FVXX21 KWBC 310430 VOLCANIC ASH ADVISORY STATEMENT ISSUED 0430 UTC 31 DEC 1999 BY THE WASHINGTON VAAC . TUNGURAHUA 99-317 ECUADOR 1.47S 78.44W . BACKGROUND: TUNGURAHUA ECUADOR (1502-08) SUMMIT HEIGHT 16480 FT (5023 M) . SOURCES OF INFORMATION: GOES-8 INFRARED AND MULTISPECTRAL IMAGERY. GEOPHYSICAL INSTITUTE IN QUITO. 1800 UTC AVIATION NUMERICAL MODEL. . ERUPTION DETAILS: INTERMITTENT ASH AND STEAM EMISSIONS... . DETAILS OF ASH: THE ASH PLUME SEEN EARLIER IS NO LONGER VISIBLE IN THE SATELLITE IMAGERY THROUGH 31/0345 UTC. IN ADDITION CURRENT SATELLITE IMAGERY SHOWS EXTENSIVE MULTILAYERED CLOUDS OVER THE AREA MAKING DETECTION OF ASH VERY DIFFICULT. . TRAJECTORY: ANY REMAINING ASH AT FL190 WOULD MOVE TOWARD THE SOUTHWEST AT 5 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 31/1030 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . WALTER/SAB/NOAA/NESDIS . NNNN