Viewing archive of Friday, 21 August 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 Aug 21 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 233 Issued at 2200Z on 21 AUG 1998

IA. Analysis of Solar Active Regions and Activity from 20-2100Z to 21-2100Z

SOLAR ACTIVITY BECAME LOW. REGION 8307 (N31E47) PRODUCED A C1/SF FLARE AT 21/1620Z. SEVERAL OTHER SMALL TO MID C-CLASS EVENTS OCCURRED BUT WERE NOT OPTICALLY CORRELATED WITH A SPECIFIC REGION. CONFLICTING DATA HAVE BEEN RECEIVED REGARDING THE GROWTH OR DECAY OF REGION 8307. TIGHT MAGNETIC GRADIENTS REMAINED IN THIS REGION BUT BY TECHNICAL DEFINITION, THE DELTA CONFIGURATION FADED. VECTOR MAGNETOGRAPH DATA ON REGION 8307 FROM 20 AUG DID NOT SHOW LARGE AREAS OF HIGH SHEAR.
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD BE GENERALLY LOW TO MODERATE. REGION 8307 HAS SHOWN ITS CAPABILITY OF PRODUCING X-CLASS EVENTS AND MORE REMAIN POSSIBLE. HOWEVER, RECENT TRENDS INDICATE A LESSENING IN THE RATE OF FLARE PRODUCTION FROM THIS REGION.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. SOLAR WIND DATA SHOW A LOW VELOCITY FLOW IN THE EARTH'S VICINITY WITH PREDOMINANTLY NORTHWARD BZ.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD BE QUIET TO SLIGHTLY ACTIVE FOR THE NEXT THREE DAYS. AN EQUATORWARD EXTENSION OF THE NORTHERN POLAR CORONAL HOLE IS EXPECTED TO BEGIN TO DISTURB THE GEOMAGNETIC FIELD DURING THE PERIOD.
III. Event Probabilities 22 AUG to 24 AUG
Class M70%70%70%
Class X30%30%30%
Proton15%20%20%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       21 AUG 132
  Predicted   22 AUG-24 AUG  135/138/139
  90 Day Mean        21 AUG 115
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 AUG  014/018
ESTIMATED AFR/AP 21 AUG  005/008
PREDICTED AFR/AP 22 AUG-24 AUG  015/020-015/015-012/015
VI. Geomagnetic Activity Probabilities 22 AUG to 24 AUG
A. Middle Latitudes
Active30%30%30%
Minor storm15%15%15%
Major-severe storm05%05%05%
B. High Latitudes
Active30%30%30%
Minor storm15%15%15%
Major-severe storm05%05%05%

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