Area Forecast Discussion
Issued by NWS Las Vegas, NV

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000
FXUS65 KVEF 142230
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
230 PM PST SUN FEB 14 2016

.SYNOPSIS...WARM AND DRY WEATHER WILL CONTINUE THROUGH WEDNESDAY.
BREEZY NORTH WINDS WILL CONTINUE ACROSS THE LOWER COLORADO RIVER
VALLEY TOMORROW. A PACIFIC STORM SYSTEM WILL MOVE THROUGH THE REGION
LATE WEDNESDAY AND THURSDAY, BRINGING STRONG WINDS AND POTENTIALLY
SIGNIFICANT SNOW TO THE SOUTHERN SIERRA. CHANCES OF PRECIPITATION
WILL INCREASE ACROSS THE AREA ON THURSDAY, ESPECIALLY FOR THE
SOUTHERN GREAT BASIN. DRIER AND SLIGHTLY COOLER CONDITIONS ARE
EXPECTED FOR THE END OF THE WEEK.
&&

.SHORT TERM...THROUGH WEDNESDAY NIGHT.

2130Z WV IMAGERY INDICATES CONSIDERABLE UPPER-LEVEL MOISTURE
PROGRESSING SOUTHEASTWARD THROUGH THE GREAT BASIN AND THE
INTERMOUNTAIN WEST THIS AFTERNOON DOWNSTREAM OF A STRONG
ANTICYCLONIC JET ENTERING THE PACIFIC NORTHWEST. MID AND HIGH
CLOUDS ARE RAPIDLY MOVING THROUGH THE CWA THIS AFTERNOON, SLOWING THE
WARMING TREND IN NORTHERN AND CENTRAL PORTIONS OF THE AREA. IN
GENERAL, TEMPS ARE RUNNING ABOUT 2-4 DEGREES COOLER THAN YESTERDAY,
IN PART BECAUSE STRONGER NORTH WINDS HAVE NOT MIXED DOWN TO THE
SURFACE THANKS TO THE WEAKER INSOLATION. HOWEVER, MAY STILL SEE A
SMALL WINDOW OF STRONGER HEATING AND STRONGER WINDS LATE THIS
AFTERNOON AS THE THICKER CLOUDS CONTINUE SOUTHWARD. STRONGER NORTH
WINDS HAVE BEGUN IN THE LOWER COLORADO RIVER VALLEY, WITH BULLHEAD
CITY FREQUENTLY REPORTING GUSTS TO 35 MPH AND SUSTAINED WINDS
GREATER THAN 20 MPH AT COTTONWOOD COVE, NEEDLES, AND VIDAL JUNCTION.
THINKING THIS BODES WELL FOR THE LAKE WIND ADVISORY SET TO BEGIN
LATE TONIGHT, SO NO CHANGES WERE MADE AT THIS TIME. STRONGER WINDS
ARE ALSO DEVELOPING WESTWARD TO THE TWENTYNINE PALMS AREA, AND HI-
RES GUIDANCE SUGGESTS THIS WILL CONTINUE THROUGH TOMORROW. LOCAL
GUSTS APPROACHING WIND ADVISORY CRITERIA MAY OCCUR, BUT THINK THE
THREAT IS TOO LOW TO ISSUE ONE AT THIS TIME.

WEAK VORT LOBE IN NORTHERN CA WILL RACE THROUGH THE REGION OVERNIGHT
BRINGING ANOTHER ROUND OF HIGH CLOUDS, WHICH MAY KEEP TEMPS UP
OVERNIGHT. INCREASED SURFACE FLOW MAY ALSO KEEP THE SURFACE FAIRLY
MIXED. IN GENERAL, HAVE TEMPS ABOUT 2-5 DEGREES WARMER THAN LAST
NIGHT`S READINGS. CONTINUED TO TREND SNOW-COVERED VALLEYS OF
NORTHWEST LINCOLN AND CENTRAL NYE COUNTY WELL BELOW GUIDANCE
(THROUGH THE SHORT TERM).

HIGH-AMPLITUDE BUT PROGRESSIVE RIDGE BUILDS INTO THE WEST EARLY THIS
WEEK BRINGING CONTINUED WARM AND DRY CONDITIONS. WINDS SHOULD BEGIN
TO DECREASE AS THE SURFACE PRESSURE GRADIENT RELAXES BEGINNING
MONDAY NIGHT. HAVE A WARMING TREND OF ABOUT A DEGREE OR TWO PER DAY
THROUGH WEDNESDAY, BUT MIN TEMPS WERE FORECAST A BIT LOWER MONDAY
AND TUESDAY NIGHT AS THE WEAKER SURFACE WINDS AND ANTICIPATED MOSTLY
CLEAR SKIES WILL BE IDEAL FOR RADIATIONAL COOLING, PARTICULARLY IN
LOWER VALLEYS. WEDNESDAY HAS THE POTENTIAL TO BE VERY WARM AS
SOUTHWEST WINDS INCREASE AHEAD OF A SYSTEM APPROACHING THE AREA.

ON WEDNESDAY, A DECENTLY AMPLIFIED SHORTWAVE TROUGH APPROACHES THE
WEST COAST. A STRONG (100+ KT) SOUTHWESTERLY 500-MB JET STREAK WILL
INTERSECT THE SIERRA WEDNESDAY NIGHT. HI-RES MODELS ARE DEPICTING
WINDS REACHING HIGH WIND CRITERIA NEAR THE RIDGE TOPS BY WEDNESDAY
AFTERNOON. PATTERN RECOGNITION SUGGESTS STRONG DOWNSLOPING INTO THE
OWENS VALLEY IS POSSIBLE, AND FORECAST SOUNDINGS AT LEAST HINT AT
THE DEVELOPMENT OF A RIDGETOP INVERSION AND EVEN WEAK NEGATIVE
VERTICAL WIND SHEAR ATOP THE INVERSION WEDNESDAY NIGHT. THIS WILL
NEED TO BE WATCHED CLOSELY AS THE SYSTEM APPROACHES.

MODELS CONTINUE TO CONVERGE ON THE EVOLUTION OF THE TROUGH AS IT
APPROACHES THE AREA, WITH PRECIP BREAKING OUT IN THE SIERRA BY
WEDNESDAY EVENING. THOUGH THE DURATION IS SHORT, STRONG ASCENT
ASSOCIATED WITH JET DYNAMICS AND A MOISTURE SURGE WILL POSSIBLY
PRODUCE DECENT SNOW TOTALS IN THE HIGHER ELEVATIONS OF THE SIERRA.
SNOW LEVELS WILL BE QUITE HIGH TO BEGIN WITH (8000+ FEET) BUT WILL
RAPIDLY LOWER AS THE TROUGH AXIS APPROACHES. MODELS ALSO SHOWING
DECENT AGREEMENT ON PRECIP SPREADING INTO THE SOUTHERN SIERRA BY 12Z
THURSDAY, THOUGH CONSIDERABLE SHADOWING IS EXPECTED OWING TO THE
FAVORABLE ORIENTATION OF MIDLEVEL FLOW. INHERITED POPS LOOKED QUITE
GOOD AND ONLY MADE MINOR CHANGES THROUGH THE END OF THE SHORT TERM.

.LONG TERM...THURSDAY THROUGH SUNDAY.

AN UPPER LEVEL TROUGH PUSHES EASTWARD ACROSS CENTRAL CALIFORNIA AND
NEVADA THURSDAY WITH SHOWER CHANCES IN THE SIERRA AND THE SOUTHERN
GREAT BASIN...PRIMARILY DURING THE MORNING HOURS. THE ECMWF/GFS HAVE
THE TROUGH AXIS EAST OF THE AREA BY LATE THURSDAY AFTERNOON WITH
SHOWER ACTIVITY COMING TO AN END WHILE THE SLOWER GEM LINGERS
SHOWERS ACROSS THE SOUTHERN GREAT BASIN INTO THE EVENING. MODEL
PRECIP AMOUNTS RANGING FROM OF 0.10-0.33 INCHES ARE FORECAST
THURSDAY MORNING ACROSS THE HIGHER ELEVATIONS OF THE SOUTHERN SIERRA
WITH A TENTH OF AN INCH OR TWO...AT MOST...EAST OF THE SIERRA ACROSS
THE SOUTHERN GREAT BASIN.

DRY...ZONAL FLOW SETS UP FRIDAY AND SATURDAY WITH RIDGING BUILDING
BACK IN SUNDAY. TEMPERATURES THURSDAY THROUGH THE WEEKEND ARE
EXPECTED TO REMAIN 8-10 DEGREES ABOVE NORMAL.
&&

.AVIATION...FOR MCCARRAN...LIGHT AND VARIABLE WINDS ARE COMMON
ACROSS THE CENTRAL AND SOUTHERN VALLEY EARLY THIS AFTERNOON.
HOWEVER, COULD SEE A NORTH-NORTHWEST WIND THIS EVENING AT MCCARRAN,
GIVEN THE OVERALL FLOW ALOFT AND PRESENCE OF NORTHWEST WINDS ACROSS
THE NORTHERN VALLEY. WOULD THEN EXPECT LIGHT SOUTHWEST DRAINAGE TO
TAKE HOLD DURING THE EARLY MORNING HOURS MONDAY. WINDS SHOULD TEND
TO FAVOR A NORTHEASTERLY COMPONENT MONDAY AFTERNOON, YET CONFIDENCE
IS MODERATE BASED ON WHAT OCCURRED THIS AFTERNOON. OTHERWISE JUST
SOME PASSING HIGH CLOUDS EXPECTED.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...KIFP WILL CONTINUE TO SEE GUSTY NORTH WINDS THROUGH THE
NIGHT, ALTHOUGH SPEEDS SHOULD WEAKEN A BIT. WILL SEE A RETURN OF
STRONG NORTHERLY WINDS MONDAY FOR BOTH KIFP AND KEED, WITH SPEEDS
GUSTING TO AROUND 30 KNOTS OR SLIGHTLY BETTER NEAR KIFP. MOST OTHER
AREAS CAN EXPECT WINDS TO WEAKEN TONIGHT AND RANGE FROM 8-15 KNOTS
FROM THE NORTH-NORTHEAST ON MONDAY. OTHERWISE JUST SOME PASSING HIGH
CLOUDS EXPECTED.
&&

.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED.
PLEASE REPORT ANY SIGNIFICANT WEATHER ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&

$$

SHORT TERM...SHAFER
LONG TERM....SALMEN
AVIATION.....PADDOCK

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