FVXX21 KWBC 230030 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 0020 UTC 23 DEC 1999 BY THE WASHINGTON VAAC . TUNGURAHUA 99-281 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 AND WIND DATA...1800 UTC AVIATION MODEL WIND FORECAST. . ERUPTION DETAILS: CONTINUAL STEAM AND ASH EMISSION. . DETAILS OF ASH: MULTISPECTRAL SATELLITE IMAGERY SHOWS A NARROW ASH PLUME EXTENDING FROM THE SUMMIT TOWARD THE SOUTHWEST. AT 2345 UTC THE PLUME IS ABOUT 80 KM (43 NMI) LONG AND 10 KM (5 NMI) WIDE AND EXTENDS FROM THE SUMMIT TO THE POINT 2.1S 79.0W. THIS ASH IS ESTIMATED TO BE BELOW FL230. THERE MIGHT BE ADDITIONAL FAINT ASH IN THE AREA WHICH IS NOT DISCERNIBLE IN SATELLITE IMAGERY AGAINST THE BACKGROUND OF MID-LEVEL WEATHER CLOUDS. . TRAJECTORY: ASH BETWEEN FL160 AND FL230 IS MOVING TO THE SOUTHWEST AT 10 TO 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 23/0630 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . STREETT/SAB/NOAA/NESDIS . NNNN