Flash Flood Warning 3, NWS Las Vegas, NV

MOJAVE DESERT/SOUTHERN GREAT BASIN AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
900 AM PDT SUN JUL 19 1998

SYNOPSIS...THE UPPER LEVEL HIGH PRESSURE SYSTEM JUST NORTHEAST OF LAS
VEGAS WILL MOVE SLOWLY EAST TOWARD THE 4-CORNERS AREA BY MONDAY.
THIS WILL ALLOW FOR A GRADUAL INCREASE IN MONSOONAL MOISTURE ACROSS
THE MOJAVE DESERT AND SOUTHERN GREAT BASIN LEADING TO A BETTER CHANCE
OF LATE DAY THUNDERSTORMS EARLY THIS WEEK.

DISCUSSION...MID AND UPPER LEVEL MOISTURE HAD INCREASED CONSIDERABLY
ACROSS THE CWA OVER THE LAST 24 HOURS PER WATER VAPOR LOOP. 12Z DRA
SOUNDING REFLECTED THIS INCREASE AS WELL AS AN INCREASE IN LOW LEVEL
MOISTURE...WHICH WAS SURGING NORTH ALONG THE COLORADO RIVER VALLEY.
INVERTED-V TYPE PROFILE WILL LEAVE THE REGION SUSCEPTIBLE TO STRONG
DOWNBURST WINDS FROM THE THUNDERSTORMS WHICH DEVELOP THIS AFTERNOON
AND EVENING. WILL CONTINUE WITH SCATTERED COVERAGE ACROSS MOST OF
MOHAVE COUNTY WHERE CAPES RISE TO AS MUCH AS 1000 J/KG LATER THIS
AFTERNOON AND LIFTED INDICES DROP TO -2. WITH INSTABILITY AND LOW
LEVEL MOISTURE ONLY MARGINAL ACROSS A GOOD PORTION OF SOUTHERN
NEVADA...WILL LEAVE POPS IN THE ISOLATED CATEGORY...MAINLY OVER THE
MOUNTAINS. CURRENT FORECAST LOOKS IN GOOD SHAPE. NO CHANGES NEEDED AT
THIS TIME.

LAS 111. MATUSIEWICZ