Viewing archive of Monday, 4 May 1998

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 1998 May 04 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

:::::::::: CORRECTED COPY :::::::::: SDF Number 124 Issued at 2200Z on 04 MAY 1998

IA. Analysis of Solar Active Regions and Activity from 03-2100Z to 04-2100Z

SOLAR ACTIVITY HAS BEEN MODERATE FOR THE PAST 24 HOURS. AT 03/2129Z AN M1/1B TENFLARE (810 FLUX UNITS, 8 MINUTES DURATION) ACCOMPANIED BY A MAJOR TYPE IV SWEEP, WAS ASSOCIATED WITH A 1B FLARE IN REGION 8210 (S17W50) AND A SIMULTANEOUS SUBFAINT FLARE IN REGION 8214 (N27E18). SYMPATHETIC FLARING HAS BEEN A CHARACTERISTIC OF THESE TWO WIDELY SEPARATED REGIONS FOR THE PAST SEVERAL DAYS. REGION 8210 HAS FRAGMENTED AND SHOWN CONSIDERABLE DECAY, BUT REGION 8214 IS STILL GROWING IN WHITE LIGHT ALTHOUGH IT HAS NOT DEVELOPED THE MAGNETIC COMPLEXITY USUALLY ASSOCIATED WITH ENERGETIC EVENTS. AN ACTIVE PROMINENCE ON THE SOUTHEAST LIMB WAS OBSERVED, BUT THE REMAINDER OF THE DISK AND LIMBS WERE QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE MODERATE BASED ON THE COMBINED FLARE POTENTIAL IN REGIONS 8210 AND 8214. THE PROBABILITY OF X-CLASS ACTIVITY HAS LESSENED WITH THE RECENT SIMPLIFICATION OF REGION 8210, BUT ADDITIONAL GROWTH IN REGION 8214 COULD BE A PRECURSOR TO NEW MAJOR EVENTS.
IIA. Geophysical Activity Summary 03-2100Z to 04-2100Z
GEOMAGNETIC ACTIVITY HAS RANGED FROM UNSETTLED TO SEVERE STORM LEVELS FOR THE PAST 24 HOURS. THIS DISTURBANCE IS ASSUMED TO BE RELATED TO COMPLEX SOLAR WIND STRUCTURES ASSOCIATED WITH A SERIES OF ENERGETIC SOLAR EVENTS BEGINNING ON 29 APRIL, AND ESPECIALLY AN X1 X-RAY EVENT THAT REACHED MAXIMUM 02/1342 UT. A SHOCK PASSED THE ACE SPACECRAFT AT APPROXIMATELY 04/0229 UT THAT WAS OBSERVED AT EARTH APPROXIMATELY 30 MINUTES LATER. THEREAFTER, A TWO-HOUR PERIOD OF VERY STRONG (ABOUT 40 NT) SOUTHWARD SOLAR WIND MAGNETIC FIELD WAS OBSERVED, RESULTING IN K INDICES OF 8 IN BOULDER BETWEEN 03-09 UT AND REPORTS OF AURORAL SIGHTINGS IN THE NORTHERN UNITED STATES. THE ENERGETIC PROTON EVENT THAT BEGAN ON 02/1405 ENDED 04/0310 UT.
IIB. Geophysical Activity Forecast
GEOMAGNETIC ACTIVITY IS EXPECTED TO EXPERIENCE PERIODS AT STORM LEVELS FOR THE NEXT 24 HOURS. WHILE IT IS CLEAR THAT THE LEADING PORTION OF THE CORONAL MASS EJECTION ASSOCIATED WITH THE X1 FLARE HAS ARRIVED, IT IS NOT CERTAIN WHETHER THE CORE OF THE EJECTION WILL YET ARRIVE. THEREFORE, STORM LEVEL WARNINGS ARE ADVISED THROUGH 5 MAY. THE DISTURBANCE IS EXPECTED TO END BY 7 MAY UNLESS NEW SOLAR EVENTS OCCUR.
III. Event Probabilities 05 MAY to 07 MAY
Class M50%50%50%
Class X10%10%10%
Proton10%10%10%
PCAFYELLOW
IV. Penticton 10.7 cm Flux
  Observed       04 MAY 121
  Predicted   05 MAY-07 MAY  135/140/145
  90 Day Mean        04 MAY 105
V. Geomagnetic A Indices
OBSERVED AFR/AP 03 MAY  037/057
ESTIMATED AFR/AP 04 MAY  086/100
PREDICTED AFR/AP 05 MAY-07 MAY  050/060-025/045-010/025
VI. Geomagnetic Activity Probabilities 05 MAY to 07 MAY
A. Middle Latitudes
Active10%30%20%
Minor storm20%25%05%
Major-severe storm60%20%01%
B. High Latitudes
Active10%30%50%
Minor storm25%30%20%
Major-severe storm65%20%05%

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