FVXX21 KWBC 200730 . VOLCANIC ASH ADVISORY STATEMENT ISSUED 0730 UTC 20 MAR 1999 BY THE WASHINGTON VAAC . POPOCATEPETL 99-038 MEXICO 19.02N 98.62W MESSAGE NUMBER HAS BEEN CHANGED DUE TO A PREVIOUS ERROR IN NUMBERING . BACKGROUND: POPOCATEPETL MEXICO (1401-09) SUMMIT HEIGHT 17930 FT (5465 M) . SOURCES OF INFORMATION: GOES-8 INFRARED AND MULTISPECTRAL IMAGERY THROUGH 20/0715 UTC. 20/0000 UTC MEXICO CITY UPPER AIR SOUNDING. . ERUPTION DETAILS: CENAPRED REPORTS AN EXHALATION AT 20/0041 UTC TO FL400. . DETAILS OF ASH CLOUD: SKIES ARE CLEAR OVER THE VOLCANO HOWEVER NO ASH CLOUD IS VISIBLE IN THE SATELLITE IMAGERY AT THE MOMENT. . TRAJECTORY: UPPER AIR WIND DATA SUGGEST THAT ASH AT FL400 WOULD MOVE TOWARDS THE EAST AT OVER 50 KTS. . 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 AT 20/1330 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . NNNN