FVXX21 KWBC 151740 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 1740 UTC 15 DEC 1999 BY THE WASHINGTON VAAC . TUNGURAHUA 99-251 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...U.S. NUMERICAL MODEL WIND FORECASTS...GEOPHYSICAL INSTITUTE REPORT AND WIND DATA. . ERUPTION DETAILS: ALMOST CONTINUAL STEAM EMISSIONS WITH OCCASIONAL PULSES OF ASH. . DETAILS OF ASH: NO ASH CAN BE SEEN IN SATELLITE IMAGERY THROUGH 1645 UTC BECAUSE OF THE DENSE WEATHER CLOUDS OVER THE AREA. . TRAJECTORY: UPPER AIR PATTERNS SUGGEST THAT ANY ASH BELOW FL240 WOULD MOVE TO THE WEST AT ABOUT 15 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 . 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 15/2330 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . BROWN . NNNN