FVXX20 KWBC 180500 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 0500 UTC 18 DEC 1999 BY THE WASHINGTON VAAC . GUAGUA PICHINCHA 99-160 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 0415 UTC. THE SURFACE REPORT FROM QUITO REPORTS VOLCANIC ASH OVER THE STATION BUT THERE IS NO INDICATION OF AN ONGOING ERUPTION. . 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 18/1100 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . KARST/NOAA/NESDIS/SAB . NNNN