FVXX21 KWBC 241900 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 1900 UTC 24 DEC 1999 BY THE WASHINGTON VAAC . TUNGURAHUA 99-289 ECUADOR 1.47S 78.44W . BACKGROUND: TUNGURAHUA ECUADOR (1502-08) SUMMIT HEIGHT 16480 FT (5023 M) . SOURCES OF INFORMATION: GOES-8 VISIBLE INFRARED AND MULTISPECTRAL IMAGERY...GEOPHYSICAL INSTITUTE REPORT...1200 UTC AVIATION MODEL WIND FORECAST...SIGMET FROM GUAYAQUIL METEOROLOGICAL WATCH OFFICE . ERUPTION DETAILS: INTERMITTENT ASH AND STEAM EMISSIONS . DETAILS OF ASH: A SIGMET FROM GUAYAQUIL INDICATES THAT EARLIER TODAY THE GEOPHYSICAL INSTITUTE OBSERVED VOLCANIC ASH AT FL190. IN GENERAL OCCASIONAL SMALL EXPLOSIONS HAVE BEEN REPORTED BY THE GEOPHYSICAL INSTITUTE ON AN ALMOST DAILY BASIS AND THESE TYPICALLY PRODUCED ASH AND STEAM BETWEEN FL180 AND FL230. CURRENTLY NO ASH CAN BE SEEN IN SATELLITE IMAGERY THROUGH 24/1815 UTC POSSIBLY DUE TO THE WEATHER CLOUDS IN THE AREA. . TRAJECTORY: UPPER AIR PATTERNS SUGGEST THAT ANY ASH BETWEEN FL160 AND FL230 WOULD MOVE AT 10 KNOTS OR LESS. THE WIND IS LIGHT AND VARIABLE BUT ASH AT THESE LEVELS WOULD GENERALLY MOVE TOWARD THE WEST. . 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 25/0100 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . STREETT . NNNN