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

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 355 Issued at 2200Z on 21 DEC 1998

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

SOLAR ACTIVITY WAS LOW. THE LARGEST EVENT OF THE PERIOD WAS AN OPTICALLY UNCORRELATED C5 FLARE AT 21/0429Z. REGION 8416 (N19E59) PRODUCED A C2/SF AT 21/1334Z. THIS REGION IS A SMALL E CLASS GROUP, POSSIBLY WITH MIXED POLARITIES. REGION 8415 (N20E24) EXHIBITED CONTINUED SLOW DECAY BUT RETAINED ITS BETA GAMMA MAGNETIC CLASSIFICATION. THIS REGION PRODUCED A C1/SF AT 21/1941Z. THE LARGE FILAMENT IN SPOTLESS PLAGE REGION 8414 (N26W10) WAS GENERALLY QUIET BUT SHOWED SLOW DENSIFICATION DURING THE PERIOD.
IB. Solar Activity Forecast
SOLAR ACTIVITY SHOULD REMAIN AT PREDOMINANTLY LOW LEVELS. REGION 8415 RETAINS THE CAPABILITY OF PRODUCING AN ISOLATED M-CLASS EVENT, BUT THAT POSSIBILITY IS WANING WITH THE DECAY IN THE REGION. REGION 8414 MAY PRODUCE A LONG DURATION X-RAY EVENT SHOULD THE LARGE FILAMENT ERUPT. SHOULD THIS OCCUR, A LARGE CORONAL MASS EJECTION WOULD LIKELY RESULT.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET. AT THIS TIME, THE EXPECTED SHOCK FROM THE HALO CORONAL MASS EJECTION ON 18 DEC HAS NOT ARRIVED.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD SHOULD BECOME DISTURBED ON 22 DEC. GENERALLY UNSETTLED TO ACTIVE CONDITIONS ARE EXPECTED ON THAT DAY. PERIODS OF MINOR AND POSSIBLY MAJOR STORMING ARE POSSIBLE SHOULD THAT DISTURBANCE ARRIVE AS EXPECTED. QUIET TO UNSETTLED GEOMAGNETIC CONDITIONS ARE FORECAST FOR 23-24 DEC.
III. Event Probabilities 22 DEC to 24 DEC
Class M40%35%30%
Class X05%05%05%
Proton05%05%05%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       21 DEC 135
  Predicted   22 DEC-24 DEC  132/135/138
  90 Day Mean        21 DEC 133
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 DEC  009/011
ESTIMATED AFR/AP 21 DEC  005/010
PREDICTED AFR/AP 22 DEC-24 DEC  025/018-012/009-008/009
VI. Geomagnetic Activity Probabilities 22 DEC to 24 DEC
A. Middle Latitudes
Active25%20%10%
Minor storm20%10%05%
Major-severe storm20%05%01%
B. High Latitudes
Active25%20%15%
Minor storm25%10%05%
Major-severe storm30%05%01%

<< 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!

23%
Support SpaceWeatherLive with our merchandise
Check out our merchandise

Latest alerts

Get instant alerts!

Space weather facts

Last X-flare2024/03/23X1.1
Last M-flare2024/03/28M7.0
Last geomagnetic storm2024/03/25Kp5 (G1)
Spotless days
Last spotless day2022/06/08
Monthly mean Sunspot Number
February 2024124.7 +1.7

This day in history*

Solar flares
12024M7.0
22001M6.17
32000M4.46
42022M4.0
52014M3.79
ApG
1200144G2
2200327G2
3199721G2
4201727G1
5200421G1
*since 1994

Social networks