FVXX22 KWBC 160530 VOLCANIC ASH ADVISORY STATEMENT ISSUED 0530 UTC 16 DEC 1999 BY THE WASHINGTON VAAC . SAN CRISTOBAL 99-019 NICARAGUA 12.7N 87.0W . BACKGROUND: SAN CRISTOBAL NICARAGUA (1404-02) SUMMIT HEIGHT 5725 FT (1745 M) . SOURCES OF INFORMATION: GOES-8 VISIBLE INFRARED AND MULTISPECTRAL IMAGERY...1800 UTC AVIATION MODEL WIND FORECAST . ERUPTION DETAILS: LIGHT VENTING OF GASES AND POSSIBLY ASH. . DETAILS OF ASH CLOUD: SINCE NIGHTFALL WITH ONLY INFRARED AND MULTISPECTRAL SATELLITE IMAGERY AVAILABLE IT HAS NOT BEEN POSSIBLE TO SEE ASH IN SATELLITE IMAGERY. HOWEVER IN THE LAST VISIBLE SATELLITE IMAGES OF DECEMBER 15 A THIN PLUME OF ASH OR GASES AT ABOUT FL080 WAS SEEN EXTENDING FROM THE VOLCANO TOWARD THE WEST SOUTHWEST. AT 15/2245 UTC THE PLUME WAS ESTIMATED TO BE 300 KM (162 NMI) LONG AND EXTEND TO THE POINT 11.5N 89.5W OVER THE PACIFIC OCEAN. THE PLUME COULD BE SEEN ONLY IN VISIBLE IMAGERY AND COULD NOT BE DISCERNED IN INFRARED OR MULTISPECTRAL IMAGERY. . TRAJECTORY: BEFORE NIGHTFALL GASES AND POSSIBLE ASH WERE SEEN MOVING TO THE WEST SOUTHWEST AT LESS THAN 20 KNOTS. . REAL TIME SATELLITE IMAGERY ALONG WITH 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/washington.html (all lower case except /VAAC/) . OUTLOOK: SEE LATEST SIGMETS. . EFFECTIVE JANUARY 3 2000 AT 0000 UTC... ALL REFERENCES TO LATITUDE AND LONGITUDE IN VOLCANIC ASH ADVISORY STATEMENTS WILL BE IN DEGREES AND MINUTES OF A DEGREE. EXAMPLE: 16.70N 62.20W WILL BE 1642N6212W . THE NEXT STATEMENT WILL BE ISSUED BY 16/1130 UTC. . PLEASE REFER TO SIGMETS FOR CURRENT WARNINGS. . STREETT . NNNN