FVXX21 KWBC 030730 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 0730 UTC 03 DEC 1999 BY THE WASHINGTON VAAC . TUNGURAHUA 99-198 ECUADOR 1.47S 78.44W . BACKGROUND: TUNGURAHUA ECUADOR (1502-08) SUMMIT HEIGHT 16480 FT (5023 M) . SOURCES OF INFORMATION: GOES-8 MULTISPECTRAL AND INFRARED IMAGERY. AVIATION MODEL WIND FORECAST. . ERUPTION DETAILS: CONTINUOUS STEAM AND ASH EMISSIONS AND OCCASIONAL EXPLOSIONS OF ASH. . DETAILS OF ASH: THE VOLCANO HAS UNDERGONE A RELATIVELY QUIET STAGE IN THE PAST SEVERAL DAYS. NO ASH CAN BE SEEN IN SATELLITE IMAGERY THROUGH 0645 UTC. THE VOLCANO REMAINS IN AN UNSTABLE STATE AND COULD PRODUCE A MODERATE TO LARGE ERUPTION AT ANYTIME. . TRAJECTORY: UPPER AIR PATTERNS BASED ON NUMERICAL GUIDANCE SUGGEST ANY ASH FROM THE SUMMIT UP TO FL300 WOULD MOVE SOUTHWEST AT 5 TO 10 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. . HUGHES/NOAA/NESDIS/SAB . ....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 03/1330 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . NNNN