FVXX20 KWBC 181100 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 1100 UTC 18 DEC 1999 BY THE WASHINGTON VAAC . GUAGUA PICHINCHA 99-161 ECUADOR 0.17S 78.60W . BACKGROUND: GUAGUA PICHINCHA ECUADOR (1502-02) SUMMIT HEIGHT 15695 FT (4784 M) . SOURCES OF INFORMATION: THE GEOPHYSICAL INSTITUTE IN ECUADOR. GOES-8 VISIBLE INFRARED AND MULTISPECTRAL IMAGERY. U.S. NUMERICAL MODEL WIND FORECAST. . ERUPTION DETAILS: THE GEOPHYSICAL INSTITUTE REPORTED AN EXPLOSIVE ERUPTION AT 2004 UTC. . DETAILS OF ASH CLOUD: THE ASH FROM THE EARLIER ERUPTION IS NO LONGER DISCERNIBLE IN SATELLITE IMAGERY THRU 1015 UTC. THE LATEST SURFACE REPORT FROM QUITO DOES NOT MENTION VOLCANIC ASH OVER THE STATION. . TRAJECTORY: UPPER AIR PATTERN AND NUMERICAL GUIDANCE SUGGEST ASH AT FL300 TO MOVE NORTH AT 10 KNOTS AND ASH AT FL400 TO MOVE EAST 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 AND VAFTAD. . 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 AT 18/1700 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . KARST/NOAA/NESDIS/SAB . NNNN