Viewing archive of Sunday, 20 December 1998

Solar activity report

Report of Solar-Geophysical Activity 1998 Dec 20 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 354 Issued at 2200Z on 20 DEC 1998

IA. Analysis of Solar Active Regions and Activity from 19-2100Z to 20-2100Z

SOLAR ACTIVITY WAS MODERATE. REGION 8415 (N20E38) PRODUCED AN M1/1N FLARE AT 20/0900Z THAT WAS ACCOMPANIED BY MINOR RADIO BURSTS. THIS REGION ALSO PRODUCED SEVERAL LOW TO MID C-CLASS EVENTS DURING THE PERIOD. MIXED MAGNETIC POLARITIES REMAINED IN THIS REGION BUT AREAL COVERAGE IN WHITE LIGHT DECREASED SLIGHTLY. A SMALL CLASS C SUNSPOT GROUP ROTATED ONTO THE DISK NEAR N18E67 AND WAS NUMBERED AS NEW REGION 8416. TWO LESSER REGIONS EMERGED ON THE DISK.
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD BECOME GENERALLY LOW FOR THE NEXT THREE DAYS. REGION 8415 IS CAPABLE OF PRODUCING ISOLATED M-CLASS EVENTS. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 19/2100Z TO 20/2100Z: THE GEOMAGNETIC FIELD WAS PREDOMINANTLY UNSETTLED. DURING THE PERIOD, SOLAR WIND VELOCITY INCREASED, DENSITY DECREASED, AND SEVERAL INTERVALS OF PROLONGED SOUTHWARD BZ WERE OBSERVED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS FORECAST TO BE QUIET TO UNSETTLED UNTIL THE LATTER HALF OF 21 DEC WHEN A DISTURBANCE IS EXPECTED TO BEGIN. GENERALLY UNSETTLED TO ACTIVE LEVELS ARE EXPECTED FROM THAT TIME THROUGH THE END OF 22 DEC. DURING THIS DISTURBANCE, PERIODS OF MINOR STORMING ARE POSSIBLE AT ALL LATITUDES WITH ISOLATED INTERVALS OF MAJOR STORMING POSSIBLE AT HIGH LATITUDES.
III. Event Probabilities 21 DEC to 23 DEC
Class M50%40%40%
Class X05%05%05%
Proton05%05%05%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       20 DEC 135
  Predicted   21 DEC-23 DEC  130/128/129
  90 Day Mean        20 DEC 133
V. Geomagnetic A Indices
OBSERVED AFR/AP 19 DEC  006/007
ESTIMATED AFR/AP 20 DEC  012/012
PREDICTED AFR/AP 21 DEC-23 DEC  018/020-025/025-012/009
VI. Geomagnetic Activity Probabilities 21 DEC to 23 DEC
A. Middle Latitudes
Active30%30%20%
Minor storm20%20%05%
Major-severe storm20%20%01%
B. High Latitudes
Active25%25%20%
Minor storm25%25%05%
Major-severe storm30%30%01%

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