FVXX22 KWBC 181831 VOLCANIC ASH ADVISORY ISSUED: 2003JUN18/1845Z VAAC: WASHINGTON VOLCANO: ANATAHAN 0804-20 LOCATION: N1621E14540 AREA: MARIANA ISLANDS SUMMIT ELEVATION: 2585 FT (788 M) ADVISORY NUMBER: 2003/163 INFORMATION SOURCE: GOES-9 IMAGERY. GFS MODEL WINDS FORECAST. ERUPTION DETAILS: CONTINUOUS ASH AND GAS EMISSIONS SINCE MAY 10. OBS ASH DATE/TIME: 18/1802Z OBS ASH CLOUD: ASH NOT IDENTIFIABLE FROM SATELLITE DATA. WINDS SFC/FL090 MOVING W 15-20 KNOTS. FCST ASH CLOUD +6H: SEE SIGMETS. REMARKS: THE WEATHER CLOUDS HAVE BROKEN UP OVER THE SUMMIT. HOWEVER A THIS TIME ASH IS NOT DETECTABLE ON IMAGERY. THIS DOES NOT MEAN THAT ASH IS NOT PRESENT...LOW LEVEL ASH CAN BE VERY DIFFICULT TO DETECT AT NIGHT...SO WILL WAIT FOR FIRST VISIBLE IMAGES. IF ASH IS PRESENT IT WOULD BE MOVING WEST AT ABOUT 20 KNOTS...GALLINA NEXT ADVISORY: WILL BE ISSUED BY 2003JUN19/0045Z. NNNN