FXUS65 KVEF 300411
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
810 PM PST SUN NOV 29 2009

.SYNOPSIS...THE AREA WILL BE UNDER WEAK RIDGING THROUGH MUCH OF THE 
WEEK RESULTING IN MOSTLY CLEAR CONDITIONS AND ABOVE NORMAL 
TEMPERATURES. GUSTY NORTH WINDS ARE EXPECTED ALONG THE COLORADO 
RIVER VALLEY ON MONDAY WITH RELATIVELY LIGHT NORTH TO NORTHEAST 
WINDS ELSEWHERE.
&&

.UPDATE...GENERALLY CLOUD FREE SKIES ACROSS THE CWA THIS EVENING AS 
THE UPPER LOW CONTINUES TO SLOWLY SHIFT OUT OF THE AREA AND THE 
BANDS OF MOISTURE WRAPPING AROUND THE LOW SHIFT TO THE SOUTH WITH 
THE LOW. NORTHERLY SURFACE GRADIENTS REMAIN A CONCERN...HOWEVER MOST 
STATIONS HAVE OR ARE DECOUPLING WITH THE FLOW ALOFT SO WINDS SHOULD 
REMAIN AROUND 10KTS OR LOWER OVERNIGHT. SURFACE GRADIENTS AND FLOW 
ALOFT TO BE ON THE DECREASE ON MONDAY RESULTING IN LESS NORTH WINDS 
THAN TODAY...EXCEPTION BEING ALONG THE COLORADO RIVER VALLEY WHERE 
LOCAL GUSTY WINDS EXPECTED. OVERALL SHORT TERM FORECAST ON TRACK AND 
DO NOT PLAN ON ANY UPDATES THIS EVENING.
&&

.AVIATION...FOR MCCARRAN...WINDS EXPECTED TO BE LESS THAN 10KTS 
THROUGH 06Z TUESDAY WITH MOSTLY CLEAR SKIES.  

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST 
CALIFORNIA...AREA WINDS WILL REMAIN NORTHERLY 5-10KTS THROUGH 
TONIGHT WITH LIGHT NORTH WINDS ON MONDAY. THE EXCEPTION WILL BE THE 
COLORADO RIVER VALLEY WHICH WILL SEE LOCAL GUSTS TO AROUND 20KTS 
THROUGH MUCH OF MONDAY. SKIES TO BE MOSTLY CLEAR THROUGH 06Z 
TUESDAY.
&&

.PREV DISCUSSION...236 PM PST SUN SHORT TERM...NO BIG SHORT TERM 
ISSUES THROUGH WEDNESDAY WITH THE POTENT UPPER LOW MOVING OFF TO THE 
EAST AND HIGH PRESSURE TAKING OVER. THE ONLY LINGERING ISSUE WILL BE 
GUSTY NORTH WINDS ALONG THE COLORADO RIVER VALLEY ON MONDAY. 
OTHERWISE...HIGH TEMPERATURES TODAY WERE SEVERAL DEGREES WARMER THAN 
EXPECTED SO ONE WOULD EXPECT SIMILAR TEMPERATURES FOR THE NEXT 
COUPLE OF DAYS...IE...ABOVE NORMAL. HOWEVER WITH A COOLER MORNING 
LOW FORECAST FOR MONDAY AND TUESDAY...LIGHTER WINDS COULD LEAD TO 
LESS MIXING AND TEMPS TOPPING OUT JUST RIGHT AROUND NORMAL. OPTED TO 
NUDGE TOWARDS GUIDANCE WHICH MEANT INCREASING TEMPS A COUPLE OF 
DEGREES. SKIES SHOULD CLEAR OVERNIGHT AND THERE COULD POSSIBLY BE 
SOME LINGERING CU IN MOHAVE COUNTY TOMORROW BUT THAT SHOULD BE ABOUT 
IT. A WEAK LOW MOVES THROUGH THE EASTERN PACIFIC AND APPROACHES THE 
WEST COAST MID WEEK. THIS COULD BRING AN INCREASE IN HIGH CLOUDS BUT 
IT LOOKS LIKE LITTLE ELSE AT THIS POINT.

.LONG TERM...IT IS HARD TO PUT ANY TRUST IN THE MODELS IN THE LONGER 
RANGE GIVEN THE DRAMATIC FLIPS SEEN OVER THE PAST FEW DAYS HOWEVER 
THERE APPEARS TO AT LEAST BE SOME GENERAL CONSENSUS FOR THE THURSDAY 
AFTERNOON THROUGH SATURDAY AFTERNOON PERIOD. AN UPPER RIDGE BUILDS 
EASTWARD INTO CALIFORNIA ON THURSDAY AFTERNOON AND IS FORECAST TO 
THEN SHIFT EASTWARD ACROSS THE SOUTHWESTERN U.S. BY SATURDAY 
AFTERNOON AND FLATTEN OUT. GIVEN THE RISE IN HEIGHTS AND WARMING 
ALOFT I HAVE WARMED UP HIGHS A TAD WHICH PUTS THEM A FEW DEGREES 
ABOVE NORMAL. WEAK MIXING IN THE LOW-LEVELS ALONG WITH VALLEY 
INVERSIONS AND MODEL FLIP-FLOPPING THOUGH HAVE LED ME TO UNDERCUT 
NUMBERS A FEW DEGREES FOR EACH AFTERNOON FROM THURSDAY THROUGH 
SATURDAY. THE BEST WARMING SHOULD BE IN THE HIGHER ELEVATIONS WHICH 
ARE ABOVE THE INVERSION HEIGHT.

ONCE WE GET TO SUNDAY THINGS GET INTERESTING AND DOWNRIGHT TOUGH TO 
CALL. AN UPPER TROUGH APPROACHES FROM THE NORTH...BREAKING DOWN THE 
RIDGE. EXPECT THE ABUNDANT SUNSHINE OF THE LATER PART OF THE WEEK TO 
BE REPLACED BY PLENTIFUL CLOUDS AND WINDS TO LIKELY GET ENHANCED TO 
SOME EXTENT AS SYSTEMS GET CLOSER TO THE AREA. AFTER THE FIRST UPPER 
TROUGH MOVES THROUGH SATURDAY NIGHT...SOLUTIONS REALLY DIVERGE WITH 
THE 00Z GEM/12Z OPERATIONAL GFS/18Z DGEX ALL SHOWING A BIG UPPER LOW 
DROPPING SOUTHWARD WHILE THE ECMWF KEEPS THE AREA IN A WESTERLY FLOW 
AND BRINGS INTO THE PICTURE TWO SEPARATE STORM SYSTEMS TOWARDS THE 
WEST. AGAIN IT APPEARS THINGS WILL GET MORE ACTIVE POSSIBLY BY NEXT 
MONDAY BUT WITH SUCH A SPREAD I HAVE CONTINUED WITH THE IDEA OF 
GHOST POPS AND INCREASED CLOUDS. AS FOR TEMPS I FLAT-LINED VALUES 
BASICALLY IN THAT ANY RISE OR DROP WILL DEPEND ON WHEN A STORM MOVES 
IN AND HEIGHTS RISE OR FALL WHICH IS HARD TO TELL WITH THE SPREAD IN 
THE SOLUTIONS PRESENTLY OUT THERE. 
&&

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

$$

JENSEN/SALMEN/STACHELSKI

HTTP://WEATHER.GOV/LASVEGAS