FVXX21 KWBC 211800 VOLCANIC ASH ADVISORY ISSUED 1750 UTC 21 JUL 2000 BY THE WASHINGTON VAAC . TUNGURAHUA 00-852 ECUADOR 0128S 7826W . BACKGROUND: TUNGURAHUA ECUADOR (1502-08) SUMMIT HEIGHT 16480 FT (5023 M) . SOURCES OF INFORMATION: GOES-8 VISIBLE AND INFRARED AND MULTISPECTRAL IMAGERY. WIND FORECAST FROM THE AVIATION MODEL. SIGMET FROM THE GUAYAQUIL METEOROLOGICAL WATCH OFFICE. . ERUPTION DETAILS: GASES WITH OCCASIONAL ASH EMISSIONS. . DETAILS OF ASH: A SIGMET FROM GUAYAQUIL MWO NOTES THAT AT 1655 UTC ONE PILOT OBSERVED ASH UP TO FL240 AND ANOTHER OBSERVED ASH TO FL220. SATELLITE IMAGERY THROUGH 21/1715 UTC SHOWS LOW AND MID LEVEL CLOUDINESS IN THE VICINITY OF THE VOLCANO MAKING IT DIFFICULT TO DETECT ASH. . TRAJECTORY: UPPER AIR PATTERNS SUGGEST THAT ANY ASH BETWEEN THE SUMMIT AND FL240 WOULD MOVE TO THE WEST AT 10 TO 15 KTS. . OUTLOOK: SEE SIGMETS. . THE NEXT MESSAGE WILL BE ISSUED BY 22/0000 UTC. . REAL TIME SATELLITE IMAGERY ALONG WITH THIS AND OTHER VOLCANIC ASH ADVISORIES 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/) . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . NNNN