Viewing archive of Monday, 20 April 1998

Solar activity report

Report of Solar-Geophysical Activity 1998 Apr 20 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 110 Issued at 2200Z on 20 APR 1998

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

SOLAR ACTIVITY BECAME MODERATE. A LONG DURATION M1 X-RAY EVENT AND TYPE II SWEEP OCCURRED AT 20/1021UT. THE LIKELY SOURCE FOR THE FLARE WAS BEHIND THE SW LIMB. SPACE-BASED SENSORS INDICATE STRONG EMISSIONS ON THE LIMB ALONG S25. A LARGE CME WAS ALSO OBSERVED OFF THE W-SW LIMB. FAINT POST FLARE LOOPS WERE ALSO EVIDENT. REGION 8205 (N21W40) CHANGED VERY LITTLE IN THE PAST 24 HOURS, AND MAINTAINS IT'S DSO BETA CONFIGURATION. THE REMAINING REGIONS HAVE BEEN QUIET.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO BE VERY LOW TO LOW. REGION 8205 HAS SMALL POTENTIAL TO PRODUCE A C-CLASS FLARE. FURTHER ACTIVITY ALONG THE SW LIMB IS POSSIBLE BUT UNLIKELY AS POSSIBLE SOURCE REGION ROTATES FURTHER BEHIND THE LIMB. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 19/2100Z TO 20/2100Z: THE GEOMAGNETIC FIELD WAS QUIET TO ACTIVE. A GREATER THAN 10 MEV PROTON EVENT BEGAN AT 20/1130Z, PASSED THE 10 PFU THRESHOLD AT 20/1400Z, AND IS CURRENTLY STEADY AT A MAXIMUM OF 330 PFU. THE GREATER THAN 100 MEV PROTON FLUX IS AT 2.3 PFU AND STILL RISING SLOWLY. POLAR CAP ABSORPTION IS CURRENTLY AT A MAXIMUM OF 6.4 DB.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO CONTINUE AT QUIET TO ACTIVE LEVELS. MOST OF THE MATERIAL FROM THIS MORNING'S ACTIVITY APPEARS WESTWARD BOUND, THUS, NO SIGNIFICANT IMPACT IS EXPECTED ON THE GEOMAGNETIC FIELD. THE 10 AND 100 MEV PROTON EVENTS ARE EXPECTED TO CONTINUE THROUGH TOMORROW.
III. Event Probabilities 21 APR to 23 APR
Class M 10%05%05%
Class X 01%01%01%
Proton10%05%01%
PCAFIN PROGRESS
IV. Penticton 10.7 cm Flux
  Observed       20 APR 098
  Predicted    21 APR-23 APR  096/094/092
  90 Day Mean        20 APR 104
V. Geomagnetic A Indices
OBSERVED AFR/AP 19 APR  002/004
ESTIMATED AFR/AP 20 APR  010/012
PREDICTED AFR/AP 21 APR-23 APR  010/010-012/012-010/012
VI. Geomagnetic Activity Probabilities 21 APR to 23 APR
A. Middle Latitudes
Active15%25%25%
Minor storm 05%10%10%
Major-severe storm 01%05%05%
B. High Latitudes
Active20%30%30%
Minor storm 05%15%10%
Major-severe storm 05%11%11%

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