324 
FXUS65 KVEF 181627
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
827 AM PST MON FEB 18 2013

.SYNOPSIS...DRY CONDITIONS WITH ABOVE NORMAL TEMPERATURES WILL 
CONTINUE TODAY BEFORE A STRONG PACIFIC STORM MOVES INTO THE AREA ON 
TUESDAY. THIS STORM WILL RESULT IN GUSTY WINDS ACROSS THE REGION 
ALONG WITH WIDESPREAD PRECIPITATION TUESDAY NIGHT AND WEDNESDAY. 
SNOW LEVELS WILL BE LOWERING TO NEAR THE VALLEY FLOORS BY WEDNESDAY. 
UNSETTLED WEATHER WITH BELOW NORMAL TEMPERATURES WILL THEN BE 
EXPECTED THROUGH THE REMAINDER OF THE WEEK.
&&

.UPDATE...SKIES WERE CLEAR THIS MORNING ACROSS THE FORECAST AREA 
NORTH/NORTHEAST WINDS MAINLY UNDER 10 MPH. HIGH CLOUDS AHEAD OF THE 
APPROACHING STORM WILL INCREASE A BIT DURING THE DAY...MAINLY ACROSS 
THE NORTHERN PORTION OF THE FORECAST AREA. WINDS WILL GENERALLY BE 
LIGHT INTO EARLY AFTERNOON THEN INCREASE A LITTLE OUT OF THE SOUTH 
IN RESPONSE TO THE APPROACHING AREA OF LOW PRESSURE. THE INHERITED 
FORECAST REFLECTS CURRENT TRENDS AND NO UPDATES ARE PLANNED THIS 
MORNING. -HARRISON-
&&

.PREV DISCUSSION...
320 AM PST MON FEB 18 2013

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...DRY NORTHWEST FLOW 
ALOFT WILL CONTINUE THROUGH MUCH OF THE DAY TODAY BEFORE THE FLOW 
ALOFT TURNS MORE SOUTHWESTERLY IN ADVANCE OF A DEVELOPING PACIFIC 
STORM DROPPING SOUTH ALONG THE WEST COAST. MODELS ARE IN GOOD 
AGREEMENT THAT THIS SYSTEM WILL BE JUST OFF OR OVER THE NORTHERN 
CALIFORNIA COAST BY 18Z TUESDAY WITH THE CENTER OF THE SYSTEM MOVING 
TO JUST SOUTH OF SOUTHERN NEVADA BY 12Z WEDNESDAY...BEFORE SHIFTING 
EAST OUT OF THE AREA BY 00Z THURSDAY. DRIER NORTHWEST FLOW TO THEN 
BE OVER THE CWA FOR WEDNESDAY NIGHT. AS THIS SYSTEM MOVES ACROSS THE 
REGION...THE MAIN IMPACTS WILL BE PRECIPITATION...WINDS AND MUCH 
COOLER TEMPERATURES.

AS THE SYSTEM DROPS INTO NORTHERN CALIFORNIA...INCREASING 
PRECIPITATION CHANCES WILL BE SEEN OVER THE SOUTHERN SIERRA TUESDAY 
MORNING SPREADING ACROSS THE ENTIRE CWA TUESDAY NIGHT WITH DRYING 
TAKING PLACE DURING THE DAY FROM THE WEST ON WEDNESDAY. AT THIS 
TIME...SNOW ACCUMULATIONS LOOK TO BE BELOW WARNING CRITERIA ACROSS 
THE CWA...HOWEVER ADVISORY LEVEL ACCUMULATIONS WILL LIKELY BE SEEN 
IN THE HIGHER ELEVATIONS OF THE SOUTHERN SIERRA AND THE MOUNTAINS OF 
SOUTHERN NEVADA/NORTHWEST ARIZONA. THE MAIN TIMING FOR THE POTENTIAL 
OF ACCUMULATING SNOW WILL BE BETWEEN 00Z-12Z FOR THE SOUTHERN SIERRA 
AND 06Z-18Z FOR THE SOUTHERN MOUNTAINS. SNOW LEVELS WILL BE LOWERING 
TUESDAY NIGHT INTO WEDNESDAY MORNING AND NOT OUT OF THE QUESTION 
THAT LIGHT SNOW WILL BE SEEN TO THE 2500 FOOT LEVEL. ONE AREA THAT 
WILL NEED TO BE MONITORED WILL BE THE MORONGO VALLEY AREA WHERE 
UPSLOPE CONDITIONS DUE TO THE UPPER LOW POSITION MAY BRING LOCALLY 
HIGHER AMOUNTS TO THIS AREA LATE TUESDAY NIGHT INTO EARLY WEDNESDAY.

WINDS WILL BE THE SECOND CONCERN FOR THE REGION. POSSIBLE DOWNSLOPE 
WINDS MAY FORM OVER THE SOUTHERN SIERRA LATE TUESDAY/TUESDAY EVENING 
AND THEN OVER THE SPRING MOUNTAINS OF CLARK COUNTY TUESDAY NIGHT 
INTO WEDNESDAY. IN ADDITION...WIDESPREAD SOUTHWEST WINDS WILL BE 
FORMING ACROSS THE MOHAVE DESERT REGION AND INTO NORTHWEST ARIZONA 
TUESDAY AFTERNOON INTO WEDNESDAY WITH GUSTS TO NEAR 40 MPH OR 
GREATER IN SOME AREAS. WINDS WILL TURN TO THE NORTH AS THE SYSTEM 
SHIFTS ACROSS THE REGION/BEHIND THE ASSOCIATED COLD FRONT...WITH THE 
FRONTAL PASSAGE THROUGH THE LAS VEGAS VALLEY EXPECTED AROUND 00Z 
THURSDAY.

WITH THE FRONT/STORM PASSAGE...TEMPERATURES WILL BE COOLING 
CONSIDERABLY FROM THE WELL ABOVE NORMAL TEMPERATURES THAT WERE SEEN 
ON SUNDAY. ALTHOUGH TEMPERATURES WILL REMAIN ABOVE NORMAL 
TODAY...READINGS ON WEDNESDAY ARE EXPECTED TO BE AS MUCH AS 10 
DEGREES BELOW NORMAL.   

.LONG TERM...UNSETTLED WEATHER WILL CONTINUE IN THE EXTENDED AS 
LONGWAVE TROUGHING REMAINS IN PLACE ACROSS THE WESTERN STATES AND 
SEVERAL SHORTWAVES PASS OVER THE FORECAST AREA DURING THE PERIOD. 
TWO WEAK WAVES WILL QUICKLY PASS OVER THE AREA ON THURSDAY AND 
THURSDAY NIGHT BUT HAVE MINIMAL IMPACTS...WITH ONLY A MINOR INCREASE 
IN NORTHERLY WINDS AND ENHANCED CLOUD COVER. ANY PRECIPITATION 
ASSOCIATED WITH THESE FEATURES WILL BE LIMITED WITH LITTLE MOISTURE 
TO WORK WITH...BUT OPTED TO KEEP IN SLIGHT CHANCES ACROSS NORTHERN 
ZONES AND MOHAVE COUNTY. A WEAK RIDGE WILL TRANSITION OVER THE 
REGION ON FRIDAY AND PROVIDE A QUICK BREAK WITH DECREASED WINDS AND 
A SMALL INCREASE IN TEMPERATURES...BUT THE STRONGEST WAVE WILL 
FOLLOW SHORTLY BEHIND AND BRING ANOTHER ROUND OF PRECIP AND STRONGER 
NORTH WINDS TO THE AREA. NEVADA AND ARIZONA ZONES WILL SEE THE BEST 
CHANCE FOR PRECIPITATION...BUT AMOUNTS AND COVERAGE LOOK TO BE 
LESSER THAN THE SYSTEM IMPACTING THE AREA EARLIER IN THE WEEK ON 
TUESDAY/WEDNESDAY. THE BIGGEST IMPACT WITH THE WEEKEND SYSTEM WILL 
BE INCREASED NORTHERLY WINDS FOLLOWING FRONTAL PASSAGE SATURDAY 
AFTERNOON AND OVERNIGHT...WITH GUSTS UP TO 40 MPH POSSIBLE OVER A 
LARGE PART OF THE FORECAST AREA. THESE WINDS WILL CONTINUE ON 
SUNDAY. TEMPERATURES THROUGH THE PERIOD WILL REMAIN BELOW NORMAL 
WITH THE CONTINUED TROUGHING AND COLD AIR ADVECTION FROM THE NORTH. 
&&

.AVIATION...FOR MCCARRAN...WINDS ARE EXPECTED TO DECREASE SLIGHTLY 
THIS MORNING BUT FAVOR A EAST/NORTHEAST DIRECTION THROUGH THE DAY. 
WINDS ARE EXPECTED TO REMAIN BELOW 8KTS THE MAJORITY OF TIME IN THE 
AFTERNOON. A STRONG STORM SYSTEM WILL IMPACT THE AREA TUESDAY AND 
WEDNESDAY...WITH GUSTS UP TO 30KTS BY TUESDAY AFTERNOON AND 
PRECIPITATION BY TUESDAY EVENING. THE BEST CHANCES FOR PRECIPITATION 
AND CIGS AOB 5KFT WILL BE LATE TUESDAY EVENING AND WEDNESDAY MORNING.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST 
CALIFORNIA...NO SIGNIFICANT WEATHER IS EXPECTED TODAY WITH GENERALLY 
LIGHT WINDS AND MINIMAL CLOUD COVERAGE...HOWEVER...A STRONG STORM 
SYSTEM WILL IMPACT THE AREA TUESDAY AND WEDNESDAY...WITH GUSTS 
AROUND 35KTS ON AVERAGE AND MOST LOCATIONS SEEING VALLEY RAIN / MTN 
SNOW TUESDAY AFTERNOON THROUGH WEDNESDAY. 
&&

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

$$

JENSEN/KENNEDY

HTTP://WEATHER.GOV/LASVEGAS