FXUS65 KVEF 262230
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
230 PM PST SAT DEC 26 2009

.SYNOPSIS...UNSETTLED WEATHER WILL BE OVER THE AREA THROUGH THE END 
OF THE WEEK AS A SERIES OF WEAK PACIFIC STORMS SHIFTS EAST.
THIS PATTERN WILL BRING CONSIDERABLE CLOUDINESS AND A SLIGHT CHANCE 
OF LIGHT SHOWERS TO MAINLY THE MOUNTAINS. TEMPERATURES WILL REMAIN 
NEAR TO SLIGHTLY BELOW NORMAL.
&&

.SHORT TERM...12Z NAM TRENDING A LITTLE SLOWER THAN THE GFS BUT 
OVERALL MODELS ARE IN FAIRLY GOOD AGREEMENT THIS RUN. RIDGE OVER THE 
CWA FLATTENING AS TROUGH COMPLEX BEGINS TO PUSH INTO CALIFORNIA. 
FIRST SHORT WAVE TO MOVE INTO THE SOUTHERN SIERRA TONIGHT WITH 
MODELS SHOWING SPLIT FLOW INTO MONDAY WITH CENTER OF THE LOW OFF THE 
OREGON COAST AND TROUGH AXIS STRETCHING SOUTH TO ABOUT 25N/120W BY 
18Z MONDAY. WITH AGREEMENT OF SPLIT FLOW EXPECT VERY LITTLE 
PRECIPITATION OVER THE CWA THROUGH THE SHORT TERM AS MAIN ENERGY 
SLIDES TO THE NORTH AND WELL SOUTH OF THE AREA. FORECAST TREND FROM 
EARLY THIS MORNING STILL LOOKS VERY GOOD WITH THIS AND HAVE ONLY 
NEEDED TO MAKE MINOR TWEAKS. THUS WILL KEEP SLIGHT CHANCE POPS OVER 
THE SOUTHERN SIERRA TONIGHT AND THEN MAINLY OVER MOHAVE COUNTY LATE 
MONDAY AND MONDAY NIGHT AS TROUGH SHIFTS OVER THE CWA WITH A 
FAIRLY BROAD TROUGH AXIS OVER NEVADA BY 12Z TUESDAY. MAIN IMPACT 
FROM THIS SYSTEM WILL BE CONSIDERABLE CLOUD COVER AS A RESULT OF THE 
SPLIT FLOW WHICH WILL KEEP TEMPERATURES NEAR OR SLIGHTLY BELOW 
NORMAL THROUGH THE PERIOD.

.LONG TERM...BROAD UPPER TROUGH FORECAST TO EXIT THE AREA TUESDAY 
FOLLOWED BY ANOTHER PIECE OF ENERGY PUSHING THROUGH THE AREA 
WEDNESDAY. MODELS ARE STILL HANGING ON TO SOME QPF ACROSS MOHAVE 
COUNTY TUESDAY AFTERNOON AND HAVE INCREASED THE POPS INTO THE SLIGHT 
CHANCE CATEGORY...MAINLY FOR THE HIGHER ELEVATIONS. THE GFS AND 
ECMWF DIFFER ON WEDNESDAY SYSTEM AS THE GFS BRINGS THE SYSTEM 
FURTHER INTO NEVADA WHILE THE ECMWF KEEPS IT WELL NORTH OF THE AREA. 
THE MOST LIKELY SCENARIO WITH THIS SYSTEM IS THAT INCREASED CLOUD 
COVER WILL BE THE MAIN IMPACT. HOWEVER...DID KEEP THE CURRENT TREND 
OF SLIGHT CHANCE POPS IN THE NORTHERN ZONES. BY THURSDAY 
AFTERNOON...THE MODELS ARE FORECASTING HIGH PRESSURE TO BUILD OVER 
THE AREA WHICH WILL LEAD TO DRY CONDITIONS AND LIGHT WINDS. CURRENT 
TRENDS SHOW NORMAL TEMPERATURES AND LIGHT WINDS FOR NEW YEARS EVE. 
TEMPERATURES FOR THE REMAINDER OF THE EXTENDED PERIOD ARE FORECAST 
TO BE SLIGHTLY BELOW NORMAL. 
&&

.AVIATION...FOR MCCARRAN...NORTHEAST WINDS OF 6-8 KNOTS WILL 
CONTINUE THROUGH 02Z BEFORE DIMINISHING AND TURNING MORE TOWARD A 
SOUTHWEST DIRECTION AT 3-6 KTS. OVC HIGH CLOUDS WILL BEGIN TO LOWER 
THIS EVENING AND OVERNIGHT TO AROUND 12K FEET. NORTHEAST WINDS WILL 
AGAIN DEVELOP AFTER 18Z SUNDAY AND GENERALLY BE AROUND 5-7 KNOTS.   

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST 
CALIFORNIA...GUSTY WINDS DOWN THE COLORADO RIVER WILL DIMINISH 
AROUND 03Z TO AROUND 8-10 KNOTS. NORTH WINDS ARE EXPECTED AGAIN 
SUNDAY...BUT WIND SPEEDS ARE EXPECTED TO REMAIN AROUND 10-15 KNOTS. 
WINDS ELSEWHERE ARE EXPECTED TO REMAIN UNDER 10 KNOTS. OVC HIGH 
CLOUDS WILL BEGIN TO LOWER THIS EVENING AND OVERNIGHT TO AROUND 12K 
FEET. SOME LOWER CLOUDS ARE EXPECTED IN THE SIERRA LATE TONIGHT WITH 
LIGHT SNOW SHOWERS EXPECTED OVER THE HIGHER ELEVATIONS. 
&&

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

$$

JENSEN/GORELOW

HTTP://WEATHER.GOV/LASVEGAS