Flash Flood in Nevada, July 6, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
930 AM PDT THU JUL 6 2006

.SYNOPSIS...A RELATIVELY MOIST AND UNSTABLE AIR MASS WILL REMAIN
OVER EASTERN NEVADA AND WESTERN ARIZONA INTO THE WEEKEND...RESULTING
IN SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.
SOUTHWESTERN NEVADA AND MOST OF SOUTHEAST CALIFORNIA WILL BE IN
DRIER AIR...AND WILL SEE ONLY A FEW THUNDERSTORMS.
&&

.UPDATE...UPPER AIR DISTURBANCE CONTINUES TO TRACK TOWARD MOHAVE
COUNTY. SEVERAL DIFFERENT CLUSTERS OF LIGHTENING HAVE OCCURRED NEAR
CENTER OF ACTIVITY WITH A FEW SMALLER GROUPS AHEAD OF IT. HAVE
ISSUED A NOW FOR ONE GROUP OF STORMS OVER COLORADO CITY. DEW POINTS
CONTINUE TO BE HIGH ESPECIALLY NEAR THE CAL-NEV-ARI BORDER WITH TWO
PLACES HAVING VALUES OVER 70. AM ISSUING UPDATED GRIDS AND A NEW ZFP
TO REFLECT MORE PRECIPITATION IN MOHAVE COUNTY. WILL NEED TO KEEP A
VERY CLOSE EYE THERE TO SEE IF A FLASH FLOOD WATCH IS NECESSARY.
&&

.SHORT TERM...WATER VAPOR CLEARLY SHOWS MID LEVEL DRYING ASSOCIATED
WITH THE SHORTWAVE TROUGH MOVING IN FROM THE PACIFIC. THIS DRYING IS
IMPINGING ON OUR WESTERN CWFA AT THIS TIME. HOWEVER...IN THE
SOUTHEASTERLY FLOW OVER ARIZONA...A MOIST IMPULSE IS ROTATING NORTH
TOWARDS OUR EASTERN CWFA. YESTERDAY...THE CALIFORNIA SHORTWAVE WAS
EXPECTED TO BRING DRIER SOUTHWEST FLOW TO THE NORTHWEST TWO THIRDS
OR SO OF OUR AREA. HOWEVER...WITH THE ARIZONA WAVE NOW IN THE
PICTURE...THIS FORECAST WILL BE BASED ON THE TWO WAVES ESSENTIALLY
BATTLING TO A DRAW. THUS...THUNDERSTORM CHANCES FOR THIS AFTERNOON
AND EVENING WERE PAINTED IN ABOUT THE SAME AREAS WHICH EXPERIENCED
STORMS WEDNESDAY. STILL GOING WITH THE IDEA OF REDUCING POPS FROM
THE WEST A LITTLE BIT ON FRIDAY...WITH LITTLE ADDITIONAL CHANGE OVER
THE WEEKEND...BUT CONFIDENCE IS NOT HIGH. TEMPERATURES PRETTY CLOSE
TO SEASONAL NORMS OVERALL TODAY AND TOMORROW...WITH POINT FORECASTS
AGAIN HIGHLY DEPENDENT ON LATE MORNING/EARLY AFTERNOON THUNDERSTORM
DEVELOPMENT. IF THE AFOREMENTIONED DRYING TREND OVER THE WEEKEND
ACTUALLY OCCURS...TEMPERATURES WOULD RISE A FEW DEGREES ABOVE NORMAL.

.LONG TERM...MODELS CONTINUE TO SHOW MOISTURE REMAINING IN PLACE
OVER THE SOUTHERN AND EASTERN AREAS OF THE CWA SUNDAY AND MONDAY AS
A WEAK SHORTWAVE APPROACHES THE WEST COAST. GFS SHOWS THIS TROUGH TO
DEEPEN SLIGHTLY ON TUESDAY AND FINALLY KICK THE LOWER LEVEL MOISTURE
EAST. ALTHOUGH I DO THINK THE SOUTHWEST FLOW WILL INCREASE ON
TUESDAY...STILL HAVING A HARD TIME BELIEVING THE SHORTWAVE WILL BE
AS DEEP AS THE MODELS INDICATE. EXPECT TO SEE A COUPLE DEGREES OF
TEMPERATURE DROP...BUT WILL KEEP NUMBERS SLIGHTLY HIGHER THAN
GUIDANCE. WEDNESDAY AND THURSDAY LOOK TO REMAIN DRY OVER THE
FORECAST AREA AND HAVE KEPT ALL MENTION OF POPS OUT OF THE ZONES.
&&

.AVIATION...SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON AFTER 20Z AND AFFECT PORTIONS OF THE PEACH SPRINGS AND
MORMON MESA CORRIDORS. THUNDERSTORMS WILL ALSO BE POSSIBLE ALONG THE
BEATTY AND DAGGETT CORRIDORS...HOWEVER COVERAGE IS EXPECTED TO BE
LESS. TAFS AND TWEBS ADEQUATELY DESCRIBE EXPECTED WEATHER CONDITIONS
FOR AREA TERMINALS. SEE TAFS FOR KLAS... KVGT... KDRA... KBIH...
KDAG... KEED.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
.NV...NONE.
.AZ...NONE.
.CA...NONE.

BELL/MORGAN/GORELOW

HTTP://WEATHER.GOV/LASVEGAS