Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 211001
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
300 AM PDT SUN APR 20 2014

.SYNOPSIS...WARM AND SOMEWHAT BREEZY CONDITIONS CAN BE EXPECTED
TODAY AS A LOW PRESSURE SYSTEM APPROACHES THE CALIFORNIA COAST. THIS
SYSTEM WILL MOVE ACROSS THE AREA TUESDAY BRINGING STRONG WINDS WITH
AREAS OF BLOWING DUST BUT MINIMAL PRECIPITATION CHANCES. A COOL DOWN
IS ALSO IN STORE WITH HIGH TEMPERATURES BY WEDNESDAY 10 TO 15
DEGREES COOLER THAN TODAY. AFTER A BRIEF WARMUP THURSDAY ANOTHER
SYSTEM WILL USHER IN COOLER TEMPERATURES AND GUSTY WINDS LATE WEEK.
&&

.SHORT TERM...THROUGH WEDNESDAY NIGHT...MODELS REMAIN CONSISTENT
WITH THE OVERALL PATTERN FOR THIS PERIOD. RIDGE AXIS SHIFTS EAST
TODAY AS A DEEPENING TROUGH APPROACHES THE COAST. HIGH CLOUDS WILL
GRADUALLY INCREASE THIS AFTERNOON FROM THE WEST. WINDS WILL ALSO
INCREASE WITH THE APPROACH OF THE TROUGH LEADING TO GOOD MIXING OF
THE AIR MASS AND THEREFORE ALLOWING TEMPERATURES TO WARM A BIT
COMPARED TO YESTERDAY. MUCH OF THE AREA WILL SEE SOMEWHAT BREEZY
SOUTH WINDS THIS AFTERNOON. HIGH CLOUDS WILL CONTINUE TO INCREASE
TONIGHT AS THE TROUGH MOVES TO THE CALIFORNIA COAST. WINDS SHOULD
DECREASE SOMEWHAT IN THE VALLEYS BUT BREEZY TO WINDY CONDITIONS ARE
EXPECTED AT THE HIGHER ELEVATIONS. AS THE TROUGH MOVES INTO NEVADA
TUESDAY WEST TO SOUTHWEST WINDS WILL BECOME RATHER STRONG AREA WIDE.
LATEST MODEL GUIDANCE INDICATES JUST ABOUT THE ENTIRE FORECAST AREA
WILL SEE ADVISORY LEVEL WINDS AND POTENTIAL FOR STRONG DOWNSLOPE
WINDS ON THE EASTERN SIERRA SLOPES DOWN INTO THE OWENS VALLEY. I
WENT AHEAD WITH A HIGH WIND WARNING FOR THE SIERRA AND OWENS VALLEY
AND WIND ADVISORY FOR ALL OTHER ZONES...ALL FROM 9 AM TO 9 PM. THERE
MAY BE SOME TIMING ISSUES BUT I DID NOT WANT TO TRY AND GET FANCY
AND RISK CONFUSION. FOR EXAMPLE...THE STRONGEST DOWNSLOPE WINDS
PROBABLY WILL NOT GET INTO THE OWENS VALLEY UNTIL SOMETIME IN THE
AFTERNOON BUT STRONG WINDS ARE EXPECTED IN THE SIERRA ALL DAY AND
EVENING. PRECIPITATION CHANCES THIS MODEL RUN LOOK EVEN SLIMMER THAN
BEFORE SO WE HAVE MINIMAL AREA IN THE NORTH WITH JUST A SLIGHT
CHANCE OF THUNDERSTORMS TUESDAY. THE TROUGH AXIS WILL SHIFT INTO
UTAH TUESDAY NIGHT WITH WINDS DECREASING AND BECOMING NORTHWESTERLY
OVER MOST OF THE AREA. ANY PRECIPITATION CHANCES WITH THIS TROUGH
WILL ALSO END BY EARLY TUESDAY EVENING.

.LONG TERM...WEDNESDAY THROUGH SUNDAY...SOMEWHAT CALMER CONDITIONS
ARE EXPECTED WEDNESDAY AND THURSDAY IN THE WAKE OF TUESDAY`S WIND
SYSTEM. SOME RESIDUAL NORTHERLY BREEZES ARE EXPECTED WEDNESDAY...BUT
ARE EXPECTED TO REMAIN WELL BELOW ADVISORY LEVELS. TEMPERATURES WILL
COOL TO JUST BELOW NORMAL BEFORE REBOUNDING THURSDAY UNDER A
TRANSIENT RIDGE OF HIGH PRESSURE.

THE NEXT TROUGH IS EXPECTED TO BEGIN IMPACTING THE REGION FRIDAY
WITH ANOTHER ROUND OF BREEZY TO WINDY CONDITIONS. THERE ARE STILL
CONSIDERABLE DIFFERENCES IN THE DETAILS OF THIS STORM WITH THE GFS
AND GEM FORMING A CLOSED CIRCULATION OVER THE FORECAST AREA LATE
FRIDAY AND SATURDAY WHILE THE ECMWF KEEPS AN OPEN WAVE THROUGHOUT.
IT APPEARS THAT THIS SYSTEM WILL HAVE AT LEAST A WEAK MOISTURE TAP
AND THUS WILL HAVE GREATER CHANCES FOR PRECIPITATION THAN TUESDAY`S
STORM...ESPECIALLY IF THE DYNAMICS OF THE LATEST GFS ARE INVOLVED.
FOR NOW HAVE WINDS INCREASING TO AROUND ADVISORY LEVELS ACROSS
PORTIONS OF THE AREA FRIDAY AND PRECIP CHANCES MAINLY NORTH OF AN
OLANCHA-LAS VEGAS-KINGMAN LINE FOR LATE FRIDAY THROUGH SATURDAY.
WILL BE INCLUDING AREAS OF BLOWING DUST FRIDAY WITH THIS MORNINGS
PACKAGE BUT WILL LEAVE OUT THE MENTION OF THUNDER AS CURRENT
INSTABILITY PROGS ARE FAIRLY WEAK...ESPECIALLY ON THE ECMWF. THE
WINDY CONDITIONS COULD ALSO BRING ANOTHER ROUND OF RED FLAG
CONDITIONS FRIDAY...THOUGH AT THIS POINT THE RH`S ARE MARGINAL AS
MOISTURE ADVECTS INTO THE REGION. WE WILL CONTINUE TO MONITOR THAT
POTENTIAL.

GENERAL CONSENSUS FROM SUNDAY ONWARD IS IMPROVING CONDITIONS AND THE
POSSIBILITY OF ANOTHER RIDGE BUILDING IN BY EARLY THE NEXT WEEK.
HOWEVER...IT`S STILL TOO EARLY TO HAVE MUCH CONFIDENCE IN THAT.
&&

.FIRE WEATHER...CONFIDENCE IS HIGH THAT MUCH OF THE AREA WILL SEE
WIND GUSTS OVER 35 MPH TUESDAY WITH RELATIVE HUMIDITY DIPPING BELOW
10 PERCENT IN MANY LOCATIONS. THE FIRE WEATHER WATCH WAS UPGRADED TO
A RED FLAG WARNING FROM 9 AM TO 9 PM TUESDAY. LATEST MODEL DATA
INDICATES STRONG WINDS WILL EXTEND UP TO ESMERALDA COUNTY SO ZONE
460 WAS ADDED TO THE WARNING.
&&

.AVIATION...FOR MCCARRAN...WINDS WILL GENERALLY BE OUT OF THE SOUTH
TODAY ALTHOUGH THERE COULD BE A PERIOD OF LIGHT EAST TO SOUTHEAST
WIND 15-19Z. BY NOON A SOUTH-SOUTHWEST WIND WILL STRENGTHEN WITH
SUSTAINED WINDS AROUND 15 KTS AND GUSTS AROUND 25 KTS. WINDS TONIGHT
SHOULD REMAIN SOUTH-SOUTHWEST 10-12 KTS BUT WILL INCREASE TO 20-30
KTS WITH GUSTS 35-40 KTS BY LATE TUESDAY MORNING...CONTINUING
THROUGH TUESDAY EVENING. CLEAR SKIES EARLY TODAY WILL GIVE WAY TO
INCREASING CIRRUS ABOVE 25 KFT THIS AFTERNOON AND TONIGHT.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...INCREASING SOUTH-SOUTHWEST WINDS TODAY WITH SUSTAINED
WINDS 15-20 KNOTS AND GUSTS 25-30 KNOTS THIS AFTERNOON. SOME
DECREASE IN WINDS TONIGHT IN THE VALLEY. WINDY ON TUESDAY WITH WEST
TO SOUTHWEST WINDS 20-30 KTS AND GUSTS 35-45 KTS. INCREASING CIRRUS
ABOVE 25 KFT TODAY AND TONIGHT.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...RED FLAG WARNING FROM 9 AM TO 9 PM PDT TUESDAY FOR NVZ460>466.
     WIND ADVISORY FROM 9 AM TO 9 PM PDT TUESDAY FOR NVZ014>022.
AZ...RED FLAG WARNING FROM 9 AM TO 9 PM MST TUESDAY FOR AZZ101-102.
     WIND ADVISORY FROM 9 AM TO 9 PM MST TUESDAY FOR AZZ001>003-036.
CA...RED FLAG WARNING FROM 9 AM TO 9 PM PDT TUESDAY FOR CAZ229.
     WIND ADVISORY FROM 9 AM TO 9 PM PDT TUESDAY FOR CAZ521>527.
     HIGH WIND WARNING FROM 9 AM TO 9 PM PDT TUESDAY FOR CAZ519-520.

&&

$$

HARRISON/WOLCOTT

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