000
FXUS65 KVEF 201113
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
312 AM PST THU NOV 20 2008
.SYNOPSIS....TEMPERATURES WILL TREND SLIGHTLY COOLER TODAY THROUGH
SATURDAY AS A STORM SYSTEM PASSES BY TO OUR NORTH TODAY AND ANOTHER
ON SATURDAY. A SIGNIFICANT PATTERN CHANGE IS LIKELY BY THE MIDDLE OF
NEXT WEEK...WITH TEMPERATURES FALLING CLOSER TO NORMAL AND THE
CHANCES OF RAIN AND MOUNTAIN SNOW INCREASING.
&&
.SHORT TERM...HIGH LEVEL MOISTURE IS INCREASING THIS MORNING WITH
SATELLITE SHOWING SIGNIFICANT LEESIDE ENHANCEMENT ACROSS CENTRAL
NEVADA. HIGH CLOUDS WILL BE MORE PROMINENT TODAY THEN THINKING OF
THE PAST TWO DAYS. MODEL RH PROGS SHOW MINOR BREAK IN THE HIGH
CLOUDS TONIGHT BEFORE NEXT AREA PRESENTLY ENHANCING NEAR 30N/130W
INCREASES FROM THE SOUTHWEST DURING THE DAY FRIDAY. TIGHTLY WOUND
SHORTWAVE OFF THE OREGON COAST THIS MORNING STILL PROGGED TO WEAKEN
AS IT LIFTS EAST-NORTHEAST INTO THE NORTHERN ROCKIES THIS EVENING.
ANOTHER SET OF WEAK DISTURBANCES MOVE THROUGH THE NORTHWEST STATES
SATURDAY WHILE WEAK SOUTHERN BRANCH DISTURBANCE NEAR THE SOUTHERN
CALIFORNIA COAST KEEPS SOME HIGH CLOUDS ACROSS THE MOJAVE DESERT.
THE COMBINATION OF HIGH CLOUDS AND LOWER HEIGHTS WILL LEAD TO
SLIGHTLY COOLER TEMPERATURES TODAY THROUGH SATURDAY.
.LONG TERM...SURPRISINGLY LITTLE DIFFERENCE BETWEEN THE 00Z GFS AND
ECMWF SOLUTIONS THROUGHOUT THE EXTENDED TERM. BOTH MODELS ARE
FORECASTING SIMILAR STRENGTH AND TRACK OF AN INCOMING PACIFIC STORM
FOR THE MIDDLE OF NEXT WEEK. SOME DIFFERENCE IN TIMING REMAINS WITH
THE GFS BRINGING PRECIPITATION TO THE SOUTHWESTERN CWA AS EARLY AS
TUESDAY AFTERNOON AND EVENING WHILE THE ECMWF IS ABOUT 12 HRS
SLOWER...REMAINING DRY UNTIL WEDNESDAY. OVERALL CONFIDENCE IN A
MAJOR WEATHER CHANGE FOR THE AREA NEXT WEEK IS INCREASING AS MODELS
REACH A CONSENSUS. RAMPED UP POPS BEGINNING TUESDAY NIGHT TO SLIGHT
CHANCE IN MOST AREAS INCREASING TO CHANCE ON WEDNESDAY. IF MODELS
REMAIN CONSISTENT...ADDITIONAL INCREASES WILL BE NECESSARY. THERE
COULD BE SOME DECENT QPF AMOUNTS AHEAD OF THE STORM WITH AN AREA OF
UPPER DIVERGENCE AND LOW LEVEL CONVERGENCE CENTERED OVER THE AREA.
IN ADDITION...MODEL FORECASTED PW VALUES OF ONE INCH REACH INTO THE
SOUTHERN REGIONS OF THE FORECAST AREA WHICH WOULD PROVIDE SUFFICIENT
MOISTURE. AT THIS TIME...IT IS TOO EARLY TO PREDICT AMOUNTS. WITH
THE INCREASED CLOUD COVER AND SHOWERS...TEMPERATURES WILL LIKELY BE
MUCH COOLER THAN WHAT HAS OCCURRED RECENTLY AND COULD ACTUALLY BE
BELOW NORMAL FOR THE FIRST TIME IN QUITE SOME TIME.
&&
.AVIATION...FOR MCCARRAN...LIGHT AND VARIABLE WIND CONDITIONS UNDER
6KTS EXPECTED THROUGH FRIDAY. SCT-BKN CIRRUS AOA 25K FEET EXPECTED
BY DAYBREAK THIS MORNING AND CONTINUING THROUGH THE DAY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...GENERALLY LIGHT DIURNAL WINDS LESS THAN 10KTS THROUGH
FRIDAY. SCT-BKN CIRRUS AOA 25K FEET IS EXPECTED.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&
$$
PIERCE/SALMEN
HTTP://WEATHER.GOV/LASVEGAS
