Severe Thunderstorm Warning 17, NWS Las Vegas, NV

383 
WWUS55 KVEF 032052
SVSVEF

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
152 PM PDT SUN AUG 3 2014

CAC071-032115-
/O.CON.KVEF.SV.W.0017.000000T0000Z-140803T2115Z/
SAN BERNARDINO CA-
152 PM PDT SUN AUG 3 2014

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 215 PM PDT
FOR EXTREME EAST CENTRAL SAN BERNARDINO COUNTY...

AT 145 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A SEVERE THUNDERSTORM. THIS STORM WAS LOCATED OVER EXTREME 
EAST CENTRAL SAN BERNARDINO COUNTY...OR 17 MILES WEST OF LAKE HAVASU 
CITY...MOVING NORTH AT 10 MPH.

LOCATIONS IMPACTED INCLUDE...
HIGHWAY 62 BETWEEN MILE MARKERS 24 AND 40.

LAT...LON 3442 11457 3437 11466 3458 11476 3459 11454
TIME...MOT...LOC 2051Z 169DEG 10KT 3450 11463

$$

STACHELSKI

778 
WWUS55 KVEF 032117
SVSVEF

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
217 PM PDT SUN AUG 3 2014

CAC071-032127-
/O.EXP.KVEF.SV.W.0017.000000T0000Z-140803T2115Z/
SAN BERNARDINO CA-
217 PM PDT SUN AUG 3 2014

...THE SEVERE THUNDERSTORM WARNING FOR EXTREME EAST CENTRAL SAN
BERNARDINO COUNTY HAS EXPIRED...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS WEAKENED AND MOVED 
AWAY FROM HIGHWAY 95.

LAT...LON 3442 11457 3437 11466 3458 11476 3459 11454
TIME...MOT...LOC 2052Z 169DEG 10KT 3450 11463

$$

STACHELSKI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
1007 AM PDT SUN AUG 3 2014

.SYNOPSIS...INCREASING THUNDERSTORM COVERAGE WITH A RISK OF HEAVY
RAIN CAN BE EXPECTED TODAY AS DEEPER MOISTURE AND A STRONG UPPER
LEVEL DISTURBANCE MOVE IN FROM THE SOUTH. THIS WILL BE FOLLOWED BY A
DRYING TREND FROM SOUTHWEST TO NORTHEAST EARLY IN THE UPCOMING WEEK.
&&

.UPDATE...
LIGHT TO MODERATE SHOWERS ARE PIVOTING AROUND THE UPPER LOW CENTERED
OVER SOUTHWEST CALIFORNIA. A BAND STRETCHING FROM DIAMOND RANCH TO
SEARCHLIGHT TO MOUNTAIN PASS TO DUMONT DUNES WILL CONTINUE TO LIFT
NORTH...WITH CLEARING NOTED ALONG THE LOWER COLORADO RIVER VALLEY
FROM LAKE HAVASU CITY SOUTHWARD. ANOTHER VORT MAX IS STARTING TO
ROUND THE UPPER LOW OVER THE NORTHERN BAJA PENINSULA. THIS WILL
INCREASE SHEAR ALONG THE LOWER COLORADO RIVER VALLEY FROM YUMA TO
BLYTHE WITHIN AN ALREADY DESTABILIZING ENVIRONMENT. CONVECTION
SHOULD DEVELOP ACROSS THAT AREA...WHICH COULD CONTAIN STRONGER
WINDS...THIS AFTERNOON BEFORE SLIDING NORTHWARD GENERALLY ALONG THE
LOWER COLORADO RIVER VALLEY. CONVECTION COULD BE STRONG ACROSS
SOUTHERN MOHAVE AND EASTERN SAN BERNARDINO COUNTIES BEFORE WEAKENING
AS IT CONTINUES NORTH. THIS MEANS GENERALLY A LATER START OF
CONVECTION FOR OUR AREA. HOWEVER...WITH THE VORT MAX MOVING DIRECTLY
OVER THE FORECAST AREA OVERNIGHT...THE CHANCE OF SHOWERS AND STORMS
WILL CONTINUE YET LIFT NORTH.

MADE A FEW ADJUSTMENTS TO THE POP AND WEATHER TRENDS OVER THE NEXT
FEW HOURS. NOT SEEING ANY LIGHTNING AT THIS TIME...SO HAVE CUT BACK
ON THUNDER WORDING. HAVE RAMPED UP THUNDER WORDING THROUGH THE
AFTERNOON AS WE WILL GRADUALLY DESTABILIZE THROUGH THE DAY FROM
SOUTH TO NORTH. OUR NORTHERN CWA REMAINS A QUESTION MARK AS TO
WHETHER IT WILL DESTABILIZE ENOUGH FOR SOME HEAVIER CONVECTION...BUT
THE 4KM NAM DEPICTS PERHAPS AN ENHANCED BAND OF CONVECTION THIS
EVENING IN THE NORTH. GIVEN THERE IS SOME POTENTIAL FOR
ENHANCEMENT...WILL KEEP THE FLASH FLOOD WATCH AS IS.
&&

.AVIATION...FOR MCCARRAN...THE MAIN CHALLENGE THROUGH MONDAY MORNING
WILL BE TIMING ON ANY PERIODS OF RAIN OR TSRA AND HOW LOW CIGS AND
VSBY GET. GENERALLY CIGS SHOULD STAY BETWEEN 7K AND 10K FEET BUT
COULD LOWER IN ANY STEADIER OR HEAVIER PERIODS OF RAIN OR TSRA
ANOTHER 1-2K FEET. VSBY SHOULD MAINLY STAY VFR. WINDS WILL TREND
TOWARD TYPICAL DIURNAL DIRECTIONS AT 10 KTS OR LESS - HOWEVER - ANY
OUTFLOW BOUNDARIES OR SHRA/TSRA COULD CAUSE GUSTY AND ERRATIC WIND
SHIFTS. ONE CONCERN FOR THE PERIOD BETWEEN 01Z AND 04Z MONDAY WILL
BE THE POTENTIAL FOR A BRIEF PERIOD OF GUSTY EAST TO SOUTHEAST WINDS
SHOWN BY HIGH RESOLUTION LOCAL MODELS THAT APPEARS TO BE SOME SORT
OF OUTFLOW BOUNDARY. MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH
MONDAY MORNING. SHRA/TSRA WILL BE AROUND AS WELL IN ALL APPROACH
CORRIDORS.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...PERIODS OF RAIN WITH ISOLATED TSRA ARE EXPECTED THROUGH
THIS AFTERNOON ACROSS THE AREA. BETWEEN 22Z TODAY AND 03Z MONDAY
SHRA/TSRA SHOULD DEVELOP ACROSS THE SOUTHEASTERN PORTION OF THE AREA
AND MOVE NORTHWEST TO NORTH. THIS ACTIVITY SHOULD BE CAPABLE OF
CONTAINING STRONGER STORMS AND THUS A HIGHER CHANCE TO TRIGGER GUSTY
AND ERRATIC WINDS AND POTENTIALLY BLDU REDUCING VSBY. OTHERWISE
EXPECT CIGS TO MAINLY BE BETWEEN 7 AND 10K FEET LOWERING ANOTHER
1-2K FEET IN RAIN OR TSRA ANOTHER 1-2K FEET WITH VSBY GENERALLY VFR.
LOCAL MOUNTAIN OBSCURATIONS ARE EXPECTED THROUGH MONDAY MORNING.
&&

.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION MAY BE NEEDED
TODAY FOR THUNDERSTORMS WITH VERY HEAVY RAIN AND POTENTIAL FLASH
FLOODING. ISOLATED STRONG WINDS FROM CONVECTION ARE ALSO POSSIBLE
ACROSS SOUTHERN MOHAVE AND EASTERN SAN BERNARDINO COUNTIES.
&&

.PREVIOUS DISCUSSION...
222 AM PDT SUN AUG 3 2014

.SHORT TERM...SATELLITE LOOP SHOWED MAIN CIRCULATION CENTER NEAR
ENSENADA EARLY THIS MORNING AND MOVING NORTH. SHOWERS AND
THUNDERSTORMS WERE MOVING WEST TO NORTHWEST ACROSS MUCH OF THE CWA
EARLY THIS MORNING...WITH RAIN AMOUNTS MOSTLY LIGHT THUS FAR.
COMBINATION OF VERY HIGH PRECIPITABLE WATER /AS MUCH AS TWO INCHES
IN THE FAR SOUTHERN CWA/ AND FORCING ASSOCIATED WITH THE UPPER LOW
STILL JUSTIFIES THE FLASH FLOOD WATCH. DRIER AIR WILL START TO WORK
INTO THE SOUTHWEST CWA MONDAY AS THE UPPER LOW BEGINS TO LIFT NORTH
OF THE AREA...BUT PRECIP CHANCES WILL REMAIN IN PLACE FOR THE
NORTHEAST THREE QUARTERS OF THE REGION. THE DRIER AIR MAKES MORE
EASTWARD PROGRESS ON TUESDAY...BUT ANY LINGERING STORMS COULD BE
STRONG AS STRONGER UPPER LEVEL WINDS COME INTO PLAY.

.LONG TERM...WEDNESDAY THROUGH SATURDAY...THE MEDIUM RANGE MODELS
CONTINUE TO INDICATE A DRY SOUTHWEST FLOW ALOFT STRENGTHENING OVER
THE REGION WEDNESDAY AND THURSDAY AS THE AXIS OF A BROAD TROUGH
GRADUALLY LIFTS FROM CALIFORNIA ACROSS THE GREAT BASIN. AT FIRST
GLANCE...THIS APPEARS TO BE A DRY PATTERN BUT A CLOSER LOOK AT GFS
AND ECMWF SFC-700 MB WINDS DO NOT INDICATE A REAL STRONG SCOURING
SOUTHWESTERLY COMPONENT. THE CONCERN IS THAT THE DEEP MOISTURE
CURRENTLY IN PLACE MAY BE SLOWER TO EXIT THAN INDICATED BY THE
MODELS AND THE LATEST ECMWF ACTUALLY KEEPS 8-12 DEGREE 850 MB
DEWPOINTS IN PLACE OVER SOUTHERN NEVADA WEDNESDAY WHILE MID LEVELS
DRY OUT. THE NAM AND GFS DEPICT CONSIDERABLY DRIER LOW LEVELS
WEDNESDAY. THOUGH NO SIGNIFICANT CHANGES TO THE FORECAST WERE
MADE...WILL KEEP A 15 PERCENT POP IN THE SPRING MOUNTAINS/SHEEP
RANGE WEDNESDAY AND THURSDAY WITH 15-25 POPS IN THE ARC FROM
NORTHERN INYO COUNTY ACROSS SOUTH CENTRAL NEVADA AND NORTHWEST
ARIZONA. THE 60-70 KNOT JET AND CONSIDERABLE SHEER PROFILE EVIDENT
FROM FORECAST SOUNDINGS WEDNESDAY WOULD FAVOR WELL ORGANIZED STORMS
WITH A TENDENCY TO BECOME SEVERE IF ENOUGH MOISTURE REMAINS...SO IT
IS WORTH KEEPING IN MIND OVER THE NEXT FEW DAYS.

THE ECMWF INDICATES ADDITIONAL MOISTURE PUSHING UP ACROSS WESTERN
ARIZONA FRIDAY THROUGH THE WEEKEND AS A CLOSED HIGH SETS UP OVER NEW
MEXICO AND AND THE SOUTHERN ROCKIES A WEAK TROUGH HANGS ALONG THE
WEST COAST. POPS WERE INCREASED A LITTLE FOR MOHAVE COUNTY
ACCORDINGLY. THE TROUGH OVER THE REGION WEDNESDAY AND THURSDAY
SHOULD KEEP TEMPERATURES A FEW DEGREES BELOW NORMAL AND HIGHS WERE
NUDGED DOWN SLIGHTLY THOSE DAYS BASED ON THE LATEST ECMWF/GFS
BC GUIDANCE.
&&

UPDATE...PADDOCK
AVIATION...STACHELSKI
SHORT TERM...MORGAN
LONG TERM...ADAIR

FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:

HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER