Winter Storm Watch 5, NWS Las Vegas, NV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
240 AM PST TUE FEB 16 2016

.SYNOPSIS...WARM SPRING LIKE CONDITIONS WILL CONTINUE THROUGH
WEDNESDAY BEFORE A PACIFIC STORM SYSTEM BRINGS INCREASING WINDS,
COOLER TEMPERATURES AND CHANCES FOR RAIN AND MOUNTAIN SNOW TO THE
AREA. DRY CONDITIONS RETURN FRIDAY INTO THE WEEKEND WITH A GRADUAL
WARMING TREND.
&&

.SHORT TERM...ALL IS QUIET FOR NOW WITH A BROAD HIGH PRESSURE RIDGE
FIRMLY ENTRENCHED ACROSS THE SOUTHWEST. THIS WILL MEAN ANOTHER DAY
OF VERY MILD WEATHER UNDER MOSTLY SUNNY SKIES. TEMPERATURES IN THE
LOWER REACHES OF DEATH VALLEY REACHED 90F MONDAY AND WILL MOST
LIKELY REACH ABOVE THAT AGAIN TODAY. TEMPERATURES AREA WIDE WILL BE
RUNNING 12 TO 18 DEGREES ABOVE NORMAL...AND RISE WITHIN A FEW
DEGREES OF MOST RECORDS BY LATE THIS AFTERNOON. MOST AREAS WILL
REMAIN WARM WEDNESDAY WITH AFTERNOON HIGHS PEAKING IN MANY AREAS DUE
TO ENHANCED MIXING FROM INCREASINGLY BREEZY SURFACE WINDS. LAS VEGAS
MAY BUMP UP TO 80 DEGREES...WITH CITIES ALONG THE RIVER APPROACHING
IF NOT EXCEEDING 90 DEGREES. FLY IN THE OINTMENT WILL BE INCREASING
CLOUDS MOVING IN DURING THE DAY...BUT WILL ERR ON THE WARM SIDE FOR
NOW GIVEN THE OVER PERFORMING HIGH TEMPERATURES AS OF LATE.

MEANWHILE...CHANGE IS ON THE WAY AS A LOW PRESSURE SYSTEM IS
CURRENTLY TAKING SHAPE OFF THE PACIFIC COAST AND WILL FLATTEN OUT
THE HIGH PRESSURE RIDGE WHICH WEVE BEEN BASKING UNDER THE PAST WEEK.
THIS STORM WILL BRING CHANCES FOR RAIN AND MOUNTAIN SNOW TO THE
REGION...AS WELL AS STRONG WINDS...AND COOLER TEMPERATURES.

SATELLITE IMAGERY INDICATES A NARROW TROPICAL TAP WITH THIS
APPROACHING SYSTEM REACHING BACK ALL THE WAY TOWARDS THE HAWAIIAN
ISLANDS. WHILE THE BEST DYNAMICS WILL REMAIN FURTHER NORTH ACROSS
THE GREAT BASIN...THE TROUGH WILL DRAG A WEAK COLD FRONT ACROSS THE
REGION WEDNESDAY EVENING INTO THURSDAY MORNING AND GIVEN THE DEGREE
OF THE MOISTURE AND ALSO FAIRLY SUBSTANCIAL INTEGRATED VAPOR
TRANSPORT...THINK A NARROW RIBBON OF LIGHT RAIN IS LIKELY AS THE
COLD FRONT PUSHES THROUGH. IVE RAISED POPS FOR MOST AREAS NORTH OF I-
40 TO ACCOUNT FOR THIS...AND I THINK FORECAST MODELS WILL BE
CATCHING UP ONCE THEY FULLY SAMPLE THE DEGREE OF MOISTURE CONTENT
AVAILABLE.

FURTHER WEST IN THE SIERRA...SIGNIFICANT PRECIPITATION IS LIKELY AS
MOISTURE PLUME CRASHES INTO THE SIERRA. SNOW LEVELS WILL BE STARTING
QUITE HIGH (ABOVE 8,000 FEET) BUT WILL FALL WEDNESDAY NIGHT TO BE
NEAR 5500 FEET SUNDAY MORNING. ABOVE THE 6000 FOOT LEVEL...5 TO 10
INCHES OF SNOW IS LIKELY...WITH A FOOT OR MORE ABOVE 8000 FEET AND A
WINTER STORM WATCH HAS BEEN POSTED TO ACCOUNT FOR THIS.

WIND WILL BE THE OTHER ITEM OF INTEREST WITH THIS UPCOMING
STORM...STRONG WINDS WITH GUSTS OVER 70 MPH ARE EXPECTED ALONG THE
SIERRA RIDGES. LOWER CONFIDENCE ON WINDS REACHING INTO THE OWENS
VALLEY AND HAVE OPTED NOT TO ISSUE ANY WIND HEADLINES AT THIS TIME.
THE INCREASING SATURATION OF THE AIRMASS HAS ME DOUBTING THE
LIKELIHOOD OF A WIND EVENT...AS WELL AS A LESS THAN FAVORABLE
STABILITY PROFILE AND MORE SOUTHERLY CROSS-BARRIER FLOW. IF WE DO
SEE STRONG WINDS REACHING INTO THE OWENS VALLEY...THINK IT WILL BE
THE SOUTHERN AREAS NEAR OLANCHA AND LONE PINE. WILL CONTINUE TO
MONITOR. STRONG WINDS LOOK LIKELY ALONG THE SPRING MOUNTAINS
ESPECIALLY NORTHEAST ASPECTS AND IVE GONE AHEAD AND ISSUED A HIGH
WIND WATCH FOR THAT AREA.

COOLER TEMPERATURES EXPECTED THURSDAY PUTTING OUR CURRENT 70+ DEGREE
DAY STRETCH IN LAS VEGAS IN JEOPARDY. DECREASING CLOUDS EXPECTED
THROUGH THE DAY THURSDAY INTO THURSDAY NIGHT WITH PRECIPITATION
CHANCES DIMINISHING BY SUNSET ACROSS THE AREA.

.LONG TERM...FRIDAY THROUGH TUESDAY.

A GENERALLY DRY AND TRANQUIL WEATHER PATTERN WILL RETURN FRIDAY
THROUGH EARLY NEXT WEEK. A FAST MOVING TROUGH IS FORECAST TO LIFT
INTO THE PACIFIC NORTHWEST FRIDAY AND BRUSH FAR NORTHERN CALIFORNIA.
THIS FEATURE WILL ACT TO STIR UP SOUTH TO SOUTHWEST BREEZES A LITTLE
ACROSS MOST OF THE FORECAST AREA FRIDAY...BUT SPEEDS SHOULD
GENERALLY BE IN THE 10-20 MPH RANGE AND IT APPEARS TO BE TOO FAR
NORTH TO PRODUCE STRONG DOWNSLOPE WINDS ON THE EAST SLOPES OF THE
SOUTHERN SIERRA.

A MEAN RIDGE IS THEN FORECAST TO BUILD OVER THE FORECAST AREA
THROUGH THE WEEKEND AND EARLY NEXT WEEK WHICH WILL PROVIDE MOSTLY
CLEAR SKIES AND A SLIGHT INCREASE IN TEMPERATURES. HIGH TEMPS WILL
RETURN TO THE MID 70S TO LOWER 80S ACROSS THE MOJAVE DESERT REGION
AND COLORADO RIVER VALLEY.

&&

.AVIATION...FOR MCCARRAN...WIND SPEEDS WILL GENERALLY BE LESS THAN 7
KNOTS TODAY AND TONIGHT WITH A LIGHT EASTERLY COMPONENT IN THE
AFTERNOON AND A SOUTHWEST COMPONENT OVERNIGHT UNDER ONLY SOME THIN
CIRRUS CLOUDS. GUSTY SOUTH-SOUTHWEST WILL DEVELOP WEDNESDAY
AFTERNOON AS A PACIFIC STORM APPROACHES THE WEST COAST.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...NORTHERLY BREEZES WILL CONTINUE ALONG THE COLORADO
RIVER VALLEY TODAY WITH GUSTS AROUND 25 KNOTS NEAR LAUGHLIN-BULLHEAD
CITY. LIGHT WINDS GENERALLY LESS THAN 10 KNOTS CAN BE EXPECTED
ELSEWHERE ACROSS THE REGION. SOUTH TO SOUTHWEST WINDS ARE EXPECTED
TO INCREASE ACROSS THE ENTIRE REGION BY WEDNESDAY AFTERNOON AS A
PACIFIC STORM APPROACHES THE WEST COAST.

&&

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

SHORT TERM/AVIATION...OUTLER
LONG TERM...ADAIR

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