FVXX20 KWBC 121435 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 1435 UTC 12 SEPTEMBER 1999 BY THE WASHINGTON VAAC . GUAGUA PICHINCHA 99-009 ECUADOR 0.17S 78.60W . BACKGROUND: GUAGUA PICHINCHA (1502-02) SUMMIT HEIGHT 15,695FT (4784 M) . SOURCES OF INFORMATION: SIGMET FROM GUAYAQUIL METEOROLOGICAL WATCH OFFICE...INSTITUTO GEOFISICO ESCUELA POLITECNICA NACIONAL...00 UTC AVIATION MODEL RUN ERUPTION DETAILS: ERUPTION AT APPROXIMATELY 12/1127 UTC. . DETAILS OF ASH CLOUD: A SIGMET FROM GUAYAGUIL SUGGESTED AN ERUPTION OF GUAGUA PICHINCHA. THE GEOPHYSICAL INSTITUTE IN QUITO CONFIRMED THAT AN ERUPTION OCCURRED AT 1127 UTC. THE ERUPTION WAS OF SHORT DURATION LASTING ONLY 10 - 15 MINUTES AND SENT A COLUMN OF ASH TO APPROXIMATELY FL200. THE INSTITUTE FURTHER REPORTED THAT SUCH PHREATIC EXPLOSIONS HAVE BEEN OCCURRING FOR THE LAST COUPLE OF WEEKS. PREVIOUS ERUPTIONS HAVE RESULTED IN ASHFALL 80 TO 90 KM DOWNWIND. NO ASH COULD BE DISCERNED IN SATELLITE DATA THROUGH 1215 UTC DUE TO MID AND HIGH LEVEL CLOUDS. THE VOLCANO WAS QUIET AT 1400 UTC. . TRAJECTORY: TOWARD THE NORTHWEST AT 20 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. . THE NEXT MESSAGE WILL BE ISSUED AT 12/2030 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . NNNN