FVXX20 KWBC 111640 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 1640 UTC 11 DEC 1999 BY THE WASHINGTON VAAC . GUAGUA PICHINCHA 99-150 ECUADOR 0.17S 78.60W . BACKGROUND: GUAGUA PICHINCHA ECUADOR (1502-02) SUMMIT HEIGHT 15695 FT (4784 M) . SOURCES OF INFORMATION: THE GEOPHYSICAL INSTITUTE IN ECUADOR...QUITO SURFACE OBSERVATION...GOES-8 VISIBLE...INFRARED AND MULTISPECTRAL IMAGERY... U.S. NUMERICAL MODEL WIND FORECAST. . ERUPTION DETAILS: EXPLOSION AT 11/0734 UTC. . DETAILS OF ASH CLOUD: ASH IS NO LONGER VISIBLE IN THE LATEST SATELLITE IMAGERY THROUGH 1545 UTC. . TRAJECTORY: UPPER AIR PATTERN AND NUMERICAL GUIDANCE SUGGEST ANY REMAINING ASH AT FL250 WOULD MOVE TOWARD THE WEST AT 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 AND VAFTAD. . 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 A WATCH STATEMENT AT 12/1700 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . BROWN . NNNN