FXUS65 KVEF 252220 CCA
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
221 PM PST WED NOV 25 2009

.SYNOPSIS...A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE AREA 
THROUGH THANKSGIVING DAY WITH MOSTLY CLEAR SKIES AND NEAR NORMAL 
TEMPERATURES. LOCALLY GUSTY WINDS WILL PERSIST DOWN THE COLORADO 
RIVER. A LOW PRESSURE SYSTEM WILL MOVE DOWN THE CALIFORNIA COAST 
OVER THE WEEKEND...BRINGING BREEZY CONDITIONS AND CHANCES FOR VALLEY 
RAIN AND MOUNTAIN SNOW.
&&

.SHORT TERM...SATELLITE SHOWS MOSTLY CLEAR SKIES AREAWIDE. SURFACE 
OBS SHOW LOCALLY GUSTY NORTH WINDS PERSISTING DOWN THE COLORADO 
RIVER VALLEY...ON THE BORDERLINE OF LAKE WIND ADVISORY CRITERIA FOR 
THE THIRD DAY IN A ROW. THE PRESSURE GRADIENT BETWEEN KELY AND KEED 
REMAINS MUCH TIGHTER THAN MODEL FORECASTS FROM THE PREVIOUS TWO 
DAYS. WITH THIS IN MIND...RAISED WINDS DOWN THE RIVER FROM MODEL 
OUTPUT AGAIN TOMORROW...ALTHOUGH SPEEDS SHOULD FINALLY START 
TRENDING DOWN AS HEIGHTS BEGIN TO FALL TO THE NORTH. SPEAKING OF 
FALLING HEIGHTS...THE MODELS HAVE COME INTO MUCH BETTER AGREEMENT 
WITH THE INCOMING PACIFIC TROUGH. THE TROUGH AXIS HITS THE NORTHERN 
CALIFORNIA COAST FRIDAY MORNING...THEN THE FLOW SPLITS WITH THE 
SOUTHERN END OF THE TROUGH FORMING A CLOSED LOW WHICH DIGS DOWN THE 
CALIFORNIA COAST TO SAN DIEGO BY SATURDAY AFTERNOON. THIS WILL BRING 
INCREASED PRECIP CHANCES TO THE SIERRA AND NEARBY MOUNTAINS FRIDAY 
NIGHT...AND SLIGHT CHANCES TO THE MOJAVE DESERT SATURDAY AND 
SATURDAY NIGHT. THE COLD FRONT WILL ALSO BE DELAYED UNTIL SATURDAY. 
GUSTY NORTH WINDS WILL BE POSSIBLE BEHIND THE FRONT...ESPECIALLY IF 
THE GFS SURFACE PRESSURE PATTERN VERIFIES BEST. WIND ADVISORIES MAY 
BE REQUIRED IN AREAS PRONE TO NORTH WINDS. TEMPERATURES WILL BE A 
CHALLENGE. THE NEW TRACK OF THE LOW IMPLIES LESS CHANCE OF SOUTHWEST 
WINDS IN THE LAS VEGAS VALLEY FRIDAY...THUS LOWERED HIGH TEMP 
FORECASTS A FEW MORE DEGREES. HEIGHTS WILL FALL SATURDAY AND CLOUDS 
SHOULD INCREASE AS WELL...BUT MANY AREAS WILL SEE THEIR BEST CHANCE 
OF INCREASED MIXING ON THE WARM SIDE OF THE FRONT ON SATURDAY AS 
WELL. CONFIDENCE IN TEMPERATURE FORECAST IS LOWER THAN AVERAGE.

.LONG TERM...THE UPPER LOW IS FORECAST TO PULL AWAY FROM THE AREA ON 
SUNDAY AFTERNOON...HOWEVER MODELS ARE ALL OVER THE PLACE IN THE 
PLACEMENT OF THE LOW BY THEN RANGING FROM CENTRAL ARIZONA ON THE 12Z 
ECMWF TO OFF THE COAST OF BAJA CALIFORNIA ON THE 12Z GFS AND 18Z 
DGEX. OVERALL EXPECT SOME DEGREE OF WRAP AROUND MOISTURE MAINLY IN 
THE MID LEVELS TO LINGER SUNDAY AFTERNOON ACROSS MOHAVE COUNTY AND 
POSSIBLY AS FAR WEST AS AN ESSEX TO CALIENTE LINE. ACROSS MOHAVE 
COUNTY THERE LOOKS TO ENOUGH MOISTURE TO SUPPORT THE CHANCE FOR A 
FEW SHOWERS WITH THE PRECIP MIXING WITH OR FALLING AS ALL SNOW OVER 
THE HIGHER ELEVATIONS NORTH AND EAST OF KINGMAN. ANYONE PLANNING TO 
TRAVEL SUNDAY ALONG I-40 SHOULD MONITOR THE LATEST FORECASTS. 
OTHERWISE 50-70 KTS OF WINDS ABOVE 500 MB OUT OF THE NORTHEAST SET 
UP ACROSS THE CWFA ON THE BACK SIDE OF THIS SYSTEM AND THIS WILL 
HELP TO GENERATE SOME RATHER BRISK WINDS THROUGH THE AFTERNOON 
ESPECIALLY IN SPOTS THAT FAVOR NORTHERLY TO NORTHEAST WINDS 
INCLUDING THE COLORADO RIVER VALLEY. THESE WINDS WILL BEGIN TO 
SUBSIDE SUNDAY NIGHT AS THE AFOREMENTIONED SYSTEM HEADS EASTWARD.

AN UPPER RIDGE BUILDS INTO THE REGION ON MONDAY FROM THE PACIFIC 
ALLOWING FOR WARMING TREND. AGAIN AS IS THE CASE THIS TIME OF YEAR 
INVERSIONS WILL TRAP LOW-LEVEL COLD AIR IN THE VALLEYS. SOME MINOR 
WARMING WILL OCCUR ON TUESDAY AS ANOTHER UPPER TROUGH APPROACHES 
FROM THE NORTH AND MAY MIX THINGS A LITTLE. THIS TROUGH WILL SWING 
BY ON WEDNESDAY PASSING BY THE REGION WITH JUST SOME HIGH CLOUDS BUT 
BRINGING BEHIND IT A REINFORCING SHOT OF COLDER AIR BY NEXT 
THURSDAY. WINDS WILL ALSO LIKELY BE ENHANCED FOR A WHILE ON 
WEDNESDAY AS THIS SYSTEM PASSES BY TO THE NORTHEAST.
&&

.AVIATION...FOR MCCARRAN...LIGHT WINDS FOLLOWING DIURNAL TRENDS ARE 
EXPECTED THROUGH TOMORROW AFTERNOON. CLEAR TONIGHT WITH CLOUDS 
GRADUALLY INCREASING ON FRIDAY AOA 25K FEET.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST 
CALIFORNIA...WINDS WILL BE MAINLY LIGHT AND FOLLOW DIURNAL 
DIRECTIONAL TRENDS THROUGH FRIDAY AFTERNOON. THERE MAY BE SOME GUSTS 
OF 15-20 KTS ACROSS THE SOUTHERN GREAT BASIN FRIDAY AFTERNOON OUT OF 
THE SOUTH AHEAD OF AN APPROACHING COLD FRONT. HIGH CLOUDS WILL 
INCREASE LATER TONIGHT AOA 25K FEET AND BE IN THE FEW-SCT RANGE ON 
FRIDAY.
&&

.CLIMATE...SO FAR THROUGH 2PM TODAY THE AVERAGE TEMPERATURE FOR THE 
NOVEMBER AT MCCARRAN INTERNATIONAL AIRPORT HAS BEEN 60.0 DEGREES. 
GIVEN THE CURRENT FORECASTED NUMBERS THERE IS SOME POTENTIAL FOR LAS 
VEGAS TO SEE THIS NOVEMBER RANK AMONG THE 10 WARMEST ON RECORD. THE 
WARMEST NOVEMBERS ON RECORD AT LAS VEGAS ARE...

1. 60.9 DEGREES IN 2007
2. 60.8 DEGREES IN 2008
3. 59.8 DEGREES IN 1995
4. 59.3 DEGREES IN 2005
5. 58.9 DEGREES IN 1949
6. 58.8 DEGREES IN 1999
7. 58.6 DEGREES IN 2001
8. 58.4 DEGREES IN 2006
9. 58.0 DEGREES IN 1976 AND 1981
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&

$$

MORGAN/STACHELSKI

HTTP://WEATHER.GOV/LASVEGAS