Viewing archive of Sunday, 18 April 1999

Solar activity report

Report of Solar-Geophysical Activity 1999 Apr 18 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 108 Issued at 2200Z on 18 APR 1999

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

SOLAR ACTIVITY REMAINED AT VERY LOW LEVELS. ISOLATED B-CLASS X-RAY FLARES OCCURRED, TWO OF WHICH WERE OPTICALLY TIED TO REGION 8514 (S33W69). THIS REGION SHOWED GRADUAL DECAY AS IT APPROACHED THE WEST LIMB. ALL THE REMAINING REGIONS WERE EITHER STABLE OR DECLINING SLOWLY. A 21-DEGREE FILAMENT, LAST SEEN CENTERED NEAR N19E03, DISAPPEARED EARLY IN THE PERIOD. A PARTIAL-HALO CME WAS OBSERVED AROUND 17/0600Z. NO NEW REGIONS WERE ASSIGNED.
IB. Solar Activity Forecast
SOLAR ACTIVITY IS EXPECTED TO REMAIN AT VERY LOW LEVELS. IIA. GEOPHYSICAL ACTIVITY SUMMARY FROM 17/2100Z TO 18/2100Z: THE GEOMAGNETIC FIELD WAS MOSTLY QUIET WITH BRIEF UNSETTLED INTERVALS AT ALL LATITUDES.
IIB. Geophysical Activity Forecast
THE GEOMAGNETIC FIELD IS EXPECTED TO BE AT QUIET TO UNSETTLED LEVELS DURING THE FIRST TWO DAYS, THEN INCREASE TO ACTIVE LEVELS ON THE THIRD DAY IN RESPONSE TO THE CME MENTIONED ABOVE.
III. Event Probabilities 19 APR to 21 APR
Class M10%10%10%
Class X01%01%01%
Proton01%01%01%
PCAFGREEN
IV. Penticton 10.7 cm Flux
  Observed       18 APR 113
  Predicted   19 APR-21 APR  110/110/110
  90 Day Mean        18 APR 134
V. Geomagnetic A Indices
OBSERVED AFR/AP 17 APR  030/047
ESTIMATED AFR/AP 18 APR  008/010
PREDICTED AFR/AP 19 APR-21 APR  005/008-010/012-020/015
VI. Geomagnetic Activity Probabilities 19 APR to 21 APR
A. Middle Latitudes
Active10%15%50%
Minor storm05%05%10%
Major-severe storm01%01%05%
B. High Latitudes
Active15%20%50%
Minor storm10%10%20%
Major-severe storm01%01%05%

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