Viewing archive of Wednesday, 23 December 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 Dec 23 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 357 Issued at 2200Z on 23 DEC 1998

IA. Analysis of Solar Active Regions and Activity from 22-2100Z to 23-2100Z

SOLAR ACTIVITY WAS MODERATE. A SERIES OF OPTICALLY UNCORRELATED X-RAY EVENTS OCCURRED THROUGH THE PERIOD. THE FIRST WAS A C6 AT 22/2351Z. A LONG DURATION M2 OCCURRED AT 23/0659Z WITH AN ASSOCIATED TYPE II AND TYPE IV RADIO SWEEP. THE TYPE II SHOCK SPEED WAS 850 KM/S. THIS EVENT WAS FOLLOWED SOON AFTER BY AN M1 AT 23/0816Z. POST FLARE LOOPS OBSERVED AT N24E89 SUGGEST NEW REGION NUMBERED TODAY AS 8421 (N29E83) WAS THE LIKELY SOURCE REGION FOR ALL THESE EVENTS. REGION 8421 APPEARS TO BE A LARGE COMPLEX AREA WHICH HAS PRODUCED STRONG SURGING SINCE BECOMING VISIBLE ON THE LIMB. OTHER NEW REGIONS NUMBERED TODAY WERE REGION 8419 (N27E25) AND REGION 8420 (N18E64). TWO DISAPPEARING FILAMENTS WERE REPORTED, ONE BETWEEN 22/2320Z AND 23/1713Z AT N23W23 WHICH WAS 10 DEGREES LONG AND THE OTHER BETWEEN 23/1753-1812Z AT N16E37 WHICH WAS 5 DEGREES LONG.
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD BE LOW TO MODERATE. SEVERAL OF THE REGIONS ON THE DISK ARE CAPABLE OF PRODUCING OCCASIONAL M-CLASS FLARES ESPECIALLY REGION 8421.
IIA. Geophysical Activity Summary 22-2100Z to 23-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE QUIET TO SLIGHTLY UNSETTLED THROUGH THE FORECAST PERIOD.
III. Event Probabilities 24 DEC to 26 DEC
Class M40%40%40%
Class X05%05%05%
Proton05%05%05%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       23 DEC 140
  Predicted   24 DEC-26 DEC  145/148/150
  90 Day Mean        23 DEC 133
V. Geomagnetic A Indices
OBSERVED AFR/AP 22 DEC  002/005
ESTIMATED AFR/AP 23 DEC  008/012
PREDICTED AFR/AP 24 DEC-26 DEC  005/009-005/009-005/009
VI. Geomagnetic Activity Probabilities 24 DEC to 26 DEC
A. Middle Latitudes
Active10%10%10%
Minor storm05%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Active15%15%15%
Minor storm05%05%05%
Major-severe storm05%05%05%

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