FVXX20 KWBC 231755 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 1755 UTC 24 MAR 1999 BY THE WASHINGTON VAAC . SOUFRIERE HILLS 99-061 WEST INDIES 16.72N 62.18W . BACKGROUND: SOUFRIERE HILLS MONTSERRAT (1600-05) SUMMIT HEIGHT 3000 FT (915 M) . SOURCES OF INFORMATION: MONTSERRAT VOLCANO OBSERVATORY...12 UTC UPPER-LEVEL AIR SOUNDING OVER GUADELOUPE. . ERUPTION DETAILS: ASH VENTING EVENT AROUND 24/1715 UTC. . DETAILS OF ASH CLOUD: THE MONTSERRAT VOLCANO OBSERVATORY INDICATED AN ERUPTION AT ABOUT 1715 UTC. CLOUD COVER OBSCURED THE OBSERVATORY'S VIEW BUT THEY ESTIMATED THE ASH TOPS TO BE FL200. . TRAJECTORY: ASH ABOVE FL180 WOULD MOVE EAST AT 20 TO 30 KNOTS. AT OR BELOW FL100 ASH WOULD MOVE WEST TO SOUTHWEST AT 15 TO 20 KNOTS. BETWEEN FL100 AND FL180 THE WIND VEERS SHARPLY WITH HEIGHT. . THIS AND OTHER VOLCANIC ASH ADVISORY STATEMENTS OFTEN ACCOMPANIED BY A MAP DEPICTING ASH LOCATION ARE AVAILABLE AT INTERNET URL ADDRESS www.ssd.noaa.gov/VAAC/messages.html (all lower case except /VAAC/) . OUTLOOK: SEE SIGMETS. . THE NEXT MESSAGE WILL BE ISSUED WITHIN THE HOUR. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . NNNN