Area Forecast Discussion
Issued by NWS Las Vegas, NV

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000
FXUS65 KVEF 212215
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
215 PM PST SUN DEC 21 2014

.SYNOPSIS...A SYSTEM WILL PUSH THROUGH UTAH ON MONDAY INCREASING
NORTHERLY WINDS ACROSS THE AREA. A STRAY SHOWER WILL BE POSSIBLE
ACROSS NORTHERN LINCOLN COUNTY...OTHERWISE DRY CONDITIONS WITH HIGH
TEMPERATURES NEAR RECORD LEVELS ARE EXPECTED ON MONDAY. MILD WEATHER
WILL CONTINUE THROUGH CHRISTMAS EVE. ANOTHER SYSTEM WILL PASS ACROSS
THE AREA LATE CHRISTMAS EVE INTO CHRISTMAS DAY FOLLOWED BY COLDER
CONDITIONS ALONG WITH GUSTY WINDS FOR FRIDAY AND SATURDAY.
&&

.DISCUSSION...
THE BIG WEATHER STORIES FOR OUR AREA THIS WEEK WILL BE BREEZY NORTH
WINDS AND PERHAPS RECORD HIGH TEMPERATURES FOR SOME LOCATIONS
MONDAY. BREEZY NORTH WINDS WILL LINGER ALONG THE COLORADO RIVER
VALLEY TUESDAY. THEN A FRONTAL PASSAGE ON CHRISTMAS WILL BRING
ANOTHER COOL DOWN WITH BREEZY TO LOCALLY WINDY NORTH WINDS MAINLY
FRIDAY AND SATURDAY.

HIGH AND A FEW MID LEVEL CLOUDS CONTINUE TO STREAM ACROSS
REGION...CLOCKWISE AROUND HIGH PRESSURE JUST OFF THE CALIFORNIA
COAST. THIS AREA OF HIGH PRESSURE WILL EDGE EASTWARD INTO OUR AREA
FOR THE FIRST HALF OF THE WEEK. AT THE SAME TIME...SHORTWAVE ENERGY
WILL DROP SOUTHWARD THROUGH EASTERN UTAH AND EASTERN ARIZONA ON
MONDAY. THIS SHORTWAVE COMBINED WITH THE ADVANCING HIGH PRESSURE
WILL ENHANCE THE PRESSURE GRADIENT FOR US TOMORROW AND INTO TUESDAY.
LOCALLY WINDY CONDITIONS ARE EXPECTED ACROSS PORTIONS OF
ESMERALDA...NYE AND NORTHERN INYO COUNTIES MONDAY...BREEZY
CONDITIONS EXPECTED ELSEWHERE. THE BREEZY NORTH WINDS WILL HELP MIX
DOWN SOME WARMER AIR ALOFT AND THREATEN TO BREAK A FEW HIGH
TEMPERATURE RECORDS FOR THE 22ND OF DECEMBER /SEE CLIMATE SECTION
BELOW/. WE ARE CURRENTLY FORECASTING TEMPERATURES A DEGREE OR TWO
ABOVE RECORD VALUES FOR SOME LOCATIONS...INCLUDING LAS VEGAS...BUT
THAT MIGHT NOT BE WARM ENOUGH. 12Z NAM AND GFS SOUNDINGS SUGGEST 70
AND 72...RESPECTIVELY FOR A HIGH IN LAS VEGAS. STRONGER MIXING COULD
PUSH TEMPS TO THOSE VALUES.

BREEZY NORTH WINDS WILL CONTINUE TUESDAY...BUT MAINLY ALONG THE
COLORADO RIVER. WITH RIDGING HOLDING ALOFT...EXPECT TEMPERATURES TO
BE ABOUT 4-6 DEGREES ABOVE NORMAL AND MAY BE SLIGHTLY WARMER FOR
AREAS ALONG THE COLORADO RIVER...WITH THAT ADDED MIXING. NOT
EXPECTING MUCH CLOUD COVER TUESDAY...PERHAPS SOME INCREASING CIRRUS
AHEAD OF OUR NEXT SYSTEM. HOWEVER...THINK THIS WILL BE MORE LIKELY
WEDNESDAY. LIGHTER WINDS WEDNESDAY WILL MEAN SLIGHTLY COOLER HIGH
TEMPS...BUT STILL ABOVE NORMAL.

OUR FOCUS WILL THEN SHIFT TO A SHORTWAVE TROUGH APPROACHING THE
PACIFIC NORTHWEST WEDNESDAY NIGHT. THE 12Z GFS HAS DECIDED TO COME
IN SLIGHTLY LESS AMPLIFIED THAN IT`S PREVIOUS RUN...WHICH NOW
CONFLICTS MORE WITH THE ECMWF /SIMILAR TO A COUPLE DAYS AGO/.
HOWEVER...THE 12KM PARALLEL GFS HAS BEEN SHOWING A SLIGHTLY MORE
AMPLIFIED TROUGH FOR SEVERAL RUNS NOW...YET NOT QUITE AS AMPLIFIED
AS THE ECMWF. WILL SIDE WITH THE 12KM GFS...WHICH IS BASICALLY THE
MIDDLE ROAD AND ALIGNS MORE WITH WHAT THE 00Z OPERATIONAL GFS WAS
SHOWING. THIS REALLY DOES NOT CHANGE OUR ONGOING FORECAST MUCH AT
ALL. THE TROUGH SHOULD REACH THE PACIFIC NORTHWEST COAST WEDNESDAY
AFTERNOON...SWING THROUGH THE GREAT BASIN CHRISTMAS MORNING AND
REACH THE ROCKIES CHRISTMAS AFTERNOON. PRECIPITATION CHANCES FOR OUR
AREA STILL APPEAR MINIMAL...LIMITED TO JUST THE FAR NORTHERN
PORTIONS OF ESMERALDA THROUGH LINCOLN COUNTIES. TEMPERATURES WILL
TREND COOLER TO ROUND OUT THE WEEK AND INTO THE WEEKEND...RANGING
FROM GENERALLY 30S/40S NORTHERN AREAS TO 50S/60S SOUTHERN AREAS FOR
HIGHS. WITH THE PASSAGE OF THIS FRONT...EXPECT NORTHERLY WINDS TO
INCREASE...PARTICULARLY FRIDAY AND SATURDAY AS HIGH PRESSURE
SQUEEZES IN AND ENHANCES THE PRESSURE GRADIENT.
&&

.AVIATION...FOR MCCARRAN...VARIABLE WINDS AT 5 KTS OR LESS ARE
EXPECTED THROUGH 03Z MONDAY BEFORE SOUTHWEST WINDS AT 5-10 KTS
RETURN...SIMILAR TO LAST NIGHT. WIND SPEEDS SHOULD START TO INCREASE
MONDAY MORNING FROM THE WEST-SOUTHWEST BEFORE TRANSITIONING TO
NORTH-NORTHWEST FOR THE AFTERNOON. THIS COULD CAUSE RUNWAY
CONFIGURATION ISSUES EARLY IN THE DAY. CLOUDS WILL TREND TOWARD THE
FEW-SCT RANGE MONDAY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WINDS WILL TREND TOWARD TYPICAL DIURNAL DIRECTIONS
THROUGH TONIGHT. WINDS WILL INCREASE FROM THE NORTH MONDAY WITH
GUSTS OF 25-30 KNOTS POSSIBLE FOR KBIH...LIGHTER ELSEWHERE. CIGS
MAINLY SCT-BKN CLOUDS AOA 15K FEET TRENDING TOWARD FEW-SCT LATE
TONIGHT INTO MONDAY.
&&

.CLIMATE...HIGH TEMPERATURES WILL BE CLOSE TO RECORD LEVELS FOR SOME
LOCATIONS ON MONDAY...PARTICULARLY LAS VEGAS. HERE ARE SOME RECORD
HIGHS FOR DECEMBER 22.

LAS VEGAS          68/1950
DESERT ROCK        69/1985
MT CHARLESTON      56/2005
BISHOP             71/2000
BARSTOW-DAGGETT    78/1955
DEATH VALLEY       82/1914
NEEDLES            74/1955
KINGMAN            72/1906
&&

.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED.
&&

$$

DISCUSSION/AVIATION/CLIMATE...PADDOCK

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