Area Forecast Discussion
Issued by NWS Las Vegas, NV

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000
FXUS65 KVEF 231035
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
335 AM PDT WED APR 23 2014

.SYNOPSIS...LIGHTER WINDS AND COOLER TEMPERATURES CAN BE EXPECTED
TODAY UNDER A NORTHWEST FLOW ALOFT. TEMPERATURES WILL WARM UP AGAIN
FOR THURSDAY BEFORE ANOTHER LOW PRESSURE SYSTEM BRINGS IN EVEN
COOLER TEMPERATURES...GUSTY WINDS AND CHANCES FOR RAIN AND MOUNTAIN
SNOW FRIDAY INTO SATURDAY.
&&

.SHORT TERM...THROUGH THURSDAY NIGHT...THE TROUGH RESPONSIBLE FOR
THE STRONG WINDS ON TUESDAY IS EXITING TO THE EAST TODAY LEAVING A
MOSTLY DRY NORTHWEST FLOW ALOFT OVER THE AREA. THERE WILL SOME HIGH
CLOUDS HOWEVER...ESPECIALLY ACROSS THE NORTH. THE FIRST BATCH OF
HIGH CLOUDS WILL EXIT TO THE EAST THIS MORNING BUT ANOTHER BATCH
WILL COME IN FROM THE NORTHWEST THIS AFTERNOON. WINDS HAVE DIED DOWN
CONSIDERABLY BUT THERE COULD STILL BE SOME LOCALLY BREEZY NORTH
WINDS TODAY...MAINLY DOWN THE COLORADO RIVER VALLEY BELOW DAVIS DAM
MID MORNING TO EARLY AFTERNOON. A WESTERLY FLOW WILL BE OVER THE
AREA TONIGHT THROUGH THURSDAY WITH SOME HIGH CLOUDS AT TIMES.
TEMPERATURES THURSDAY WILL WARM UP BACK TO SEVERAL DEGREES ABOVE
NORMAL. INCREASING SOUTHWEST FLOW ALOFT WILL DEVELOP THURSDAY NIGHT
AS ANOTHER TROUGH DROPS TO JUST OFF THE NORTHERN CALIFORNIA COAST.
WINDS WILL START TO PICK UP AT THE HIGHER ELEVATIONS...ESPECIALLY
NEAR THE SIERRA CREST. HIGH LEVEL CLOUDS WILL BE INCREASING OVER THE
AREA AND THERE MAY BE JUST ENOUGH MID LEVEL MOISTURE INCREASE FOR A
SLIGHT CHANCE OF SHOWERS OVER THE SIERRA.

.LONG TERM...FRIDAY THROUGH TUESDAY...A FEW CHANGES AND ADDED
DETAILS FOR THE FRIDAY AND SATURDAY FORECAST. OVER THE PAST 48 HOURS
MODELS HAVE TRENDED TOWARDS A DEEPER AND MORE DYNAMIC SYSTEM FOR THE
FRIDAY/SATURDAY PERIOD AND THE LATEST GUIDANCE IS NO DIFFERENT. BOTH
THE 00Z GFS AND ECMWF ARE IN GOOD AGREEMENT THAT THE TROUGH AXIS
WILL BE CROSSING THE WEST COAST AROUND 00Z SATURDAY. AS THE TROUGH
APPROACHES THE COAST FRIDAY WIDESPREAD ADVISORY LEVEL WINDS ARE
EXPECTED TO DEVELOP...VERY SIMILAR TO YESTERDAY`S EVENT. WINDS DO
APPEAR TO TRAVEL A BIT FURTHER SOUTH THAN TODAY`S SYSTEM BUT THE
MAGNITUDE APPEARS TO BE SIMILAR. ONCE AGAIN HAVE MENTIONED AREAS OF
BLOWING DUST FOR AREAS WITH NEAR-ADVISORY LEVEL WINDS. SOME LIGHT
SHOWERS AND EVEN AN ISOLATED THUNDERSTORM WILL BE POSSIBLE OVER THE
SIERRA AND FAR NORTHERN ZONES PRIOR TO 00Z SATURDAY. FIRE WEATHER
CONDITIONS ARE A BIT MORE MUDDLED WITH RH`S HOVERING NEAR CRITICAL
LEVELS.

AFTER 00Z SATURDAY PRECIPITATION CHANCES WILL SPREAD TO THE
SOUTHEAST AND COULD AFFECT THE ENTIRE FORECAST AREA BY EARLY
SATURDAY MORNING. AS WE`VE DISCUSSED FOR THE LAST FEW DAYS...THE
AVAILABLE MOISTURE WITH THIS SYSTEM IS NOT ALL THAT IMPRESSIVE.
HOWEVER...WITH THE AMOUNT OF DYNAMIC FORCING CURRENTLY PROGGED
THERE`S A GOOD CHANCE THAT SHOWERS WILL BE WIDESPREAD. AS A RESULT I
HAVE INCREASED POPS WITH THIS MORNINGS PACKAGE...MENTIONING AT LEAST
A SLIGHT CHANCE AREAWIDE. BY 12Z SATURDAY THE 500MB LOW CENTER
SHOULD BE MAKING IT`S WAY INTO THE FORECAST AREA...WITH THE BEST
DYNAMICS AND SLIGHTLY BETTER MOISTURE CONVERGENCE DEVELOPING ALONG
THE EASTERN MOHAVE COUNTY BORDER. THIS IS WHERE THE BEST CHANCES OF
SIGNIFICANT PRECIPITATION WILL BE POSSIBLE. I`VE ALSO INTRODUCED THE
MENTION OF THUNDER...MAINLY NORTH AND EAST OF LAS VEGAS AS MODELS
HAVE COME INTO MUCH BETTER AGREEMENT ON THE PLACEMENT OF
INSTABILITY. AS THE TROUGH CONTINUES TO MOVE EAST SATURDAY
PRECIPITATION WILL TAPER OFF FROM WEST TO EAST AND SHOULD BE LARGELY
FINISHED BY EARLY SUNDAY MORNING. A FIRST STAB AT STORM TOTAL
PRECIPITATION AMOUNTS GIVES A SOUTHWEST TO NORTHEAST ORIENTED
GRADIENT...WITH LESS THAN 0.05 INCH OVER SAN BERNARDINO COUNTY...TO
NEAR 0.5 INCH OVER NORTHERN MOHAVE COUNTY AND THE HIGHER ELEVATIONS
OF LINCOLN COUNTY. THE SIERRA MAY ALSO PICK UP UPWARDS OF A HALF
INCH NEAR THE CREST. NOTE THAT THESE ARE PRELIMINARY NUMBERS
AND WILL BE REFINED AS WE GET CLOSER. SNOW LEVELS ARE FORECAST TO
DROP TO AROUND 5500 FEET BY SATURDAY MORNING...SO SOME MOUNTAIN
LOCATIONS ARE LIKELY TO SEE SOME FALLING SNOW. SIGNIFICANT
ACCUMULATIONS ARE NOT CURRENTLY EXPECTED DUE TO BOTH LIMITED
MOISTURE AND THE WARM GROUND TEMPERATURES. THE BEST CHANCE FOR ANY
SIGNIFICANT ACCUMULATION WILL BE NEAR THE SIERRA CREST (MAINLY ABOVE
8-9K FEET). AS YOU`D EXPECT TEMPERATURES WILL ALSO PLUMMET TO 10-14
DEGREES BELOW NORMAL BY SATURDAY...TRANSLATING TO TEMPERATURES IN
THE UPPER 60S FOR LAS VEGAS.

FOR SUNDAY AND BEYOND...NORTHERLY BREEZES WILL CONTINUE IN THE WAKE
OF THE SYSTEM...BUT OTHERWISE MUCH CALMER CONDITIONS ARE EXPECTED AS
HIGH PRESSURE BUILD OVER THE REGION. SUNDAY WILL ALSO MARK THE
BEGINNING OF A WARMING TREND THAT SHOULD BRING TEMPERATURES BACK TO
NEAR NORMAL BY MONDAY OR TUESDAY.
&&

.AVIATION...FOR MCCARRAN...WINDS SHOULD BE FROM THE NORTH/NORTHWEST
10-15 KTS THROUGH ABOUT 18Z TODAY THEN VEER AROUND TO THE NORTHEAST
5-8 KTS. TYPICAL DRAINAGE SOUTH/SOUTHWEST WINDS TONIGHT. NO
OPERATIONALLY SIGNIFICANT CLOUDS ARE EXPECTED THROUGH THURSDAY.
ANOTHER ROUND OF VERY STRONG SOUTHWEST WINDS IS LIKELY ON FRIDAY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...MOST AREAS WILL HAVE NORTHERLY WINDS TODAY 5-15 KTS.
SUSTAINED 15-20 KTS WITH GUSTS UP TO 30 KTS ARE POSSIBLE DOWN THE
COLORADO RIVER VALLEY FROM ABOUT 16Z TO 21Z TODAY. TYPICAL DIURNALLY
DRIVEN WINDS TONIGHT THEN MAINLY SOUTH WINDS THURSDAY 5-15 KTS.
VARIABLE HIGH CLOUDS AOA 20KFT THROUGH THURSDAY. ANOTHER ROUND OF
VERY STRONG SOUTHWEST WINDS IS LIKELY ON FRIDAY.
&&

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

$$

HARRISON/WOLCOTT

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