Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 281054 CCA
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
254 AM PST SAT FEB 28 2015

.SYNOPSIS...A STORM SYSTEM WILL DROP SOUTH ACROSS CALIFORNIA TODAY
INTO TONIGHT RESULTING IN GUSTY WINDS AND POSSIBLE SHOWERS ACROSS
THE AREA. AS THE STORM DROPS OFF THE COAST OF SOUTHERN CALIFORNIA ON
SUNDAY IT WILL PUSH A BAND OF STEADIER PRECIPITATION INTO THE MOJAVE
DESERT THAT WILL LAST INTO SUNDAY NIGHT. ELSEWHERE ACROSS THE AREA
ON SUNDAY SHOWERS ARE POSSIBLE. UNSETTLED WEATHER WILL LAST ACROSS
THE AREA INTO TUESDAY NIGHT BEFORE A DRYING TREND TAKES PLACE.
&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT.

WE SHOULD SEE THE BOOKS CLOSE ON WHAT SHOULD GO DOWN AS THE WARMEST
FEBRUARY ON RECORD AND WARMEST METEOROLOGICAL WINTER ON RECORD IN
LAS VEGAS TODAY (AMAZINGLY BEATING OUT THE LATTER RECORD WHICH WAS
SET JUST LAST WINTER). A BROADLY DEFINED MID/UPPER LEVEL LOW CAN BE
NOTED THIS MORNING ON WATER VAPOR NEAR NORTHEAST CALIFORNIA. THIS
LOW IS EXPECTED TO TRACK SOUTH TODAY ACROSS THE GOLDEN STATE AND
HEAD TOWARD POINT CONCEPTION BY THIS EVENING. AS THE LOW TRACKS
CLOSER, IT SHOULD SPREAD SOMEWHAT BETTER MOISTURE AND MID-LEVEL
ENERGY INTO OUR AREA THAT SHOULD RESULT IN THE POTENTIAL FOR SHOWERS
MAINLY ACROSS THE NORTHERN HALF OF THE AREA. FURTHER SOUTH, IT
APPEARS MUCH OF THE MOJAVE DESERT SHOULD STAY DRY THROUGH EARLY THIS
AFTERNOON. A BIT BETTER MOISTURE AND FORCING MAKES IT CLOSER TO THE
MOJAVE DESERT THAT BY LATER THIS AFTERNOON, WE CANNOT RULE OUT A FEW
SHOWERS. THIS MAY BE THE CASE IF WE HIT THE CONVECTIVE TEMPERATURE
WHICH IS AROUND 60 TODAY FOR LAS VEGAS PER FORECAST SOUNDINGS. THE
GFS SHOWS SOME MINOR INSTABILITY AND CAPE OVER THE SOUTHERN GREAT
BASIN, BUT GIVEN WE DID SEE A FEW LIGHTNING STRIKES HERE FRIDAY
EVENING, ISOLATED THUNDERSTORMS WERE ADDED TO THE FORECAST FOR THIS
AFTERNOON AND EVENING FROM NORTHERN INYO COUNTY EAST TO LINCOLN
COUNTY. SNOW LEVELS WILL BE MAINLY 5000-6500 FEET TODAY.

AS THE LOW DROPS SOUTH, THIS WILL PLACE A NEARLY 100 KT JET STREAM
AT 250 MB ACROSS OUR AREA TODAY. WITH STRONG WINDS ALOFT AND A
DECENT ALIGNMENT OF THE WINDFIELDS WITH HEIGHT OVER THE MOJAVE
DESERT, THE HIGHER MOMENTUM ALOFT SHOULD GET MIXED DOWN TO THE
SURFACE AND PRODUCE WIND GUSTS OF 35-45 MPH WITH LOCAL GUSTS TO 50
MPH ACROSS MUCH OF THE SAN BERNARDINO COUNTY DESERTS AS WELL AS
SOUTHERN CLARK AND CENTRAL MOHAVE COUNTIES LATE THIS MORNING INTO
VERY EARLY THIS EVENING. AS A RESULT, I EXTENDED THE WIND ADVISORY
FOR NW SAN BERNARDINO COUNTY INTO EARLY THIS EVENING AND ALSO ADDED
A WIND ADVISORY FOR NORTHEAST SAN BERNARDINO COUNTY, THE MORONGO
BASIN, SOUTHERN CLARK COUNTY AND CENTRAL AND SOUTHERN MOHAVE COUNTY
AWAY FROM THE COLORADO RIVER. WINDS WILL DECREASE THIS EVENING AS
THE JET SINKS SOUTH AND THE UPPER SUPPORT WEAKENS.

TEMPS YESTERDAY WERE A TAD COOLER THAN I THOUGHT. HOWEVER, AS MUCH
AS I AM INCLINED TO GO TOWARD THE COLDER ECMWF FOR HIGHS TODAY, THE
LATEST OBSERVATIONS ARE NOT ALL THAT FAR OFF THOSE VALUES. EVEN
THOUGH WE ARE NOT GOING TO WARM UP MUCH, AREAS THAT DO NOT SEE
PRECIPITATION COULD STILL GET SOME SUN TODAY. THUS I WENT WITH A
BLEND OF THE MET AND MAV (WRF AND GFS NUMBERS) FOR HIGHS TODAY.

SHOWERS WILL LINGER ACROSS PARTS OF THE AREA INTO TONIGHT AS THE LOW
DROPS SOUTH OF POINT CONCEPTION AND SITS OFF THE COAST OF SOCAL.
THIS WILL HELP THE LOW TO TAP A PLUME OF SUBTROPICAL MOISTURE AND
FEED IT NORTH VIA THE JET ACROSS THE LOWER DESERTS OF SOCAL TOWARD
THE COLORADO RIVER VALLEY SUNDAY MORNING INTO SUNDAY NIGHT. THE
LATEST OPERATIONAL MODELS CONTINUE TO FAVOR A MORE WESTWARD
PLACEMENT OF THIS PLUME AND NOW SHIFT MORE OF IT INTO CLARK, LINCOLN
AND SAN BERNARDINO COUNTIES ESPECIALLY BY LATE SUNDAY AFTERNOON INTO
SUNDAY NIGHT. POPS WERE INCREASED TO ACCOUNT FOR THIS PLUME.
ELSEWHERE, SHOWERS WILL BE AROUND ON SUNDAY BUT BY SUNDAY NIGHT
START TO DECREASE AS THE COLD POOL ASSOCIATED WITH THE LOW CENTER
MOVES AWAY. THERE WILL BE A SHARP-CUT OFF WITH THIS BAND SO SOME
UNCERTAINTY EXISTS WITH THE WESTERN EDGE. HOWEVER, CONFIDENCE IS
HIGHER WITH POPS OVER MOHAVE COUNTY. THIS PLUME WILL HAVE A
SUBTROPICAL FETCH TO IT AND THUS BE VERY MOIST AND VERY WARM WITH
PWATS NEAR OR ABOVE 0.75 INCH. SNOW LEVELS WILL RISE FROM 4000-5000
FEET TO NEAR 6500 FEET WITHIN THE MAIN PRECIP BAND BY SUNDAY
AFTERNOON (HOWEVER, NORTH AND WEST THEY WILL REMAIN MUCH LOWER NEAR
5000 FEET). MODEL PROJECTIONS SHOW THE POTENTIAL FOR OVER AN INCH OF
LIQUID PRECIPITATION IN MOHAVE COUNTY ON SUNDAY INTO SUNDAY NIGHT
WHICH MAY RESULT IN MINOR FLOODING IN POOR DRAINAGE AREAS AS WELL AS
RAPID RISES ON WASHES. THE BEST CHANCE FOR RAIN IN LAS VEGAS WILL
COME LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT WITH THE CHANCE OF RAIN
BETTER ON THE EAST SIDE OF THE VALLEY AS THE MAIN PLUME OF MOISTURE
WILL BE AIMED CLOSER TO THIS AREA. HOWEVER, KEEP IN MIND THIS PLUME
STILL HAS THE POTENTIAL TO SHIFT. TEMPS ON SUNDAY WILL BE A FEW
DEGREES COLDER AS MARCH COMES IN LIKE A LION FOLLOWING OUR OVERALL
LAMB-LIKE WINTER.

.LONG TERM...MONDAY THROUGH FRIDAY.

NOT TOO MUCH CHANGE IN THINKING FOR THE UPCOMING WEEK. LOW PRESSURE
OVER SOUTHERN CALIFORNIA AT THE BEGINNING OF THE PERIOD WILL BE
REINFORCED/REPLACED BY ANOTHER SHORTWAVE TROUGH DIGGING DOWN THE
WEST COAST MONDAY AFTERNOON AND MONDAY NIGHT. MODELS HAVE TRENDED A
LITTLE FARTHER SOUTH AND WEST WITH THIS WAVE...WHICH MAY REDUCE
PRECIP CHANCES/AMOUNTS A LITTLE MONDAY AFTERNOON AND NIGHT. THE
TROUGH AXIS PASSES THROUGH THE CWA ON TUESDAY WITH PRECIP CHANCES
SHUTTING OFF TUESDAY NIGHT. DRY WEATHER IS THEN EXPECTED FOR
WEDNESDAY THROUGH FRIDAY. GUSTY NORTH WINDS ARE STILL LIKELY ON
WEDNESDAY...AND ADVISORIES MAY BE NEEDED IN THE FAVORED AREAS.
TEMPERATURES WILL REMAIN CHILLY THROUGH WEDNESDAY THEN START WARMING
UP ON THURSDAY.
&&

.AVIATION...FOR MCCARRAN...SOUTHWEST WINDS WILL INCREASE THIS
MORNING WITH SPEEDS BETWEEN 12-22 KTS AND POTENTIALLY GUSTING TO
AROUND 30 KTS BY THIS AFTERNOON. WINDS WILL DECREASE AROUND 03Z
SUNDAY TO 8-12 KTS. SCT-BKN CLOUDS AOA 10K FEET. THERE IS THE
POTENTIAL FOR STEADIER RAIN TO IMPACT THE LAS VEGAS VALLEY SUNDAY
AFTERNOON INTO SUNDAY NIGHT. CIGS BELOW 5K FEET AND REDUCED VSBY ARE
POSSIBLE THEN. MOUNTAIN OBSCURATIONS ARE LIKELY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...GUSTY WEST WINDS EXPECTED TODAY ACROSS SAN BERNARDINO,
SOUTHERN CLARK AND MOHAVE COUNTIES WITH SPEEDS BETWEEN 20-30 KTS.
SOME LOCATIONS...ESPECIALLY WESTERN SAN BERNARDINO COUNTY COULD
APPROACH 35 KTS. ELSEWHERE NORTH WINDS GENERALLY BETWEEN 8-12 KTS.
WIDESPREAD CIGS BELOW 5K ARE NOT EXPECTED...BUT MAY OCCUR IN HEAVIER
SHOWERS. SOME HIGHER PEAKS WILL LIKELY BECOME OBSCURED. THE BEST
CHANCE FOR SHRA AND ISOLATED TSRA WILL BE ALONG A LINE FROM KBIH TO
KCDC. STEADIER PRECIPITATION IS EXPECTED SUNDAY INTO SUNDAY NIGHT
ACROSS MOHAVE, CLARK, SAN BERNARDINO AND LINCOLN COUNTIES WITH CIGS
BELOW 5K FEET AND MVFR OR LOWER VSBY POSSIBLE.
&&

.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE REQUESTED TO REPORT
ANY SIGNIFICANT WEATHER ACCORDING TO STANDARD OPERATING PROCEDURES
TODAY THROUGH TUESDAY NIGHT.
&&

$$

SHORT TERM/AVIATION...STACHELSKI
LONG TERM...MORGAN

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