FVXX21 KWBC 181900
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VOLCANIC ASH ADVISORY STATEMENT
ISSUED 1900 UTC 18 MAR 1999 BY THE WASHINGTON VAAC
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POPOCATEPETL 99-025    MEXICO  19.02N 98.62W 
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BACKGROUND:    POPOCATEPETL   MEXICO (1401-09)
               SUMMIT HEIGHT 17930 FT (5465 M)
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SOURCES OF INFORMATION: GOES-8 VISIBLE  INFRARED AND MULTISPECTRAL
IMAGERY.  MEXICO CITY UPPER AIR SOUNDING.            
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ERUPTION DETAILS: ERUPTION OCCURRED AROUND 18/1130 UTC     
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DETAILS OF ASH CLOUD: GOES 8 IMAGERY THROUGH 1815 UTC SHOWS THAT THE
ASH PLUME HAS BECOME VERY DIFUSE AND HARD TO DISTINGUISH FROM
METEOROLOGICAL CLOUDS.  THE PLUME WAS LAST CLEARLY VISIBLE IN THE
1615 UTC IMAGE NEAR 22.1N 93.4W.  BY FOLLOWING THE CLOUD MOTION
SIGNATURES AND USING EXTRAPOLATION THE POSITION OF THE ASH PLUME AT
1815 IS NEAR 22.8N 91.8W.
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TRAJECTORY: 1200 UTC MEXICO CITY SOUNDING SUGGESTS ASH BETWEEN FL350
AND FL400 WOULD MOVE TOWARD THE NORTHEAST AT ABOUT 65 KTS.
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THIS AND OTHER VOLCANIC ASH ADVISORY STATEMENTS OFTEN ACCOMPANIED BY
A MAP DEPICTING ASH LOCATION ARE AVAILABLE AT INTERNET URL ADDRESS
www.ssd.noaa.gov/VAAC/messages.html
(all lower case except /VAAC/)
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OUTLOOK: SEE SIGMETS AND VAFTAD.
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THE NEXT MESSAGE WILL BE ISSUED AT 19/0100 UTC.
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PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS.
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