FVXX20 KWBC 180445 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 0445 UTC 18 OCTOBER 1999 BY THE WASHINGTON VAAC . GUAGUA PICHINCHA 99-051 ECUADOR 0.17S 78.60W . BACKGROUND: GUAGUA PICHINCHA (1502-02) SUMMIT HEIGHT 15,695 FT (4784 M) . SOURCES OF INFORMATION:GEOPHYSICAL INSTITUTE IN QUITO...INFRARED AND MULTISPECTRAL GOES 8 SATELLITE IMAGERY...AVIATION 18 HOUR FORECAST FROM 17/1200 UTC MODEL RUN . ERUPTION DETAILS: EXPLOSIVE ERUPTION OCCURRED AT 18/0321 UTC. . DETAILS OF ASH CLOUD: THE GEOPHYSICAL INSTITUTE IN QUITO INDICATED THAT...BASED ON SEISMIC ACTIVITY...AN EXPLOSIVE ERUPTION OF GUAGUA PICHINCHA OCCURRED AT 0321 UTC. SATELLITE IMAGERY THROUGH 0415 UTC REVEALED A SMALL NARROW PLUME 10 KM (5 NMI) WIDE EXTENDING FROM 0.2S/78.6W TO 0.3S/78.7W. THIS PLUME WAS ESTIMATED TO BE AT FL320 BASED ON MODEL DATA TAKEN FROM THE 17/1200 UTC RUN. . TRAJECTORY: TOWARD THE SOUTHWEST AT 5 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 www.ssd.noaa.gov/VAAC/washington.html (all lower case except /VAAC/) . OUTLOOK: SEE SIGMETS AND VAFTAD. . THE NEXT MESSAGE WILL BE ISSUED AROUND 18/1045Z. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . NNNN