FVXX20 KWBC 100900 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 0900 UTC 10 NOV 1999 BY THE WASHINGTON VAAC . GUAGUA PICHINCHA 99-078 ECUADOR 0.17S 78.60W . BACKGROUND: GUAGUA PICHINCHA ECUADOR (1502-02) SUMMIT HEIGHT 15695 FT (4784 M) . SOURCES OF INFORMATION: GEOPHYSICAL INSTITUTE IN QUITO...INFRARED AND MULTISPECTRAL GOES-8 SATELLITE IMAGERY...00 UTC AVIATION MODEL WINDS...03 UTC SURFACE REPORT FROM QUITO/MARISCAL . ERUPTION DETAILS: REPORTED EXPLOSIVE ERUPTION AT 10/0025 UTC. . DETAILS OF ASH CLOUD: NO ASH IS VISIBLE IN SATELLITE IMAGERY THROUGH 10/0815 UTC. HOWEVER THERE ARE SOME LOW LEVEL METEOROLOGICAL CLOUDS IN THE AREA WHICH MIGHT BE OBSCURING ASH. THE O3Z METAR FROM SEQU WHICH IS QUITO/MARISCAL REPORTED VOLCANIC ASH OVER THE STATION. EARLIER TODAY THE GEOPHYSICAL INSTITUTE REPORTED ASH FALLING IN NORTHERN QUITO. IT IS VERY DIFFICULT TO ASSIGN A HEIGHT TO THE ASH. BASED ON ASHFALL LOCATIONS AND UPPER AIR PATTERNS THE OBSERVED ASH WAS PREVIOUSLY ESTIMATED TO BE UP TO FL250. . TRAJECTORY: UPPER AIR PATTERNS SUGGEST THAT ANY ASH BETWEEN FL320 AND FL220 WILL MOVE TO THE EAST OR EAST NORTHEAST AT ABOUT 10 KNOTS. ASH BETWEEN FL200 AND FL160 WILL MOVE TOWARD THE SOUTHEAST AT LESS THAN 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 http://www.ssd.noaa.gov/VAAC/washington.html (all lower case except /VAAC/) . OUTLOOK: SEE SIGMETS . THE NEXT STATEMENT WILL BE ISSUED BY 10/1500 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . NNNN