FXUS65 KVEF 231707 AAA
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
900 AM PST WED DEC 23 2009

.SYNOPSIS...THE REGION WILL BE UNDER A COOL...DRY NORTH FLOW TODAY 
THROUGH CHRISTMAS DAY. THE NEXT SYSTEM TO IMPACT THE AREA WILL 
ARRIVE EARLY NEXT WEEK.
&&

.UPDATE...UPPER LOW CONTINUE TO SPIN EAST OF THE REGION WITH A COOL 
NORTHERLY FLOW LEFT OVER. CWA NEARLY CLOUD FREE THIS MORNING...BUT 
DO EXPECT A FEW CUMULUS TO DEVELOP OVER THE HIGHER TERRAIN THIS 
AFTERNOON...BUT ARE NOT EXPECTED TO AMOUNT TO ANYTHING. STILL SOME 
AREAS OF GUSTY WINDS OVER SAN BERNARDINO COUNTY...BUT GRADIENTS ARE 
STARTING TO RELAX AND WINDS WILL CONTINUE TO DIMINISH. NO UPDATES 
PLANNED.  -GORELOW-

.AVIATION...FOR MCCARRAN...NORTHWEST WINDS WILL CONTINUE TODAY WITH 
SUSTAINED WINDS AVERAGING CLOSE TO 15 TO 20 KTS AND GUSTS FROM 25 TO 
30KTS. WINDS WILL BEGIN TO DECREASE THIS AFTERNOON AS THE SURFACE 
PRESSURE GRADIENT CONTINUES TO RELAX...WITH THE THREAT OF GUSTS 
ABOVE 25KTS EXPECTED TO BE GONE BY ABOUT 22Z. WINDS WILL THEN 
CONTINUE TO DECREASE INTO THE EVENING. A FEW CLOUDS AOA 12K FEET 
ANTICIPATED THROUGH THE DAY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST 
CALIFORNIA...NORTHERLY WINDS EXPECTED WITH GUSTS UP TO 35KTS 
THROUGHOUT THE MAJORITY OF THE DAY...FINALLY DECREASING LATE THIS 
AFTERNOON AND INTO THE EVENING. MOSTLY CLEAR CONDITIONS WEST WITH 
SCT-BKN CLOUDS CENTRAL AND EAST. -KENNEDY-
&&   

.PREVIOUS DISCUSSION...240 AM PST WED DEC 23...SHORT TERM...STRONG 
UPPER LOW IS OVER NORTHEAST ARIZONA THIS MORNING WITH SATELLITE 
SHOWING CLOUDS WRAPPING BACK ACROSS NORTHWEST ARIZONA AND SOUTHEAST 
NEVADA. CLOUDS WILL DISSIPATE THROUGH THE  MORNING HOURS DUE TO 
UPPER LOW MOVING FURTHER EAST AND SUBSIDENCE ASSOCIATED WITH RIDGE 
MOVING TOWARD THE WEST COAST. THE GUSTY NORTH WINDS WILL ALSO 
CONTINUE THROUGH THE MORNING HOURS BEFORE GRADIENT STARTS TO RELAX 
THIS AFTERNOON. AREA WILL LIE UNDER A DRY...COOL NORTH FLOW THURSDAY 
AND CHRISTMAS DAY AS RIDGE SLOWLY SLIDES EAST OVER THE GREAT BASIN 
BY SATURDAY. A PERSISTENT NORTHERLY SURFACE PRESSURE GRADIENT WILL 
MAINTAIN SOME NORTH BREEZES DOWN THE COLORADO RIVER VALLEY THROUGH 
CHRISTMAS DAY.

.LONG TERM...MODELS ARE QUITE DIFFERENT IN THEIR SOLUTIONS FOR 
SATURDAY WITH THE ECMWF BRINGING A NEGATIVELY TILTED TROUGH INTO 
NORTHERN CALIFORNIA AND OREGON WHILE THE GFS HAS A WEAK LOW MOVING 
INTO SOUTHERN CALIFORNIA. EITHER SOLUTION PROVIDES LITTLE TO NO 
PRECIP FOR THE AREA AND BASICALLY KEEPS A LID ON TEMPERATURES. 
AGREEMENT ACTUALLY BECOMES BETTER SUNDAY AND MONDAY ALTHOUGH MODELS 
GET TO THEIR RESPECTIVE SOLUTIONS VIA DIFFERENT MEANS. YET AGAIN 
MOISTURE IS LIMITED AND THE TRACK SUGGESTS PRECIP...AT LEAST WHAT 
THERE IS...WILL BE CONFINED TO THE SOUTHERN REGIONS OF THE CWA. AND 
AGAIN...TEMPERATURES IN THIS TROFY PATTERN WILL BE ON THE COOL SIDE. 
MID TO LATE IN THE WEEK...ANOTHER STORM HEADS IN THIS DIRECTION AND 
MAY BRING A BETTER CHANCE OF MEASURABLE PRECIPITATION. OVERALL... 
CONFIDENCE IS LOW IN ANY DEFINITE STORM TRACK OR TIMING BUT HIGHER 
WITH REGARDS TO MAINTAINING COOLER CONDITIONS THROUGH THE TERM.
&&

.AVIATION...FOR MCCARRAN...NORTHWEST WINDS EXPECTED TO CONTINUE 
THROUGH MUCH OF THE DAY WITH SUSTAINED 12-18KTS AND GUSTS TO AROUND 
25KTS. SOME DECREASE IN WIND EXPECTED BY LATE IN THE AFTERNOON TO 
EARLY THIS EVENING. A FEW CLOUDS AOA 12K FEET ANTICIPATED THROUGH 
THE DAY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST 
CALIFORNIA...GENERALLY NORTHERLY WINDS EXPECTED WITH GUSTS TO AROUND 
25KTS MOST AREAS GRADUALLY DIMINISHING WEST TO EAST THROUGH THE DAY. 
MOSTLY CLEAR CONDITIONS WEST WITH SCT-BKN CLOUDS CENTRAL AND EAST. 
CIGS BETWEEN 2-5K FEET THIS MORNING ARE EXPECTED TO RAPIDLY CLEAR 
THIS AFTERNOON. 
&&   

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

$$

PIERCE/SALMEN

HTTP://WEATHER.GOV/LASVEGAS