Viewing archive of Sunday, 20 September 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 Sep 20 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 263 Issued at 2200Z on 20 SEP 1998

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

SOLAR ACTIVITY WAS MODERATE. REGION 8340 (N19E38) PRODUCED AN M1 FLARE AT 19/0251Z. A STRONG TYPE IV SWEEP AND 340 SFU TENFLARE ACCOMPANIED THIS FLARE. REGION 8336 (S29W02) PRODUCED A C1/SF AT 19/0949Z AND IS SHOWING SIGNS OF FURTHER DEVELOPMENT. REGION 8342 (N18E25) WAS ACTIVE THROUGHOUT THE PERIOD EXHIBITING FREQUENT PLAGE FLUCTUATIONS WHILE PRODUCING SEVERAL SUBFLARES. REMAINING REGIONS WERE QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE PREDOMINANTLY LOW. REGIONS 8336 AND 8340 ARE BOTH CAPABLE OF PRODUCING C-CLASS ACTIVITY AND HAVE AN OUTSIDE CHANCE OF AN M-CLASS FLARE. REGION 8342 IS STILL DEVELOPING AND MAY SOON BE CAPABLE OF C-CLASS ACTIVITY.
IIA. Geophysical Activity Summary 19-2100Z to 20-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE QUIET TO UNSETTLED WITH OCCASIONAL ACTIVE PERIODS AT MOSTLY HIGH LATITUDES.
III. Event Probabilities 21 SEP to 23 SEP
Class M10%10%10%
Class X01%01%01%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       20 SEP 132
  Predicted   21 SEP-23 SEP  135/135/140
  90 Day Mean        20 SEP 128
V. Geomagnetic A Indices
OBSERVED AFR/AP 19 SEP  008/012
ESTIMATED AFR/AP 20 SEP  009/010
PREDICTED AFR/AP 21 SEP-23 SEP  015/015-015/015-015/015
VI. Geomagnetic Activity Probabilities 21 SEP to 23 SEP
A. Middle Latitudes
Active30%30%30%
Minor storm10%10%10%
Major-severe storm01%01%01%
B. High Latitudes
Active40%40%40%
Minor storm15%15%15%
Major-severe storm05%05%05%

All times in UTC

<< Go to daily overview page

Latest news

Support SpaceWeatherLive.com!

A lot of people come to SpaceWeatherLive to follow the Sun's activity or if there is aurora to be seen, but with more traffic comes higher server costs. Consider a donation if you enjoy SpaceWeatherLive so we can keep the website online!

SpaceWeatherLive Pro
Support SpaceWeatherLive with our merchandise
Check out our merchandise

Latest alerts

Get instant alerts!

Space weather facts

Last X-flare2024/12/08X2.2
Last M-flare2024/12/24M1.0
Last geomagnetic storm2024/12/17Kp5+ (G1)
Spotless days
Last spotless day2022/06/08
Monthly mean Sunspot Number
November 2024152.5 -13.9
December 2024115.2 -37.3
Last 30 days120.1 -38.2

This day in history*

Solar flares
12011M5.77
21998M1.83
32001M1.76
42001M1.41
52011M1.22
DstG
11988-85
21998-57
31978-57G2
42014-49
52002-39
*since 1994

Social networks