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

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 111 Issued at 2200Z on 21 APR 1998

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

SOLAR ACTIVITY WAS VERY LOW. THE ONLY ACTIVITY OF NOTE WAS AN ERUPTIVE PROMINENCE THAT OCCURRED ON THE WEST LIMB NEAR N30. NO OTHER ACTIVITY WAS NOTED WITH THIS ERUPTION. REGION 8205 (N21W53) DECAYED SLIGHTLY IN WHITE LIGHT AREA BUT IS STILL EXHIBITING OCCASIONAL PLAGE FLUCTUATIONS AND SURGING. THE REMAINING REGIONS HAVE BEEN QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE VERY LOW TO LOW. REGION 8205 HAS POTENTIAL TO PRODUCE AN ISOLATED C-CLASS FLARE. STILL A SLIGHT CHANCE FOR FURTHER ACTIVITY NEAR THE SW LIMB - THE SOURCE OF YESTERDAY'S M1 X-RAY FLARE; HOWEVER, THE LIKELY SOURCE REGION HAS PROBABLY ROTATED ENOUGH TO ELIMINATE CONCERN.
IIA. Geophysical Activity Summary 20-2100Z to 21-2100Z
THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. THE GREATER THAN 10 MEV PROTON EVENT THAT BEGAN AT 20/1130Z IS STILL IN PROGRESS. A MAXIMUM VALUE OF 1700 PFU WAS REACHED AT 21/1205. THE EVENT APPEARS TO BE IN DECLINE NOW WITH A CURRENT VALUE OF 640 PFU. THE GREATER THAN 100 MEV EVENT PEAKED AT 7.4 PFU AT 21/1255Z AND IS CURRENTLY AT 2.5 PFU.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO CONTINUE AT QUIET TO UNSETTLED LEVELS. AN EXTENSION OF THE SOUTHERN CORONAL HOLE WILL MOVE INTO FAVORABLE POSITION FOR GEOEFFECTIVNESS ON DAY TWO AND THREE. EXPECT OCCASIONAL ACTIVE PERIODS DURING THIS PERIOD. THE PROTON EVENT IN PROGRESS IS EXPECTED TO LAST THROUGH TOMORROW.
III. Event Probabilities 22 APR to 24 APR
Class M05%05%05%
Class X01%01%01%
Proton05%05%01%
PCAFIN PROGRESS
IV. Penticton 10.7 cm Flux
  Observed       21 APR 92
  Predicted   22 APR-24 APR  092/090/090
  90 Day Mean        21 APR 104
V. Geomagnetic A Indices
OBSERVED AFR/AP 20 APR  009/010
ESTIMATED AFR/AP 21 APR  007/010
PREDICTED AFR/AP 22 APR-24 APR  012/010-012/015-012/020
VI. Geomagnetic Activity Probabilities 22 APR to 24 APR
A. Middle Latitudes
Active15%30%30%
Minor storm05%05%05%
Major-severe storm01%01%01%
B. High Latitudes
Active20%40%45%
Minor storm10%10%10%
Major-severe storm01%06%06%

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-flare2024/12/25M4.9
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
22024M4.9
32024M2.8
41998M1.83
52001M1.76
DstG
11988-85
21998-57
31978-57G2
42014-49
52002-39
*since 1994

Social networks