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 UTCPrepared 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 1998IA. 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 M | 70% | 70% | 70% |
| Class X | 30% | 30% | 30% |
| Proton | 15% | 20% | 20% |
| PCAF | GREEN | ||
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 | |||
|---|---|---|---|
| Active | 30% | 30% | 30% |
| Minor storm | 15% | 15% | 15% |
| Major-severe storm | 05% | 05% | 05% |
| B. High Latitudes | |||
|---|---|---|---|
| Active | 30% | 30% | 30% |
| Minor storm | 15% | 15% | 15% |
| Major-severe storm | 05% | 05% | 05% |
All times in UTC
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