SAN CRISTOBAL 99-002 NICARAGUA 12.7N 87.0W

BACKGROUND: SAN CRISTOBAL NICARAGUA (1404-02)
SUMMIT HEIGHT 5725 FT (1745 M)

SOURCES OF INFORMATION: GOES-8 INFRARED AND MULTISPECTRAL
IMAGERY...1800 UTC AVIATION MODEL SOUNDING DATA.

ERUPTION DETAILS: CHINANDEGA NICARAGUA SURFACE OBSERVATION AT 1900
UTC INDICATED THE PRESENCE OF VOLCANIC ASH OVER THE STATION.

DETAILS OF ASH CLOUD: SATELLITE IMAGERY THROUGH 22/0145 UTC DOES
NOT INDICATE ANY ASH CLOUDS OVER OR ADJACENT TO TO VOLCANO SITE. THE
ASH SEEN EARLIER WAS DETECTED ONLY IN VISIBLE IMAGERY WHICH SUPPORTS
THE LOW-LEVEL HEIGHT ASSIGNMENT. THERE IS STILL SUGGESTION OF
ACTIVITY THOUGH AS THERE IS AN OCCASIONAL HOT SPOT SEEN IN
MULTISPECTRAL IMAGERY. THIS IMPLIES AT LEAST THE POSSIBILITY THAT
ASH COULD STILL BE VENTING AS IT WAS EARLIER BUT ONLY AT VERY LOW
ALTITUDES. ANY ASH IS ESTIMATED TO BE FROM THE SUMMIT TO FL100.

MASAYA 99-001 NICARAGUA 11.98N 86.16W

BACKGROUND: MASAYA NICARAGUA (1401-10)
SUMMIT HEIGHT 2083 FT (635 M)

SOURCES OF INFORMATION: GOES-8 VISIBLE...INFRARED...AND
MULTISPECTRAL SATELLITE IMAGERY...21/1200 UTC AVIATION MODEL DATA

ERUPTION DETAILS: POSSIBLE ASH AND STEAM EMISSIONS BEGINNING BETWEEN
1900 AND 2000 UTC...POSSIBLE EXPLOSION AROUND 2200 UTC.

DETAILS OF ASH CLOUD: A VOLCANO WHICH HAS HAD A LONG HISTORY OF
BEING VERY ACTIVE MAY WELL HAVE AWAKENED AGAIN AS OF TODAY.
SATELLITE IMAGERY FROM GOES-8 STRONGLY SUGGESTS THAT THERE IS SOME
ACTIVITY AT OR VERY NEAR THE MASAYA VOLCANO SITE. THERE WAS SOME
WEAK SUGGESTION OF A PLUME OF POSSIBLE ASH OR SMOKE SEVERAL HOURS
AGO MOVING TO THE WEST-SOUTHWEST BUT THERE HAS BEEN NO OTHER
INFORMATION THAT WOULD INDICATE ANY ERUPTIONS OR ACTIVITY. SATELLITE
IMAGERY HOWEVER OVER THE TWO HOURS IS INDICATING A PERIODIC HOT SPOT
AND THE LAST VISIBLE IMAGES SUGGEST THAT SOME TYPE OF EXPLOSION MAY
HAVE OCCURRED AT AROUND 2200 UTC. AT 2215 UTC THERE IS A PLUME OF
POSSIBLE ASH SEEN AND IT IS ESTIMATED TO BE AT FL025. THIS MAKES THE
ACTIVITY NEAR-SUMMIT. THE PLUME EXTENDS 37 KM (20 NMI) TO THE WEST-SOUTHWEST