FVXX21 KWBC 271400 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 1400 UTC 27 OCTOBER 1999 BY THE WASHINGTON VAAC . TUNGURAHUA 99-037 ECUADOR 1.47S 78.44W . BACKGROUND: TUNGURAHUA ECUADOR (1502-08) SUMMIT HEIGHT 16480 FT (5023 M) . SOURCES OF INFORMATION: GOES-8 VISBLE INFRARED AND MULTISPECTRAL IMAGERY..GEOPHYSICAL INSTITUTE AND NATIONAL WEATHER SERVICE NUMERICAL MODELS . ERUPTION DETAILS: OCCASIONAL VENTING OF ASH AND STEAM. . DETAILS OF ASH: GOES-8 SATELLITE IMAGERY THROUGH 27/1315 UTC SHOWS A RATHER EXTENSIVE AREA OF MULTILAYERED CLOUDS AROUND THE VOLCANO SITE. AT THIS TIME THERE IS NO ASH DISCERNIBLE. HOWEVER THERE HAS BEEN AN EXTENSIVE AMOUNT OF NEAR-SUMMIT ACTIVITY OVER THE LAST WEEK WITH ASH OBSERVED JUST ABOVE THE SUMMIT. IF THERE IS CURRENTLY NEAR-SUMMIT ASH EMBEDDED WITHIN THE MULTILAYERED CLOUDS THEN IT WOULD BE AT FL150-FL180. . THE QUITO GEOPHYSICAL INSTITUTE HAS BEEN REPORTING A LARGE AMOUNT OF INSTABILITY WITH THE VOLCANO. A MORE IMPRESSIVE ERUPTION COULD OCCUR AT ANY TIME AND SO CAUTION IS STRONGLY ADVISED. . TRAJECTORY: NATIONAL WEATHER SERVICE NUMERICAL METEOROLOGICAL MODELS INDICATE NOW THAT ANY ASH AT FL180 WOULD MOVE TOWARD NORTH AT 15 KT. . 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. . THE NEXT STATEMENT WILL BE ISSUED AROUND 27/2000 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . ORRISON . NNNN