Flash Flooding in California, July 14 to 15, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
910 AM PDT MON JUL 14 2008

.SYNOPSIS...A MOIST AND UNSTABLE AIR MASS WILL REMAIN OVER THE AREA
THROUGH TUESDAY RESULTING IN ISOLATED TO SCATTERED THUNDERSTORMS...
ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. SOME STORMS MAY
PRODUCE HEAVY RAINFALL. STORM COVERAGE WILL GRADUALLY DECREASE BY
THE MIDDLE OF THE WEEK AS DRIER SOUTHWEST FLOW DEVELOPS. &&

.UPDATE...OVERALL MOIST AND UNSTABLE TODAY WITH UPPER TROUGH STILL
OVER THE AREA. ISOLATED TO SCATTERED THUNDERSTORMS EXPECTED TO
DEVELOP THROUGHOUT THE DAY. FORECAST IN GOOD SHAPE AND NO UPDATES
PLANNED.
&&

.AVIATION...FOR MCCARRAN...PARTLY CLOUDY SKIES ACROSS THE LAS VEGAS
VALLEY THROUGH 18Z. ISOLATED THUNDERSTORM COVERAGE IS EXPECTED ALONG
ALL APPROACH CORRIDORS AND WITHIN THE LAS VEGAS VALLEY DURING THE
AFTERNOON.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SOME LIGHT TO MODERATE SHOWERS REMAIN OVER NORTHERN
PORTIONS OF MOHAVE COUNTY...BUT ARE EXPECTED TO DIMINISH BY 14Z.
THUNDERSTORMS WILL ONCE AGAIN DEVELOP ACROSS THE REGION AFTER 18Z
AND CONTINUE INTO THE EVENING HOURS.
&&

.PREV DISCUSSION...330 AM PDT MON JUL 14...SHORT TERM...VERY LITTLE
CHANGE TO THE OVERALL FORECAST PACKAGE AS MOIST AND UNSTABLE
CONDITIONS REMAIN ACROSS THE CWA. MODELS INDICATE THAT FAIRLY
UNIFORMED CONDITIONS CONTINUE...WITH THETA-E/ PREC WATER/CAPE/NEG
LI...NOT REALLY FOCUSING IN ANY SPECIFIC AREA FOR TODAY. FLOW ALOFT
REMAINS LIGHT AND ALTHOUGH HEAVY RAIN MAY CAUSE SOME LOCALIZE FLOOD
PROBLEMS...LACK OF STRONG FOCUS DOES NOT LEAD TO A FLASH FLOOD WATCH
ATTM. SITUATION WILL NEED TO BE MONITORED CLOSELY DURING THE DAY
HOWEVER. TUESDAY WILL BE SIMILAR TO TODAY...HOWEVER MODELS CONTINUE
TO INDICATE THAT INCREASED SOUTHWEST FLOW ALOFT LOOKED FOR INTO
WEDNESDAY WHICH SHOULD BRING A DRIER AIRMASS TO AT LEAST THE WESTERN
PORTION OF THE CWA AND HAVE CONFINED THUNDERSTORMS TO MAINLY THE
EASTERN HALF WHILE EXPECTED COVERAGE TO BE LESS THAN TUESDAY.
TEMPERATURES WILL REMAIN A CHALLENGE DUE TO CLOUD COVER/SHOWERS.
WENT WITH MOS RESULTING IN A FEW DEGREES OF WARMING INTO THE MIDDLE
OF THE WEEK AS DRIER AIR MOVES IN.

.LONG TERM...ONCE AGAIN ONLY MINOR CHANGES MADE TO THE FORECAST.
MODELS CONTINUE TO SHOW A SLOW DRYING TREND FROM WEST TO EAST TOWARD
THE END OF THE WEEK AS AN UPPER LEVEL LOW PUSHES THROUGH THE PACIFIC
NORTHWEST. ALTHOUGH THE SOUTHWEST FLOW INCREASES ALOFT OVER THE
WESTERN ZONES...MONSOONAL MOISTURE IS LIKELY TO REMAIN OVER THE FAR
EASTERN ZONES. KEPT THE SLIGHT CHANCE TO CHANCE POPS IN THE FORECAST
THROUGH THE PERIOD OVER MOHAVE COUNTY WITH LOWER POPS AS YOU GO
WEST. WITH THE DRIER AIR MOVING INTO THE REGION TEMPERATURES WILL
SLOWLY INCREASE. RIGHT NOW WE ARE NOT LOOKING FOR A SIGNIFICANT
WARMING TREND...BUT IT LOOKS LIKE TEMPERATURES WILL REMAIN SLIGHTLY
ABOVE NORMAL THROUGH THE PERIOD.
&&

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

HARRISON/SALMEN/JENSEN/GORELOW

HTTP://WEATHER.GOV/LASVEGAS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LAS VEGAS NV
556 AM PDT MON JUL 14 2008

AZZ001>003-036-CAZ519>527-NVZ014>022-150000-
NORTHWEST PLATEAU-LOWER COLORADO RIVER VALLEY-NORTHWEST DESERTS-
LAKE MEAD NATIONAL RECREATION AREA-EASTERN SIERRA SLOPES-
OWENS VALLEY-WHITE MOUNTAINS OF INYO COUNTY-
DEATH VALLEY NATIONAL PARK-WESTERN MOJAVE DESERT-
EASTERN MOJAVE DESERT-MORONGO BASIN-CADIZ BASIN-
SAN BERNARDINO COUNTY-UPPER COLORADO RIVER VALLEY-
ESMERALDA AND CENTRAL NYE COUNTY-LINCOLN COUNTY-
NORTHEAST CLARK COUNTY-WESTERN CLARK AND SOUTHERN NYE COUNTY-
SHEEP RANGE-SPRING MOUNTAINS-LAS VEGAS VALLEY-
SOUTHERN CLARK COUNTY-
556 AM PDT MON JUL 14 2008 /556 AM MST MON JUL 14 2008/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST
ARIZONA...CALIFORNIA AND SOUTHERN NEVADA.

.DAY ONE...TODAY AND TONIGHT

A MOIST AND UNSTABLE AIR MASS WILL REMAIN OVER THE AREA TODAY FOR
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS. IN ADDITION TO
DANGEROUS LIGHTNING AND POSSIBLY STRONG WINDS...LOCAL HEAVY RAIN
COULD PRODUCE ISOLATED FLASH FLOODING.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

SCATTERED THUNDERSTORMS CAN BE EXPECTED AGAIN TUESDAY FOLLOWED BY
DECREASING COVERAGE WEDNESDAY AND INTO THE WEEKEND AS DRIER SOUTHWEST
FLOW DEVELOPS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY. SPOTTERS ARE ALWAYS
ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER AS SOON AS IT IS
SAFE TO DO SO.