Viewing archive of Tuesday, 18 August 1998

Solar activity report

Report of Solar-Geophysical Activity 1998 Aug 18 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 230 Issued at 2200Z on 18 AUG 1998

IA. Analysis of Solar Active Regions and Activity from 17-2100Z to 18-2100Z

SOLAR ACTIVITY HAS BEEN HIGH. TWO X LEVEL (1.2 AT 17/2120UT AND 2.8 AT 18/0818UT)AND ONE M LEVEL (1.5 AT 18/0414UT) X-RAY EVENTS HAVE OCCURRED IN THE LAST 24 HOURS. THEY ARE BEING ASSOCIATED WITH REGION 8307 (N30E77) WHICH IS IN THE PROCESS OF CROSSING THE LIMB. OPTICAL AND X-RAY SENSORS HAVE SHOWN CORONAL LOOPS AND RAIN AS WELL AS ACTIVE SURGES AND BRIGHTENINGS. A SINGLE SPOT HAS COME OVER THE LIMB AT TIME OF ISSUE, BUT OF UNKNOWN TYPE. SUB-FAINT FLARES HAVE OCCURRED IN REGIONS 8297 (N32W80) AND 8299 (N16W69). A TYPE IV AND 10CM BURST WERE ASSOCIATED WITH THE X2.8 FLARE WHICH OCCURRED AT 0818UT. NO PARTICLE, PCA, OR GLE EVENTS HAVE TAKEN PLACE, AND THEY ARE NOT EXPECTED TO OCCUR.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE MODERATE TO HIGH. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 17/2100Z TO 18/2100Z: THE GEOMAGNETIC FIELD HAS BEEN QUIET. A CORONAL HOLE WHICH EXTENDS FROM THE NORTHERN POLE TO ALMOST N30 IS BELIEVED TO BE MOVING ACROSS THE CENTRAL MERIDIAN AND INTO A GEOEFFECTIVE POSITION. THREE DSFS OCCURRED IN THE LAST 24 HOURS. THE SIZES AND LOCATIONS WERE 9 DEG AT S30E22 ENDING AT 17/2332, 15 DEG AT N44W38 ENDING AT 17/2332, AND 10 DEG AT S51E16 ENDING AT 18/1150. THESE COMBINED WITH AN EXPECTED HIGH SPEED STREAM ARE CAUSE FOR EXPECTING HIGHER GEOMAGNETIC ACTIVITY IN THE NEXT 3 DAYS.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE UNSETTLED TO ACTIVE WITH ISOLATED MINOR STORM CONDITIONS AT HIGHER LATITUDES NEAR THE END OF THE DAY AND LATER IN THE PERIOD.
III. Event Probabilities 19 AUG to 21 AUG
Class M75%75%75%
Class X25%30%30%
Proton10%10%15%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       18 AUG 133
  Predicted   19 AUG-21 AUG  140/140/145
  90 Day Mean        18 AUG 114
V. Geomagnetic A Indices
OBSERVED AFR/AP 17 AUG  001/005
ESTIMATED AFR/AP 18 AUG  005/010
PREDICTED AFR/AP 19 AUG-21 AUG  010/015-015/020-020/020
VI. Geomagnetic Activity Probabilities 19 AUG to 21 AUG
A. Middle Latitudes
Active10%20%20%
Minor storm05%10%10%
Major-severe storm01%05%05%
B. High Latitudes
Active15%25%25%
Minor storm05%10%15%
Major-severe storm01%05%05%

<< 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!

100%

Latest alerts

Get instant alerts!

Space weather facts

Last X-flare:2017/09/10X8.2
Last M-flare:2017/10/20M1.0
Last geomagnetic storm:2019/09/28Kp5 (G1)
Number of spotless days in 2019:216
Current stretch spotless days:19

This day in history*

Solar flares
12000M3.0
22001M2.5
32003M2.4
42011M1.3
52001M1.3
ApG
1200157G4
2200349G2
3199823G1
4200620
5199920G1
*since 1994

Social networks