FVXX20 KWBC 180730 VOLCANIC ASH ADVISORY ISSUED 0730 UTC 18 SEP 2000 BY THE WASHINGTON VAAC . SOUFRIERE HILLS 00-246 WEST INDIES 1643N 6211W . BACKGROUND: SOUFRIERE HILLS MONTSERRAT (1600-05) SUMMIT HEIGHT 3000 FT (915M) . SOURCES OF INFORMATION: INFRARED AND MULTISPECTRAL SATELLITE IMAGERY. THE MONTSERRAT VOLCANO OBSERVATORY. 18/0000 UTC GUADELOUPE UPPER AIR SOUNDING. . ERUPTION DETAILS: PERIODIC EXPLOSIONS AND EMISSIONS . DETAILS OF ASH CLOUD: NO ASH IS VISIBLE IN SATELLITE IMAGERY THROUGH 18/0715 UTC ALTHOUGH SCATTERED CLOUDS PERSIST IN THE AREA AROUND THE VOLCANO. THE MVO REPORTS THAT THERE HAS BEEN AT LEAST ONE EXPLOSION PER DAY AND THESE TYPICALLY OCCUR AT NIGHT. THEREFORE THIS ADVISORY WILL CONTINUE AS LONG AS THERE IS A CREDIBLE THREAT TO AVIATION IN THE AREA. . TRAJECTORY: UPPER AIR PATTERNS SUGGEST ANY ASH FROM SUMMIT LEVEL TO FL100 WOULD MOVE WEST AT 15 TO 30 KNOTS. . OUTLOOK: SEE SIGMETS. . THE NEXT ADVISORY WILL BE ISSUED BY 18/1330 UTC. . REAL TIME SATELLITE IMAGERY AND VOLCANIC ASH ADVISORIES 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/) . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . CLARK . NNNN