FVXX21 KWBC 160600 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 0600 UTC 16 DEC 1999 BY THE WASHINGTON VAAC . TUNGURAHUA 99-253 ECUADOR 1.47S 78.44W . BACKGROUND: TUNGURAHUA ECUADOR (1502-08) SUMMIT HEIGHT 16480 FT (5023 M) . SOURCES OF INFORMATION: GOES-8 INFRARED AND MULTISPECTRAL IMAGERY...1800 UTC AVIATION MODEL WIND FORECAST...GEOPHYSICAL INSTITUTE REPORT AND UPPER AIR DATA. . ERUPTION DETAILS: STEAM EMISSIONS WITH OCCASIONAL PULSES OF ASH. . DETAILS OF ASH: NO ASH CAN BE SEEN IN SATELLITE IMAGERY THROUGH 0515 UTC. THE FAINT ASH PLUME AT FL240 OBSERVED EARLIER EXTENDING TOWARD THE SOUTHWEST IS NOW TOO DIFFUSE TO SEE IN IMAGERY. . TRAJECTORY: UPPER AIR PATTERNS SUGGEST THAT ANY ASH AT ABOUT FL240 WOULD MOVE TO THE SOUTHWEST AT ABOUT 15 KNOTS. . 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/) . OUTLOOK: SEE SIGMETS . EFFECTIVE JANUARY 3 2000 AT 0000 UTC... ALL REFERENCES TO LATITUDE AND LONGITUDE IN VOLCANIC ASH ADVISORY STATEMENTS WILL BE IN DEGREES AND MINUTES OF A DEGREE. EXAMPLE: 16.70N 62.20W WILL BE 1642N6212W . THE NEXT STATEMENT WILL BE ISSUED BY 16/1200 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . STREETT . NNNN