCURRED AT 0326Z AND WAS FOLLOWED BY A 12 HOUR PERIOD OF UNSETTLED TO ACTIVE GEOMAGNETIC CONDITIONS. A SECOND SHOCK WAS SEEN AT ACE AT 1925Z, FOLLOWED BY ANOTHER SUDDEN IMPULSE AT 2020Z WHICH MEASURED 38 NT IN BOULDER. AS OF FORECAST FILE TIME THE INTERPLANETARY MAGNETIC FIELD WAS ORIENTED NORTHWARDS.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE MOSTLY UNSETTLED FOR THE NEXT TWO DAYS. HOWEVER, THE NATURE OF THE PLASMA AND FIELDS BEHIND THE 20/1925Z SHOCK AT ACE IS CURRENTLY UNKNOWN AND COULD BE GEOEFFECTIVE. THEREFORE THERE IS A POSSIBILITY OF DISTURBED CONDITIONS FOR THE NEXT 12 HOURS. AN INCREASE IN GEOMAGNETIC ACTIVITY IS ALSO POSSIBLE ON THE THIRD DAY IN RESPONSE TO THE PARTIAL HALO CORONAL MASS EJECTION OF 24/1200Z.
III. Event Probabilities 27 JUN to 29 JUN
Class M55%55%55%
Class X15%15%15%
Proton20%20%20%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       26 JUN 200
  Predicted   27 JUN-29 JUN  205/205/205
  90 Day Mean        26 JUN 141
V. Geomagnetic A Indices
OBSERVED AFR/AP 25 JUN  002/005
ESTIMATED AFR/AP 26 JUN  014/012
PREDICTED AFR/AP 27 JUN-29 JUN  010/012-010/012-015/010
VI. Geomagnetic Activity Probabilities 27 JUN to 29 JUN
A. Middle Latitudes
Active20%20%30%
Minor storm05%05%10%
Major-severe storm01%01%05%
B. High Latitudes
Active25%25%35%
Minor storm10%10%15%
Major-severe storm01%01%10%

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