FVXX20 KWBC 210700
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VOLCANIC ASH ADVISORY STATEMENT
ISSUED 0700 UTC 21 JULY 1999 BY THE WASHINGTON VAAC 
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SOUFRIERE HILLS 99-183    WEST INDIES 16.7N 62.2W
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BACKGROUND:    SOUFRIERE HILLS MONTSERRAT (1600-05)
               SUMMIT HEIGHT 3000 FT (915M)
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SOURCES OF INFORMATION: GOES-8 INFRARED AND MULTISPECTRAL IMAGERY
THROUGH 21/0545 UTC.  MONTSERRAT VOLCANO OBSERVATORY. 21/0000 UTC
GUADELOUPE RADIOSONDE.  VAFTAD

ERUPTION DETAILS:  ERUPTION OCCURRED AT ABOUT 20/0910 UTC.
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DETAILS OF ASH CLOUD: THE 21/0545 UTC SATELLITE IMAGE SHOWS THIN ASH
APPROXIMATELY BOUNDED BY 17.4N66.5W 16.9N66.6W 16.9N65.4W 18.6N63.4W
18.9N63.8W 17.8N65.3W AND 17.4N66.5W AND PROBABLY BELOW FL140. AT 0545
UTC  THIS ASH APPEARED TO BE WITHIN ABOUT 40 KM (22 NMI) OF PUERTO
RICO.  HIGHER LEVEL ASH PREVIOUSLY TRACKED TO THE NORTHEAST OF
MONTSERRAT IS NOW TOO DISPERSED TO BE OBSERVED IN SATELLITE IMAGERY
BUT MIGHT STILL BE PRESENT.  THE VAFTAD SUGGESTS THAT THIS POSSIBLE
HIGH LEVEL ASH MIGHT EXTEND AS FAR NORTH AS 24N AND AS FAR EAST AS
58E.
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TRAJECTORY: ASH BELOW FL140 IS OBSERVED MOVING TO THE WEST NORTHWEST
AT 15 KNOTS.  UPPER AIR PATTERNS SUGGEST THAT POSSIBLE HIGHER ASH SUCH
AS ANY ASH BETWEEN FL250 AND FL400 WOULD MOVE TO THE NORTHEAST AT LESS
THAN 25 KNOTS.
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REAL TIME SATELLITE IMAGERY ALONG WITH 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/washington.html
(all lower case except /VAAC/)
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OUTLOOK:  SEE LATEST SIGMETS AND VAFTAD.
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THE NEXT MESSAGE WILL BE ISSUED BY 21/1300 UTC.
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PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS.
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NNNN
"Attached Graphic Map Depicting Ash" 

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