FVXX20 KWBC 281600 . VOLCANIC ASH ADVISORY STATEMENT-WATCH ISSUED 1600 UTC 28 FEB 1999 BY THE WASHINGTON VAAC . COLIMA 99-023 MEXICO 19.51N 103.62W . BACKGROUND: COLIMA MEXICO (1401-04) SUMMIT HEIGHT 13451 FT (4100 M) THE WATCH VAAS FOR COLIMA IS BEING DISCONTINUED AT THIS TIME BUT WILL BE REACTIVATED IF CONDITIONS WARRANT. THE COLIMA CENTER OF ENVIRONMENTAL RESEARCH REPORTS THAT THE WARNING SIGNS FOR A POTENTIAL EXPLOSIVE ERUPTION HAVE DECREASED. HOWEVER THE VOLCANO REMAINS SOMEWHAT UNSTABLE AND CAUTION SHOULD BE EXERCISED. . WE WILL CONTINUE TO MONITOR THE AREA AND IF THERE IS AN ASH CLOUD OBSERVED OR REPORTED AT ANY ALTITUDE A VOLCANIC ASH ADVISORY STATEMENT WARNING WILL BE ISSUED AS SOON AS POSSIBLE. . THE WATCH VAAS IS ISSUED ONLY FOR SEISMICALLY MONITORED VOLCANOES AND BASED ON INFORMATION RECEIVED FROM THE GEOLOGICAL COMMUNITY. A WATCH VAAS WILL BE ISSUED DAILY WHEN INFORMATION IS RECEIVED TO INDICATE THAT A VOLCANO IS RESTLESS AND HAS THE POTENTIAL FOR AN EXPLOSIVE ERUPTION WITH LITTLE OR NO WARNING. NON-EXPLOSIVE LOW LEVEL AND NEAR SUMMIT ACTIVITY MAY BE OCCURRING AT PRESENT. SEE NOAA-ARL HOMEPAGE FOR TEST-VAFTAD AT: HTTP://WWW.ARL.NOAA.GOV/VAFTAD.HTML (ALL LOWER CASE) . THIS WILL BE THE FINAL STATEMENT ON THIS EVENT UNLESS CONDITIONS CHANGE. . NNNN