Viewing archive of Thursday, 23 April 1998

Solar activity report

Report of Solar-Geophysical Activity 1998 Apr 23 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 113 Issued at 2200Z on 23 APR 1998

IA. Analysis of Solar Active Regions and Activity from 22-2100Z to 23-2100Z

SOLAR ACTIVITY WAS HIGH. AN OPTICALLY UNCORRELATED X1 X-RAY BURST WAS DETECTED AT 23/0555Z. THIS ACTIVITY WAS ASSOCIATED WITH A LARGE CORONAL MASS EJECTED OFF THE SE-NE LIMB NOTED BY SPACE-BASED SENSORS. FURTHER ANALYSIS INDICATED THE FOOT POINTS OF THE EJECTION APPEARED TO BE LOCATED NEAR RETURNING REGIONS 8190 (S21,L144) AND 8196 (N18,L144). BOTH REGIONS ARE LESS THAN A DAY BEHIND THE EAST LIMB. THE X-RAY BURST WAS ACCOMPANIED BY A 10.7CM RADIO BURST OF 430 SFU, MAKING IT A TENFLARE, AND A TYPE IV SWEEP. POST FLARE LOOPS WERE OBSERVED AS WELL. NEW SWO REGION 8209 (S22W06), A SMALL AXX GROUP, WAS NUMBERED TODAY.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE LOW TO MODERATE. AN INCREASE IN ACTIVITY IS EXPECTED WITH THE RETURN OF REGION 8190, ESPECIALLY IN LIGHT OF TODAY'S ACTIVITY. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 22/2100Z TO 23/2100Z: THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. A SHOCK WAS NOTED ON ALL INSTRUMENTS AT ABOUT 23/1800Z, INDICATED BY AN INCREASE IN SOLAR WIND DENSITY AND SPEED, AN INCREASE IN PARTICLES DETECTED ON ACE AND GOES, AND A SMALL IMPULSE NOTED EARTH-BASED AND GEOSYNCHRONOUS MAGNETOMETERS. THE GREATER THAN 10 MEV PROTON EVENT IS STILL IN PROGRESS. THE EVENT CONTINUES TO DIMINISH AND IS CURRENTLY AT 30 PFU.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE MOSTLY UNSETTLED FOR THE NEXT 24 HOURS AT MID LATITUDES AND UNSETTLED TO ACTIVE FOR THE NEXT 48 HOURS AT HIGH LATITUDES. THEREAFTER, THE FIELD IS EXPECTED TO BE QUIET TO UNSETTLED.
III. Event Probabilities 24 APR to 26 APR
Class M 15%15%15%
Class X 10%10%10%
Proton05%05%05%
PCAFIN PROGRESS
IV. Penticton 10.7 cm Flux
  Observed       23 APR 090
  Predicted    24 APR-26 APR  092/094/094
  90 Day Mean        23 APR 104
V. Geomagnetic A Indices
OBSERVED AFR/AP 22 APR  005/006
ESTIMATED AFR/AP 23 APR  009/015
PREDICTED AFR/AP 24 APR-26 APR  015/020-010/015-010/012
VI. Geomagnetic Activity Probabilities 24 APR to 26 APR
A. Middle Latitudes
Active20%15%10%
Minor storm 10%05%05%
Major-severe storm 05%05%05%
B. High Latitudes
Active20%15%10%
Minor storm 15%10%10%
Major-severe storm 05%05%05%

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