Viewing archive of Tuesday, 29 December 1998

Solar activity report

Report of Solar-Geophysical Activity 1998 Dec 29 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 363 Issued at 2200Z on 29 DEC 1998

IA. Analysis of Solar Active Regions and Activity from 28-2100Z to 29-2100Z

SOLAR ACTIVITY WAS MODERATE. REGION 8419 (N26W52) PRODUCED AN M2/1F FLARE AT 28/2338Z AND REGION 8421 (N26E00) PRODUCED AN M1/1F AT 28/2322Z. REGION 8419 WAS ACTIVE AT THE BEGINNING OF THE REPORTING PERIOD BUT BEGAN TO QUIET DOWN AROUND 29/0300Z. WHITE LIGHT OBSERVATIONS SHOW THE LOSS OF PENUMBRAL AREA IN THE TRAILING PORTION OF THE REGION. THE MAGNETIC CONFIGURATION HAS SIMPLIFIED TO A BETA-GAMMA CLASS. IN CONTRAST, REGION 8421 HAS SHOWN SIGNIFICANT GROWTH OVER THE PAST 24 HOURS AND BEGAN PRODUCING FREQUENT C-CLASS SUBFLARES DURING THE LAST 12 HOURS OF THE REPORTING PERIOD. WHITE LIGHT AND MAGNETIC OBSERVATIONS SHOW A LARGE, COMPACT SUNSPOT GROUP WITH AT LEAST ONE, AND POSSIBLY TWO DELTA CONFIGURATIONS. THE MAIN INVERSION LINE RUNS FROM EAST-NORTHEAST TO WEST-SOUTHWEST THROUGH THE REGION.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE MODERATE, BUT THERE IS A CHANCE FOR A MAJOR EVENT FROM REGION 8421 OVER THE NEXT THREE DAYS. IN PARTICULAR, CONTINUED FLUX EMERGENCE AND DEVELOPMENT OF SHEAR ALONG THE NEUTRAL LINE OF THIS REGION COULD LEAD TO SIGNFICANT FLARE ACTIVITY. REGION 8419 SEEMS TO BE MOSTLY STABLE, BUT POSES SOME THREAT OF PRODUCING AN ISOLATED LOW-LEVEL M-CLASS EVENT. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 28/2100Z TO 29/2100Z: THE GEOMAGNETIC FIELD HAS BEEN PREDOMINANTLY QUIET TO ACTIVE OVER THE PAST 24 HOURS, ALTHOUGH SOME HIGH LATITUDE SITES OBSERVED SHORT INTERVALS OF STORM LEVEL ACTIVITY. YESTERDAY'S VERY QUIET CONDITIONS CAME TO AN END AROUND 0730UT AFTER WHICH UNSETTLED TO ACTIVE LEVELS PREVAILED. A FEW HIGH-LATITUDE STATIONS SAW SUBSTORM EFFECTS BETWEEN 1000-1400Z, BUT THE DISTURBANCE WASN'T STRONG ENOUGH TO PRODUCE ACTIVE LEVELS AT MID-LATITUDES. THE LATTER PART OF THE DAY (FROM 1500-2100Z) WAS PREDOMINANTLY UNSETTLED WITH OCCASIONAL ACTIVE PERIODS AT THE HIGHER LATITUDE SITES. REAL-TIME SOLAR WIND OBSERVATIONS INDICATE SLIGHTLY ENHANCED DENSITY, VELOCITY AND MAGNETIC FIELDS, AND SOMEWHAT LOW TEMPERATURES, SUGGESTING THAT THE CURRENT ACTIVITY IS BEING CAUSED BY TRANSIENT MATERIAL IN THE SOLAR WIND.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE MOSTLY UNSETTLED WITH OCCASIONAL ACTIVE PERIODS OVER THE NEXT 24 HOURS. GENERALLY UNSETTLED CONDITIONS ARE LIKELY TO DOMINATE FOR THE SECOND AND THIRD DAYS AS THERE MAY BE SOME SHORT-LIVED EFFECTS FROM A SMALL, BUT FAVORABLY POSITIONED CORONAL HOLE.
III. Event Probabilities 30 DEC to 01 JAN
Class M70%70%70%
Class X20%20%20%
Proton15%15%20%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       29 DEC 183
  Predicted   30 DEC-01 JAN  180/175/165
  90 Day Mean        29 DEC 135
V. Geomagnetic A Indices
OBSERVED AFR/AP 28 DEC  003/005
ESTIMATED AFR/AP 29 DEC  012/011
PREDICTED AFR/AP 30 DEC-01 JAN  012/015-012/010-010/010
VI. Geomagnetic Activity Probabilities 30 DEC to 01 JAN
A. Middle Latitudes
Active20%20%15%
Minor storm10%10%05%
Major-severe storm05%05%01%
B. High Latitudes
Active45%45%35%
Minor storm25%25%20%
Major-severe storm10%10%05%

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