FVXX21 KWBC 150530 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 0520 UTC 15 DEC 1999 BY THE WASHINGTON VAAC . TUNGURAHUA 99-249 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...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 15/0445 UTC. HOWEVER THE PRESENCE OF LOW LEVEL WEATHER CLOUDS MIGHT BE HINDERING ASH DETECTION. MOREOVER OCCASIONAL BRIEF PULSES OF ASH AT ABOUT FL220 HAVE BEEN OBSERVED IN THE PAST 24 HOURS AND THIS ASH MOVED TO THE WEST BEFORE DISSIPATING. . 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 15/1130 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . STREETT . NNNN