FVXX23 KWBC 212325
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VOLCANIC ASH ADVISORY STATEMENT
ISSUED 2325 UTC 21 NOV 1999 BY THE WASHINGTON VAAC
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MASAYA 99-001      NICARAGUA 11.98N 86.16W 
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BACKGROUND:    MASAYA NICARAGUA (1401-10)
               SUMMIT HEIGHT 2083 FT (635 M)
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SOURCES OF INFORMATION: GOES-8 VISIBLE...INFRARED...AND
MULTISPECTRAL SATELLITE IMAGERY...21/1200 UTC AVIATION MODEL DATA 
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ERUPTION DETAILS: POSSIBLE ASH AND STEAM EMISSIONS BEGINNING BETWEEN
1900 AND 2000 UTC...POSSIBLE EXPLOSION AROUND 2200 UTC.
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DETAILS OF ASH CLOUD: A VOLCANO WHICH HAS HAD A LONG HISTORY OF
BEING VERY ACTIVE MAY WELL HAVE AWAKENED AGAIN AS OF TODAY.
SATELLITE IMAGERY FROM GOES-8 STRONGLY SUGGESTS THAT THERE IS SOME
ACTIVITY AT OR VERY NEAR THE MASAYA VOLCANO SITE. THERE WAS SOME
WEAK SUGGESTION OF A PLUME OF POSSIBLE ASH OR SMOKE SEVERAL HOURS
AGO MOVING TO THE WEST-SOUTHWEST BUT THERE HAS BEEN NO OTHER
INFORMATION THAT WOULD INDICATE ANY ERUPTIONS OR ACTIVITY. SATELLITE
IMAGERY HOWEVER OVER THE TWO HOURS IS INDICATING A PERIODIC HOT SPOT
AND THE LAST VISIBLE IMAGES SUGGEST THAT SOME TYPE OF EXPLOSION MAY
HAVE OCCURRED AT AROUND 2200 UTC. AT 2215 UTC THERE IS A PLUME OF
POSSIBLE ASH SEEN AND IT IS ESTIMATED TO BE AT FL025. THIS MAKES THE
ACTIVITY NEAR-SUMMIT. THE PLUME EXTENDS 37 KM (20 NMI) TO THE WEST-SOUTHWEST OF THE SUMMIT. IT IS ABOUT 13 KM (7 NMI) WIDE.
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TRAJECTORY: ASH FROM THE SUMMIT TO FL025 IS MOVING WEST-SOUTHWEST AT
10 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  
http://www.ssd.noaa.gov/VAAC/washington.html
(all lower case except /VAAC/)
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OUTLOOK: SEE SIGMETS.
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THE NEXT STATEMENT WILL BE ISSUED BY 22/0530 UTC.
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PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS.
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ORRISON
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NNNN"Attached Graphic Map Depicting Ash" 

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