Flash Flood Warning 53, NWS Las Vegas, NV

000
WGUS75 KVEF 082121
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
221 PM PDT FRI AUG 8 2008

AZC015-082200-
/O.CON.KVEF.FF.W.0053.000000T0000Z-080808T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MOHAVE AZ-
221 PM MST FRI AUG 8 2008

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 300 PM MST FOR NORTH
CENTRAL MOHAVE COUNTY...

AT 212 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A THUNDERSTORM PRODUCING VERY HEAVY RAIN OVER THE GRAND 
WASH CLIFFS...OR ABOUT 6 MILES WEST OF MOUNT LOGAN. DOPPLER RADAR 
HAS ESTIMATED OVER 3 INCHES OF RAIN HAS FALLEN IN THE PAST HOUR AND 
A HALF. 

THIS THUNDERSTORM WITH EXCESSIVE RAIN WILL OTHERWISE REMAIN OVER
MAINLY RURAL AREAS OF THE INDICATED COUNTY.

FLOODING IS OCCURRING OR IS IMMINENT. IT IS IMPORTANT TO KNOW WHERE
YOU ARE RELATIVE TO STREAMS...RIVERS...OR CREEKS WHICH CAN BECOME
KILLERS IN HEAVY RAINS. CAMPERS AND HIKERS SHOULD AVOID STREAMS OR
CREEKS.

IN DESERT TERRAIN THERE ARE HUNDREDS OF LOW WATER CROSSINGS WHICH ARE
POTENTIALLY DANGEROUS IN HEAVY RAIN. DO NOT ATTEMPT TO TRAVEL ACROSS
FLOODED ROADS. FIND ALTERNATE ROUTES. SEVERAL INCHES OF SWIFTLY
FLOWING WATER CAN CARRY VEHICLES AWAY.

LAT...LON 3655 11352 3656 11330 3629 11328 3627 11351

$$

ASG

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1026 AM PDT FRI AUG 8 2008

.SYNOPSIS...MOIST AND UNSTABLE AIR WILL REMAIN OVER PORTIONS OF
SOUTHERN NEVADA...NORTHWEST ARIZONA AND EASTERN SAN BERNARDINO
COUNTY IN SOUTHEAST CALIFORNIA THROUGH SATURDAY RESULTING IN
ISOLATED TO SCATTERED THUNDERSTORMS. A DRIER SOUTHWEST FLOW IS
FORECAST TO DEVELOP BY THE LATTER PART OF THE WEEKEND AND CONTINUE
INTO EARLY NEXT WEEK WITH THUNDERSTORMS CONFINED TO PRIMARILY
NORTHWEST ARIZONA.
&&

.UPDATE...CURRENT THERMODYNAMIC ANALYSIS FROM SPC INDICATED QUITE A
BIT OF CAPE AND LOW LIFTED INDEX OVER EASTERN SAN BERNARDINO COUNTY.
NAM12 ALSO INDICATES A FAIR AMOUNT OF MOISTURE AND INSTABILITY THERE
AS WELL. UPDATED TO INCREASE POPS OVER EASTERN SAN BERNARDINO
COUNTY. OTHERWISE FORECAST LOOKS GOOD WITH DRY AND STABLE AIR ACROSS
MUCH OF THE WESTERN PORTION OF THE FORECAST AREA.
&&

.AVIATION...FOR MCCARRAN...WINDS WILL RANGE IN DIRECTION FROM SOUTH
TO SOUTHEAST TODAY WITH SPEEDS GENERALLY FROM 8-10 KTS AND
OCCASIONALLY GUSTING TO 20 KTS IN THE AFTERNOON. CLOUD COVERAGE WILL
INCREASE AS CUMULUS DEVELOPS THROUGH THE LATE MORNING AND AFTERNOON.
ISOLATED THUNDERSTORMS ARE POSSIBLE AROUND THE LAS VEGAS VALLEY BUT
GREATER COVERAGE EXPECTED SOUTH AND EAST OF THE AIRPORT. AT THE
AIRPORT ITSELF...THE PRIMARY THREAT TODAY WILL BE GUSTY...ERRATIC
WINDS FROM THUNDERSTORM OUTFLOW BOUNDARIES. AFFECTED APPROACH
CORRIDORS TODAY ARE PEACH SPRINGS...MORMON MESA AND DAGGETT.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SCATTERED THUNDERSTORM COVERAGE EXPECTED MAINLY EAST OF
LAS VEGAS BUT SCATTERED STORMS COULD ALSO FORM OVER EASTERN SAN
BERNARDINO COUNTY AS FAR WEST AS KDAG. ONLY A SLIGHT CHANCE OF
STORMS OVER THE NORTHWEST FORECAST AREA. PRIMARY THREATS CONTINUE TO
BE HEAVY RAIN AND GUSTY...ERRATIC WINDS. THE GREATEST CLOUD COVERAGE
WILL BE OVER THE EASTERN HALF OF THE AREA. SURFACE WINDS GUSTING TO
25 KTS IN SOME AREAS TODAY.
&&

.PREV DISCUSSION...350 AM PDT FRI AUG 8...SHORT TERM...CONSIDERABLE
DEBRIS CLOUDS OVER THE EASTERN HALF OF THE CWA WITH BASICALLY CLEAR
SKIES OVER THE WESTERN HALF. ALTHOUGH CONVECTION HAS
ENDED...ISOLATED ACTIVITY POSSIBLE EARLY THIS MORNING ACROSS MAINLY
EASTERN SAN BERNARDINO/MOHAVE COUNTIES THUS WILL NOT MENTION LATE
MORNING START OF CONVECT IN THESE ZONES.  SLOW INCREASE IN SOUTHWEST
FLOW ALOFT TO CONTINUE TO DRY THE WESTERN PORTION OF THE CWA TODAY
INTO THE WEEKEND WITH DRYING SLOWLY TAKING PLACE OVER THE EASTERN
PORTION. HOWEVER...FOR TODAY BEST DYNAMICS/ INSTABILITY REMAINS OVER
LINCOLN/CLARK/MOHAVE AND THE EASTERN PORTION OF SAN BERNARDINO
COUNTY...FOR ISOLATED/SCATTERED AFTERNOON/EVENING THUNDERSTORMS. THE
POSSIBILITY OF HEAVY RAIN CONTINUES AS PW VALUES REMAIN AROUND 1.5
INCHES. MAIN CONCERN THOUGH IS DEBRIS CLOUDS WILL INHIBIT INITIAL
HEATING AND THUS WILL LOOK FOR INITIAL CONVECTION TO BE AROUND THE
EDGES OF THE CURRENT CLOUD COVER. WITH INCREASING SOUTHWEST FLOW
ALOFT...DRYING AS MENTIONED TO BEGIN TO MOVE OVER THE EASTERN
PORTION ON SATURDAY WITH CONVECTION MAINLY OVER THE EASTERN PORTION
OF LINCOLN/CLARK/MOHAVE COUNTIES AND THEN FOR SUNDAY...MAINLY MOHAVE
COUNTY. TEMPERATURES TO BE NEAR TO SLIGHTLY BELOW NORMAL THROUGH THE
WEEKEND...DEPENDING ON THE LOCATIONS OF THE AFTERNOON
CLOUDS/THUNDERSTORMS.

.LONG TERM...IN THE WAKE OF A TROUGH AXIS THAT SWINGS ACROSS THE PAC
NW AND NORCAL/NORTHERN NEVADA ON SUNDAY NIGHT/MONDAY MORNING HEIGHTS
WILL BEGIN TO REBOUND ACROSS THE WESTERN CONUS ON MONDAY. WE SHOULD
STILL SEE ENOUGH OF A DRY WEST FLOW ALOFT ACROSS THE CWFA AND THUS
THEY ONLY MOISTURE/INSTABILITY THAT SUPPORTS KEEPING IN ANY POPS IS
ACROSS MOHAVE COUNTY AND EVEN HERE WE MAY JUST SEE SOME CUMULUS
BUILD UPS AT BEST. ALTHOUGH THE ECMWF RAPIDLY TRIES TO REBUILD THE
WESTERN CONUS RIDGE BY MONDAY AFTERNOON...THE GEM AND THE GFS
ENSEMBLE MEAN DELAY THIS UNTIL TUESDAY. THE OPERATIONAL GFS KEEPS
HEIGHTS MUCH FLATTER ON THE 6Z RUN. GIVEN THE MODELS ARE INSISTING
IN BRINGING A COLD FRONT AS FAR SOUTH AS FLORIDA IN AUGUST...ONE
WOULD HAVE TO THINK THE UPPER LEVEL PATTERN IN THE WEST WOULD
SUPPORT A HIGHLY AMPLIFIED RIDGE. THUS HAVE LEANED TOWARDS THE
GEM/GFS ENSEMBLES/ECMWF FOR THE LONG RANGE. THIS WOULD SUPPORT 500
MB HEIGHTS AT/ABOVE 588 DM...WHICH WOULD SUPPORT HIGHS AT LEAST 2 TO
4 DEGREES ABOVE NORMAL. JUST HOW QUICK ANY MONSOONAL MOISTURE
RETURNS IS STILL QUESTIONABLE...BUT A RETURN NORTHWARD OF MOISTURE
LOOKS POSSIBLE BY THURSDAY...WHICH WILL ONCE AGAIN BRING BACK THE
PROSPECTS FOR CONVECTION TO MUCH OF THE AREA.
&&

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

HARRISON/SALMEN/JENSEN/STACHELSKI

HTTP://WEATHER.GOV/LASVEGAS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LAS VEGAS NV
557 AM PDT FRI AUG 8 2008

AZZ001>003-036-CAZ519>527-NVZ014>022-090400-
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-
557 AM PDT FRI AUG 8 2008 /557 AM MST FRI AUG 8 2008/

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

.DAY ONE...TODAY AND TONIGHT

MOIST AND UNSTABLE AIR WILL LEAD TO ISOLATED TO SCATTERED
THUNDERSTORMS...MAINLY DURING THE AFTERNOON AND EVENING.
THUNDERSTORMS CAPABLE OF PRODUCING LOCALLY HEAVY RAIN CAN BE
EXPECTED OVER GENERALLY THE SAME AREA AS THURSDAY...MAINLY
SOUTHEAST NEVADA AND NORTHWEST ARIZONA. THE PRIMARY THREAT WILL BE
ISOLATED FLASH FLOODING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THUNDERSTORM COVERAGE DIMINISHES FROM WEST TO EAST SATURDAY INTO
SUNDAY AS DRIER SOUTHWEST FLOW DEVELOPS. HOWEVER A SLIGHT CHANCE
OF THUNDERSTORMS WILL CONTINUE OVER NORTHWEST ARIZONA THROUGH
THURSDAY.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.