Severe Thunderstorm Warning 136, NWS Las Vegas, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
947 AM PDT SUN SEP 11 2011

.SYNOPSIS...AN AREA OF LOW PRESSURE WILL REMAIN NEARLY STATIONARY
ALONG THE SOUTHERN CALIFORNIA COAST TODAY...BEFORE SLOWLY MOVING
INLAND WEDNESDAY AND THURSDAY. THERE WILL BE A CHANCE OF SHOWERS AND
THUNDERSTORMS EACH DAY...WITH SOME STORMS PERSISTING OVERNIGHT. THE
MAIN THREAT FROM THESE STORMS WILL BE LOCALLY HEAVY RAIN.
TEMPERATURES WILL STAY BELOW NORMAL THROUGH THURSDAY BEFORE
RETURNING CLOSER TO NORMAL FRIDAY AND SATURDAY.
&&

.UPDATE...SATELLITE SHOWS REMNANT MESOSCALE CONVECTIVE VORTEX
SPINNING NORTH ACROSS THE NORTHERN PORTION OF THE NEVADA NATIONAL
SECURITY SITE AND A SOUTHERLY MOISTURE FEED OVER EASTERN MOHAVE
COUNTY. IN BETWEEN WAS A HUGE DRY SLOT WITH MOSTLY CLEAR SKIES.
HOWEVER...THIS AREA REMAINS QUITE MOIST...AND SHOULD DESTABILIZE
QUICKLY WITH DAYTIME HEATING. THUS...CLOUDS ARE LIKELY TO FILL BACK
IN DURING THE DAY. CURRENT FORECAST REFLECTS THIS IDEA...AND NO
CHANGES PLANNED AT THIS TIME.
&&

.PREV DISCUSSION...
540 AM PDT SUN SEP 11 2011

.DISCUSSION...REMNANTS OF THE LINE OF ISOLATED SEVERE THUNDERSTORMS
THAT DEVELOPED OVER SAN BERNARDINO COUNTY LAST EVENING IS BECOMING
MORE STRATIFIED OVER INYO...NYE AND LINCOLN COUNTIES EARLY THIS
MORNING. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE
MOVING NORTHWEST AND DID INCREASE POPS ACROSS NORTHERN INYO AND
ESMERALDA COUNTIES FOR THE REST OF THE MORNING HOURS. ALSO INCLUDED
THE MENTION OF HAZE IN PARTS OF THE LOWER COLORADO RIVER AND
SOUTHERN MOHAVE COUNTIES ZONES AS WELL THIS MORNING DUE TO SUSPENDED
DUST PARTICLES PRODUCED BY AN OUTFLOW BOUNDARY FROM CENTRAL ARIZONA.

AN UPPER LOW WILL REMAIN STATIONARY ALONG THE SOUTHERN CALIFORNIA
COAST INTO TUESDAY BEFORE SLOWLY MOVING EAST INTO UTAH/ARIZONA ON
WEDNESDAY AND THURSDAY. NAM/GFS SUGGEST A MID-LEVEL DRY SLOT WORKING
AROUND THE LOW WILL LEAD TO LESS INSTABILITY ACROSS SOUTHWEST SAN
BERNARDINO COUNTY THIS AFTERNOON. ELSEWHERE...PLENTY OF MOISTURE AND
INSTABILITY ALONG WITH LIFT ASSOCIATED WITH A JETSTREAK SHIFTING
INTO SOUTHERN UTAH FOR THUNDERSTORMS TO REDEVELOP. DRY SLOT MAY LEAD
TO LESS THUNDERSTORM COVERAGE ON MONDAY...WITH AN UP DAY ON TUESDAY
AS MOISTURE RETURNS TO SOUTHERN CALIFORNIA. BELOW NORMAL
TEMPERATURES TODAY THROUGH TUESDAY.

THE THREAT OF SHOWERS/THUNDERSTORMS WILL CONTINUE ON WEDNESDAY AND
THURSDAY AS LOW OPENS UP AND SLOWLY MOVES EAST OVER THE MOJAVE
DESERT AND SOUTHERN GREAT BASIN. KEPT THE AREA DRY FRIDAY AND
SATURDAY UNDER WEAK RIDGING AS ANOTHER TROUGH NEAR THE CALIFORNIA
COAST.

.AVIATION...FOR MCCARRAN...LINGERING MOISTURE AND INSTABILITY MAY
BRING A SHRA/TSRA THE MOUNTAINS JUST SOUTH OF THE VALLEY THROUGH
MID-MORNING...HOWEVER GIVEN THE LOW ODDS OF SOMETHING RIGHT AT THE
AIRPORT WILL JUST KEEP A CB IN THE TAF. BY SUNDAY AFTERNOON AND
EVENING DRY AND STABLE AIR SHOULD BE IN PLACE AND THIS SHOULD
SUPPRESS ANY TSRA ACTIVITY OVER OR VERY CLOSE TO THE VALLEY. AS FOR
WINDS THEY SHOULD TREND TOWARDS TYPICAL DIURNAL DIRECTIONS THROUGH
THIS EVENING AT SPEEDS OF 10 KTS OR LESS...BUT ANY OUTFLOW
BOUNDARIES AROUND MAY RESULT IN GUSTY AND ERRATIC WINDS NOT
REPRESENTED IN THE TAF. MAINLY SCT CLOUDS AOA 8K-10K FEET THROUGH
SUNDAY EVENING. THE APPROACH CORRIDORS WILL SEE SCT SHRA/TSRA AROUND
THROUGH SUNDAY EVENING WITH THE LEAST COVERAGE IN THE DAGGETT
CORRIDOR.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SCT SHRA/TSRA WILL BE AROUND TODAY AND INTO THIS
EVENING MAINLY ACROSS THE INYO/ESMERALDA/LINCOLN/MOHAVE AND CENTRAL
NYE COUNTIES WITH LITTLE ACTIVITY OVER CLARK...SOUTHERN NYE AND THE
SAN BERNARDINO COUNTY DESERTS. THE MAIN THREATS IN AND NEAR
SHRA/TSRA WILL BE GUSTY AND ERRATIC WINDS AND REDUCED CIGS AND VSBY.
LOCAL AREAS OF BLDU AND HAZE WILL BE POSSIBLE IN MOHAVE AND EASTERN
SAN BERNARDINO AND FAR SOUTHEAST CLARK COUNTIES THIS MORNING ALONG
WITH REDUCED VSBY. OTHERWISE FEW-SCT CLOUDS AOA 8K-12K FEET THROUGH
TONIGHT. WINDS AWAY FROM TSRA OR ANY OUTFLOW BOUNDARIES SHOULD
FOLLOW TYPICAL DIURNAL DIRECTIONAL TRENDS AT 10 KTS OR LESS.
&&

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

MORGAN/PIERCE/STACHELSKI

HTTP://WEATHER.GOV/LASVEGAS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LAS VEGAS NV
605 AM PDT SUN SEP 11 2011

AZZ001>003-036-CAZ519>527-NVZ014>022-121000-
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-
605 AM PDT SUN SEP 11 2011 /605 AM MST SUN SEP 11 2011/

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

.DAY ONE...TODAY AND TONIGHT

AS THUNDERSTORMS REDEVELOP ACROSS THE AREA TODAY AND TONIGHT...HEAVY
RAIN...HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH
THE STRONGER THUNDERSTORMS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE WILL BE A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH
THURSDAY AS AN AREA OF LOW PRESSURE SLOWLY MOVES EAST OVER THE
MOJAVE DESERT AND SOUTHERN GREAT BASIN. LOCALLY HEAVY RAIN WILL
CONTINUE TO BE A THREAT. NO HAZARDOUS WEATHER IS EXPECTED ON
FRIDAY OR SATURDAY.

.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.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
235 PM PDT SUN SEP 11 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0229 PM     HAIL             4 NW SILVERADO RANCH    36.05N 115.19W
09/11/2011  E0.25 INCH       CLARK              NV   NWS EMPLOYEE

            PEA SIZED HAIL FELL FOR ABOUT FOUR MINUTES AT WFO LAS
            VEGAS. 0.18 INCHES OF RAIN FELL IN APPROXIMATELY TEN
            MINUTES.

&&

JGG