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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS65 KVEF 062322
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
322 PM PST FRI DEC 6 2013

.SYNOPSIS...
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A STORM SYSTEM WILL MOVE ACROSS THE AREA ON
SATURDAY...BRINGING STRONG WINDS TO THE WESTERN MOJAVE DESERT AND A
CHANCE OF SNOW AS LOW AS 2500 FEET IN SOUTHERN NEVADA AND NORTHWEST
ARIZONA. ANOTHER BLAST OF UNSEASONABLY COLD AIR WILL FOLLOW THIS
STORM...WITH BELOW FREEZING TEMPERATURES IN MANY LOWER DESERT AREAS
MONDAY AND TUESDAY MORNINGS. TEMPERATURES WILL WARM SLIGHTLY LATER
IN THE WEEK...BUT REMAIN SLIGHTLY BELOW NORMAL.
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&&

.SHORT TERM...
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THROUGH SATURDAY NIGHT. SATELLITE LOOP SHOWED CLOUDS
ALREADY INCREASING IN THE NORTHWEST CORNER OF THE CWA AHEAD OF THE
NEXT STORM SYSTEM DIGGING DOWN THE WEST COAST. THIS STORM WILL
QUICKLY SWING BY TOMORROW...BRINGING A BRIEF SHOT OF LOW ELEVATION
SNOW TO MUCH OF SOUTHERN NEVADA AND NORTHWEST ARIZONA AND STRONG
WINDS TO PARTS OF SAN BERNARDINO COUNTY AND THE EASTERN SIERRA
SLOPES. LEFT THE WINTER WEATHER ADVISORIES AS IS. LOW CONFIDENCE IN
SNOW AMOUNTS...BUT IMPACTS COULD BE GREATER THAN EXPECTED AS IT IS
EARLY IN THE SEASON AND THERE ARE LOTS OF OUTDOOR ACTIVITIES
SCHEDULED IN THE LAS VEGAS AREA. UPGRADED THE HIGH WIND WATCH FOR
NORTHWEST SAN BERNARDINO COUNTY TO A WARNING AS THE PATTERN SUPPORTS
WIND GUSTS OVER 50 KNOTS MAINLY NEAR AND NORTH OF BARSTOW /THANKS TO
HNX AND SGX FOR COORDINATION/. ALSO HOISTED A WIND ADVISORY FOR THE
MORONGO BASIN FOR THE SAME TIME FRAME. MOS GUIDANCE SUGGESTS A BRIEF
PERIOD OF PRE FRONTAL WIND GUSTS OVER 40 MPH...AND EXPERIENCE
SUGGESTS THAT SIMILAR POST FRONTAL WIND GUSTS ARE ALSO POSSIBLE
ALTHOUGH GUIDANCE DOES NOT SUPPORT IT. TOUGHEST CALL WAS THE EASTERN
SIERRA. THEY SHOULD SEE A BRIEF PERIOD OF HEAVY SNOW FOLLOWED BY
HIGH WINDS...WITH POTENTIAL FOR A SHORT LIVED DOWNSLOPE WIND EVENT.
DECIDED THE BEST COURSE OF ACTION WAS A WINTER STORM WARNING...NOT
FOR THE SNOW AMOUNTS BUT MAINLY FOR THE HIGH WINDS AND EXPECTED
BLOWING SNOW. PRECIP SHOULD BE COMING TO AN END FOR MOST OF THE AREA
BY SATURDAY EVENING AND THE WINDS SUBSIDING SATURDAY NIGHT AS THE
STORM SYSTEM MOVES EAST INTO UTAH.

.LONG TERM...SUNDAY THROUGH WEDNESDAY NIGHT.

ONCE THE AFOREMENTIONED SYSTEM DEPARTS FAR ENOUGH TO THE EAST BY
LATE SUNDAY MORNING ANY PRECIPITATION LEFT OVER EASTERN PORTIONS OF
MOHAVE COUNTY SHOULD COME TO AN END. OTHERWISE DRY AND VERY COLD
CONDITIONS ARE EXPECTED ACROSS THE AREA AS A POSITIVELY TILTED
TROUGH SETS UP ACROSS THE SOUTHWESTERN UNITED STATES FOR THE EARLY
PART OF NEXT WEEK. THE ECMWF CONTINUES TO BE COLDER THAN THE GFS
DURING THIS PERIOD BY A FEW DEGREES AND AT THIS TIME THE CURRENT
FORECAST SITS JUST BELOW A MEAN OF THE TWO WITH FORECAST TEMPS
LARGELY FOLLOWING THE CONS MODELS. MODEL FORECAST RELATIVE HUMIDITY
SHOWS A LOT OF DRY AIR ARRIVING BY SUNDAY AFTERNOON AND DOES NOT
BRING IN MUCH IN THE WAY OF ANY HIGH LEVEL MOISTURE THROUGH TUESDAY
NIGHT SO EXPECT CLEAR CONDITIONS IN THIS PERIOD. THE BIGGEST THING
THAT MAY HOLD UP TEMPS AT NIGHT WILL BE WIND - ESPECIALLY SUNDAY
NIGHT AND MONDAY NIGHT IN THE COLORADO RIVER VALLEY AS GUSTY NORTH
TO NORTHEAST SUSTAINED WINDS OF 15-25 MPH LINGER. HARD FREEZE
WARNINGS WILL LIKELY BE NEEDED FOR MOST OF THE LOWER MOJAVE DESERT
ELEVATIONS FOR SUNDAY NIGHT AND AGAIN ON MONDAY NIGHT AS 10-16 HOURS
OF AT OR BELOW FREEZING TEMPS WILL BE POSSIBLE. THE COLDER SPOTS IN
LINCOLN COUNTY WILL LIKELY BE SUBZERO AND GUIDANCE WAS UNDERCUT IN
THESE SPOTS. DAYTIME HIGHS SHOULD REMAIN ABOUT 14-18 DEGREES BELOW
NORMAL. WITH COLD AIR ADVECTION SHUT OFF BY MONDAY NIGHT AND
NORTHWEST FLOW ALOFT STARTING TO LESSEN IN STRENGTH TEMPS SHOULD NOT
BE AS COLD WITH READINGS UP BY 2-4 DEGREES FROM SUNDAY AND MONDAY
NIGHT.

RELIEF - IF YOU CAN CALL IT THAT - WILL START TO ARRIVE BY TUESDAY
AS A RIDGE ALOFT STARTS TO BUILD FROM THE WEST. THIS WILL RESULT IN
MODERATING TREND WITH HIGH TEMPS JUMPING UP BY 5-10 DEGREES. FURTHER
WARMING SHOULD TAKE PLACE ON WEDNESDAY WITH HIGHS JUMPING ANOTHER
3-5 DEGREES. ALTHOUGH READINGS WILL STILL BE BELOW NORMAL, IT WILL
ONLY BE ABOUT 5-8 DEGREES COMPARED TO THE 15+ DEGREES WE HAVE HAD
RECENTLY. SOME HIGH LEVEL CLOUDS MAY RETURN TO NORTHERN PORTIONS OF
THE AREA BY WEDNESDAY AFTERNOON. BY WEDNESDAY MORNING AND ESPECIALLY
THURSDAY MORNING, FREEZING TEMPS SHOULD BECOME MORE SPOTTY IN THE
LOWER MOJAVE DESERT ELEVATIONS AND THE NEED FOR ADDITIONAL FREEZE
PRODUCTS APPEARS UNLIKELY.

THURSDAY...MADE MINIMAL CHANGES TO THE FORECAST. ALL MODELS CONTINUE
TO INDICATE AN UPPER TROUGH MOVING ACROSS THE AREA LATE NEXT WEEK.
HOWEVER...THERE IS STILL DISAGREEMENT WITH THE TIMING AND EXACT
TRACK OF THE SYSTEM. WINDS WILL INCREASE THURSDAY INTO FRIDAY ACROSS
THE WESTERN HALF OF THE CWA. LEFT A CHANCE OF POPS IN THE GRIDS FOR
FRIDAY. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH NEXT WEEKEND.
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&&

.AVIATION...
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FOR MCCARRAN...LOWER CEILINGS WILL ARRIVE MID TO LATE
MORNING SATURDAY...WITH GUSTY SOUTHWEST WINDS AND A CHANCE OF RAIN
IN THE AFTERNOON. SNOW COULD MIX WITH THE RAIN...BUT ACCUMULATIONS
ARE UNLIKELY. DRY WEATHER WITH BREEZY NORTH WINDS AND COLD
TEMPERATURES CAN BE EXPECTED SUNDAY AND MONDAY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...A STORM SYSTEM WILL BRING LOWER CEILINGS AND CHANCES
FOR SNOW TO THE SIERRA NEVADA RANGE AND SOUTH CENTRAL NEVADA
SATURDAY MORNING...SPREADING TO SOUTHERN NEVADA AND NORTHWEST
ARIZONA SATURDAY AFTERNOON AND NIGHT. STRONG WINDS ARE EXPECTED ON
THE EASTERN SIERRA SLOPES IN THE AFTERNOON AND IN WESTERN SAN
BERNARDINO COUNTY IN THE AFTERNOON AND EVENING. DRY WEATHER WITH
BREEZY NORTH WINDS AND COLD TEMPERATURES CAN BE EXPECTED SUNDAY AND
MONDAY.
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&&

.VEF WATCHES/WARNINGS/ADVISORIES...
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NV...WINTER WEATHER ADVISORY FROM 10 AM TO 10 PM PST SATURDAY FOR
     NVZ016-018>020-022.
     WINTER WEATHER ADVISORY FROM 4 AM TO 10 PM PST SATURDAY FOR
     NVZ014-015-017.
AZ...WINTER WEATHER ADVISORY FROM 11 AM TO 11 PM MST SATURDAY FOR
     AZZ001-003.
CA...WINTER STORM WARNING FROM 4 AM TO 7 PM PST SATURDAY FOR CAZ519.
     WIND ADVISORY FROM 10 AM SATURDAY TO 3 AM PST SUNDAY FOR CAZ525.
     HIGH WIND WARNING FROM 10 AM SATURDAY TO 3 AM PST SUNDAY FOR
     CAZ523.
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&&

$$

MORGAN/STACHELSKI/STUMPF

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