Flash Flood Watch 5, NWS Las Vegas, NV

892 
WGUS65 KVEF 311837
FFAVEF

FLOOD WATCH
NATIONAL WEATHER SERVICE LAS VEGAS NV
1137 AM PDT TUE JUL 31 2012

.A VERY MOIST AND UNSTABLE AIR MASS COMBINED WITH AN AREA OF LOW
PRESSURE OVER THE AREA WILL BRING POTENTIAL FOR HEAVY RAIN AND
FLASH FLOODING THROUGH THIS EVENING.

AZZ001>003-036-CAZ524>527-NVZ016-020>022-010500-
/O.CON.KVEF.FF.A.0005.000000T0000Z-120801T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NORTHWEST PLATEAU-LAKE HAVASU AND FORT MOHAVE-NORTHWEST DESERTS-
LAKE MEAD NATIONAL RECREATION AREA-EASTERN MOJAVE DESERT-
MORONGO BASIN-CADIZ BASIN-SAN BERNARDINO COUNTY-
UPPER COLORADO RIVER VALLEY-NORTHEAST CLARK COUNTY-
LAS VEGAS VALLEY-SOUTHERN CLARK COUNTY-
1137 AM PDT TUE JUL 31 2012 /1137 AM MST TUE JUL 31 2012/

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 10 PM PDT /10 PM
MST/ THIS EVENING...

THE FLASH FLOOD WATCH CONTINUES FOR

* PORTIONS OF NORTHWEST ARIZONA...CALIFORNIA AND SOUTHERN 
  NEVADA...INCLUDING THE FOLLOWING AREAS...IN NORTHWEST 
  ARIZONA...LAKE HAVASU AND FORT MOHAVE...LAKE MEAD NATIONAL 
  RECREATION AREA...NORTHWEST DESERTS AND NORTHWEST PLATEAU. IN 
  CALIFORNIA...CADIZ BASIN...EASTERN MOJAVE DESERT...MORONGO 
  BASIN AND SAN BERNARDINO COUNTY-UPPER COLORADO RIVER VALLEY. 
  IN SOUTHERN NEVADA...LAKE MEAD NATIONAL RECREATION AREA...LAS 
  VEGAS VALLEY...NORTHEAST CLARK COUNTY AND SOUTHERN CLARK 
  COUNTY. 

* UNTIL 10 PM PDT /10 PM MST/ THIS EVENING

* AN UNUSUALLY MOIST AIR MASS IS IN PLACE OVER MOHAVE...CLARK 
  AND EASTERN SAN BERNARDINO COUNTIES. IN ADDITION...AN AREA OF 
  LOW PRESSURE WILL LINGER OVER THE SAME AREA PROVIDING 
  SUFFICIENT LIFT AND INSTABILITY FOR THUNDERSTORM DEVELOPMENT. 
  STORMS THAT FORM WILL HAVE THE POTENTIAL TO PRODUCE VERY HEAVY 
  RAIN AND SUBSEQUENT FLASH FLOODING TODAY THROUGH THIS EVENING. 

* TRAVELERS SHOULD BE ALERT FOR THE POTENTIAL FOR WATER TO COVER
  LOW SPOTS INCLUDING ANY ROADS THAT RUN THROUGH WASHES. ROCKS AND
  MUD MAY WASH ONTO ROADS DUE TO RUNOFF. DIRT AND GRAVEL SECONDARY
  ROADS MAY WASH OUT OR BE IMPASSABLE. STORM DRAINS AND FLOOD
  CONTROL CHANNELS COULD SEE RAPIDLY FLOWING WATER AS WELL AS
  DEBRIS. IN ADDITION...RUNOFF MAY CAUSE FLOODING WELL DOWNSTREAM
  FROM WHERE ANY RAIN FALLS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION
AND PERSONS IN AND NEAR THE WATCH AREA SHOULD BE ALERT TO THE
POTENTIAL FOR HEAVY RAINFALL.

&&

$$

MORGAN

422 
WGUS65 KVEF 010359
FFAVEF

FLOOD WATCH
NATIONAL WEATHER SERVICE LAS VEGAS NV
859 PM PDT TUE JUL 31 2012

AZZ001>003-036-CAZ524>527-NVZ016-020>022-010500-
/O.CAN.KVEF.FF.A.0005.000000T0000Z-120801T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
NORTHWEST PLATEAU-LAKE HAVASU AND FORT MOHAVE-NORTHWEST DESERTS-
LAKE MEAD NATIONAL RECREATION AREA-EASTERN MOJAVE DESERT-
MORONGO BASIN-CADIZ BASIN-SAN BERNARDINO COUNTY-
UPPER COLORADO RIVER VALLEY-NORTHEAST CLARK COUNTY-
LAS VEGAS VALLEY-SOUTHERN CLARK COUNTY-
859 PM PDT TUE JUL 31 2012 /859 PM MST TUE JUL 31 2012/

...FLASH FLOOD WATCH IS CANCELLED...

THE FLASH FLOOD WATCH FOR PORTIONS OF NORTHWEST ARIZONA...
SOUTHEAST CALIFORNIA AND SOUTHERN NEVADA HAS BEEN CANCELLED.
THUNDERSTORMS LARGELY DISSIPATED ACROSS THE WATCH AREA DURING
THE EVENING. THOUGH ISOLATED THUNDERSTORMS WILL STILL BE POSSIBLE
OVERNIGHT...CONDITIONS ARE NO LONGER FAVORABLE FOR EXTENSIVE FLASH
FLOODING AND THE FLASH FLOOD WATCH HAS BEEN CANCELLED.

$$

JA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
938 PM PDT MON JUL 30 2012

.SYNOPSIS...MONSOON MOISTURE WILL BRING CHANCES FOR THUNDERSTORMS TO
MUCH OF THE REGION THROUGH THE WEEK. HEAVY RAIN AND FLASH FLOODING
WILL BE A THREAT EACH DAY.
&&

.UPDATE...THUNDERSTORMS WERE RELATIVELY SPARSE OVER THE FORECAST
AREA THIS EVENING IN SPITE OF THE OBVIOUS CIRCULATION ASSOCIATED
WITH THE INVERTED TROUGH EXTENDING UP THE SOUTHEAST NEVADA BORDER.
AN EXTENSIVE AREA OF LIGHT SHOWERS WAS ALIGNED WITH THE TROUGH AXIS
BETWEEN LAS VEGAS AND KINGMAN. THIS FEATURE AND THE DEEP MOIST AND
UNSTABLE AIR WILL LINGER OVER THE SAME AREA THROUGH WEDNESDAY. THE
00Z NAM AND GFS INDICATE THE CLOSED CIRCULATION CURRENTLY ALONG THE
SOUTHERN CALIFORNIA/MEXICO BORDER WILL SLOWLY LIFT UP INTO EASTERN
SAN BERNARDINO COUNTY BY TUESDAY AFTERNOON. THIS MAY ENHANCE
CONVECTION OVER THE AREA SOUTH OF I-40 LATE TONIGHT THROUGH TUESDAY
MORNING. HOWEVER...WITH THE RECENT RADAR TRENDS INDICATING SUBDUED
THUNDERSTORMS...THE FLASH FLOOD WATCH WILL BE ALLOWED TO EXPIRE
ON SCHEDULE. EXTENSIVE CLOUD COVER WILL LIMIT HEATING THROUGH EARLY
TUESDAY. THOUGH LOCALIZED FLASH FLOODING IS A GOOD BET AGAIN
TUESDAY...I AM HESITANT TO GO WITH ANOTHER FLASH FLOOD WATCH GIVEN
THE LACK OF THUNDERSTORM DEVELOPMENT SO FAR WITH THE INVERTED TROUGH.
WE WILL SEE HOW THINGS GO OVERNIGHT...IF THERE WERE A NEED...I THINK
THE MOST FAVORABLE AREAS WOULD BE OVER MOHAVE COUNTY AND SOUTH OF
I-15 IN EASTERN SAN BERNARDINO AND SOUTHERN CLARK COUNTIES NEAR THE
APPROACHING CLOSED CIRCULATION. NO SIGNIFICANT CHANGES ARE NEED TO
THE GOING FORECAST.
&&

.AVIATION...FOR MCCARRAN...SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED TO AFFECT THE MORMON MESA AND PEACH SPRINGS CORRIDORS
THROUGH MIDNIGHT BEFORE COVERAGE DIMINISHES LATE. WINDS ARE EXPECTED
TO REMAIN EASTERLY OVERNIGHT WITH SPEEDS RANGING FROM 8-14KTS.
CHANCES FOR THUNDERSTORMS WILL CONTINUE THROUGH MUCH OF THE WEEK.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...CHANCES FOR SHOWERS AND THUNDERSTORMS ARE EXPECTED
THROUGH THE WEEK...WITH THE GREATEST CHANCES NEAR AND SOUTHEAST OF
I-15. VERY HEAVY RAIN AND OUTFLOW WINDS WILL BE THE MAIN THREATS.
&&

.PREV DISCUSSION...
214 PM PDT MON JUL 30 2012

.SHORT TERM...SATELLITE LOOP SHOWED WELL DEFINED CIRCULATION OVER
THE FAR SOUTHERN CWA TRYING TO MOVE NORTH BUT BEING BLOCKED BY THE
BIG RIDGE OVER NORTHERN NEVADA. SURFACE OBS SHOWED HIGH DEWPOINTS
OVER THE SOUTHEAST HALF TO TWO THIRDS OF THE CWA...AND THE
COMBINATION OF THE TWO WAS FUELING THUNDERSTORMS WITH HEAVY RAIN
ROUGHLY SOUTHEAST OF I-15 EARLY THIS AFTERNOON. THESE STORMS WILL
GRADUALLY PROGRESS NORTHWEST THIS EVENING AND TONIGHT...THEN THE
DISTURBANCE IS EXPECTED TO STALL RIGHT OVER OUR CWA. THIS SHOULD
KEEP SIGNIFICANT FORCING IN PLAY FOR THE SOUTHEAST TWO THIRDS OF THE
AREA...WITH ONE HOPE FOR A REPRIEVE...IF IT RAINS LONG ENOUGH IN ONE
PLACE TO COMPLETELY OVERTURN THE AIRMASS THEN THAT AREA WOULD QUIET
DOWN FOR A DAY OR SO. SUCH CONVECTIVE SCALE PHENOMENA ARE NEARLY
IMPOSSIBLE TO FORECAST WITH ANY LEAD TIME...SO KEPT CHANCE TO LIKELY
POPS GOING OVER THE SOUTHEAST HALF OF THE CWA THROUGH THURSDAY. VERY
JUICY AIR WILL REMAIN IN PLACE...AND FLASH FLOODING WILL BE A
SIGNIFICANT THREAT WITH ANY SLOW MOVING THUNDERSTORMS. POINT
TEMPERATURES WILL BE HIGHLY DEPENDENT ON LOCATION AND TIMING OF
CONVECTION EACH DAY.

.LONG TERM...THE MODELS SHOW SOME HINT OF DRIER AIR TRYING TO PUSH
IN FROM THE SOUTHWEST OVER THE WEEKEND AS A SHORTWAVE TROUGH RIDES
AROUND THE PERIPHERY OF THE SOUTHERN PLAINS RIDGE. THIS SEEMS
PHYSICALLY REALISTIC...BUT TIMING SUCH FEATURES SEVERAL DAYS OUT IS
ALWAYS PROBLEMATIC. TWEAKED THE FORECAST A LITTLE BIT IN THAT
DIRECTION...BUT DID NOT JUMP ON IT. IF THE DRYING TREND
OCCURS...TEMPERATURES WOULD START AN UPWARD TREND AS WELL.
&&

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

UPDATE...ADAIR
AVIATION...GORELOW
PREV DISCUSSION...MORGAN

HTTP://WEATHER.GOV/LASVEGAS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LAS VEGAS NV
1042 AM PDT MON JUL 30 2012

AZZ001>003-036-CAZ524-526-527-NVZ016-020>022-310845-
NORTHWEST PLATEAU-LOWER COLORADO RIVER VALLEY-NORTHWEST DESERTS-
LAKE MEAD NATIONAL RECREATION AREA-EASTERN MOJAVE DESERT-
CADIZ BASIN-SAN BERNARDINO COUNTY-UPPER COLORADO RIVER VALLEY-
NORTHEAST CLARK COUNTY-LAS VEGAS VALLEY-SOUTHERN CLARK COUNTY-
1042 AM PDT MON JUL 30 2012 /1042 AM MST MON JUL 30 2012/

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH
THIS EVENING. HEAVY RAIN WILL BE POSSIBLE WITH STORMS AND A FLASH
FLOOD WATCH IS IN EFFECT FROM 9 AM THIS MORNING UNTIL 10 PM THIS
EVENING.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

MONSOON MOISTURE WILL LINGER THROUGH SUNDAY LEADING TO A CHANCE OF
MAINLY AFTERNOON AND EVENING THUNDERSTORMS. OVERALL THE HEAVY
RAINFALL POTENTIAL WITH STORMS WILL DECREASE THROUGH THE PERIOD.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY. SPOTTERS ARE ENCOURAGED
TO REPORT ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD
OPERATING PROCEDURES.

CAZ519>523-525-NVZ014-015-017>019-310845-
EASTERN SIERRA SLOPES-OWENS VALLEY-WHITE MOUNTAINS OF INYO COUNTY-
DEATH VALLEY NATIONAL PARK-WESTERN MOJAVE DESERT-MORONGO BASIN-
ESMERALDA AND CENTRAL NYE COUNTY-LINCOLN COUNTY-
WESTERN CLARK AND SOUTHERN NYE COUNTY-SHEEP RANGE-
SPRING MOUNTAINS-
1042 AM PDT MON JUL 30 2012

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

.DAY ONE...TODAY AND TONIGHT

MONSOON MOISTURE WILL CONTINUE TO INCREASE TOWARD THE NORTHWEST
LEADING TO A CHANCE OF MAINLY AFTERNOON AND EVENING THUNDERSTORMS
TODAY WITH LOCALLY HEAVY RAIN. ESMERALDA COUNTY AND NORTHERN INYO
COUNTY ARE EXPECTED TO REMAIN MAINLY DRY.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

MONSOON MOISTURE WILL LINGER THROUGH SUNDAY LEADING TO A CHANCE OF
MAINLY AFTERNOON AND EVENING THUNDERSTORMS...MAINLY OVER SOUTHEAST
NEVADA...EASTERN SAN BERNARDINO COUNTY AND MOHAVE COUNTY. OVERALL
THE HEAVY RAINFALL POTENTIAL WITH STORMS WILL DECREASE THROUGH
THE PERIOD.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. HOWEVER...
SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.