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000
FXUS65 KVEF 041738
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
938 AM PST WED DEC 4 2013

.SYNOPSIS...A STRONG COLD FRONT WILL PUSH WELL SOUTH OF THE REGION
TODAY LEAVING SIGNIFICANTLY COLDER TEMPERATURES IN ITS WAKE.
SUBFREEZING TEMPERATURES ARE EXPECTED ACROSS MUCH OF THE REGION THE
NEXT FEW NIGHTS. ANOTHER STORM SYSTEM THIS WEEKEND MAY BRING WITH IT
A THREAT OF LOW ELEVATION SNOW TO PORTIONS OF THE MOJAVE DESERT.
&&

.UPDATE...MOST OF THE CWA WAS CLEARING THIS MORNING...INCLUDING THE
STUBBORN PATCH OF CLOUDS WHICH HAD BEEN PARKED OVER THE LAS VEGAS
VALLEY FOR SEVERAL HOURS. ONLY CHANGE AT THIS TIME WAS TO TWEAK SKY
GRIDS FOR THIS AFTERNOON.
&&

.AVIATION...FOR MCCARRAN...NORTH TO NORTHWEST WINDS WILL GRADUALLY
TURN TO NORTHEAST DURING THE DAY TODAY. WEDNESDAY AND THURSDAY WILL
BE COLD WITH NO OPERATIONALLY SIGNIFICANT CLOUDS OR WINDS
EXPECTED...THEN THERE IS A CHANCE OF LIGHT SNOW AND LOW CIGS ON
SATURDAY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...NORTHERLY WINDS 10-15 KTS WITH LOCAL GUSTS TO 30 KTS
THIS MORNING. SHOWERS AND CIGS 5-8 KFT OVER EASTERN MOHAVE COUNTY
THIS MORNING WITH CLEARING IN THE AFTERNOON. WEDNESDAY AND THURSDAY
WILL BE COLD WITH NO OPERATIONALLY SIGNIFICANT CLOUDS OR WINDS
EXPECTED...THEN THERE IS A GOOD CHANCE OF RAIN AND SNOW WITH LOW
CIGS OVER MUCH OF THE AREA SATURDAY WITH SNOW LEVELS DOWN TO MOST
VALLEY LOCATIONS.
&&

.PREV DISCUSSION...
345 AM PST WED DEC 4 2013

.SHORT TERM...TODAY AND TONIGHT...ACTIVE PERIOD OF WEATHER OVER THE
LAST 24 HOURS. A STRONG COLD FRONT CONTINUES TO TRUCK SOUTHEAST
THROUGH SOUTHERN SAN BERNARDINO AND MOHAVE COUNTIES AS OF 1130Z WITH
GUSTY WINDS NEAR THE FRONT. A WIDESPREAD AREA OF SHOWERS WAS
WEAKENING BUT WAS STILL PRODUCING SOME MIXED PRECIPITATION OVER THE
LAS VEGAS VALLEY AND ELSEWHERE BEHIND THE FRONT. THIS AREA OF PRECIP
SHOULD TAPER OFF RAPIDLY OVER THE NEXT COUPLE HOURS AS HIGH PRESSURE
BUILDS IN AND SKIES CLEAR. LITTLE ACCUMULATION IS EXPECTED IN MOST
LOCATIONS. BRISK NORTH WINDS ARE EXPECTED IN MOST AREAS AREAS
TODAY...BUT WILL BE MUCH CALMER THAN YESTERDAY AND OVERNIGHT. THE
STRONGEST WINDS ARE EXPECTED ALONG THE COLORADO RIVER VALLEY...WITH
GUSTS TO 25-35 MPH POSSIBLE THROUGH THE DAY.

FOR TONIGHT...THE FIRST FREEZE OF THE SEASON IS EXPECTED ACROSS MUCH
OF THE MOHAVE DESERT REGION. THE HARD FREEZE WATCH WAS UPGRADED TO A
WARNING...BUT WAS LIMITED TO WEDNESDAY AND THURSDAY NIGHTS AS
CONFIDENCE IN HARD FREEZE TEMPERATURES WAS MUCH LOWER BY FRIDAY
NIGHT. IT SHOULD BE NOTED THAT WHILE AREAS IN THE HARD FREEZE
WARNING SHOULD DROP TO OR BELOW 32 DEGREES...NOT ALL AREAS WILL SEE
HARD FREEZE TEMPERATURES /GENERALLY BELOW 28 DEGREES/. I ELECTED TO
COMBINE FREEZE WARNING AND HARD FREEZE WARNING AREAS INTO THE SAME
HARD FREEZE WARNING IN ORDER AVOID CONFUSION.

.LONG TERM...THURSDAY THROUGH TUESDAY...MODELS ARE IN PRETTY GOOD
AGREEMENT WITH THE OVERALL PATTERN LEADING TO FAIRLY HIGH CONFIDENCE
IN THE FORECAST. A DRY NORTHWEST FLOW WILL BE OVER THE AREA THURSDAY
WITH TEMPERATURES 15 TO 20 DEGREES BELOW NORMAL. LOW TEMPERATURES
THURSDAY NIGHT STILL LOOK TO BE BELOW FREEZING ACROSS MUCH OF THE
MOJAVE DESERT. ANOTHER TROUGH WILL BE DROPPING SOUTH INTO THE
PACIFIC NORTHWEST FRIDAY WITH THE FLOW ALOFT BECOMING WESTERLY. SOME
WARMING WILL OCCUR BUT TEMPERATURES WILL REMAIN WELL BELOW NORMAL.
THE TROUGH WILL CONTINUE TO MOVE SOUTH INTO NEVADA FRIDAY NIGHT AND
SATURDAY WITH PRECIPITATION CHANCES SPREADING ACROSS THE ENTIRE
FORECAST AREA BY SATURDAY. THIS SYSTEM WILL REINFORCE THE COLD AIR
WITH SNOW LEVELS DOWN TO NEAR 2000 FEET ABOVE SEA LEVEL...OR MANY
VALLEY LOCATIONS INCLUDING LAS VEGAS. CONFIDENCE IS FAIRLY HIGH THAT
PRECIPITATION WILL OCCUR ACROSS MOST OF THE FORECAST AREA BUT
CONFIDENCE IS NOT VERY HIGH REGARDING PRECIPITATION AMOUNT. AT THIS
TIME THERE IS SOME AGREEMENT BETWEEN THE ECMWF AND GEM THAT MOHAVE
COUNTY WILL SEE THE MOST PRECIPITATION AND THAT WOULD BE LATE
SATURDAY MORNING AND SATURDAY AFTERNOON. PRECIPITATION WILL BE
ENDING FROM WEST TO EAST SATURDAY NIGHT AND A DRY NORTHWEST FLOW
WILL THEN SET UP FOR SUNDAY THROUGH TUESDAY. TEMPERATURES WILL
REMAIN WELL BELOW NORMAL.

.AVIATION...FOR MCCARRAN...GUSTY NORTHEAST WINDS EARLY WILL DECREASE
TO UNDER 10 KTS BY LATE THIS MORNING. A CHANCE FOR A FEW SHOWERS
WITH CIGS NEAR 5 KFT EARLY THIS MORNING BUT CLEARING IS EXPECTED
AFTER 13Z. MORNING BEHIND THE FRONT. WEDNESDAY AND THURSDAY WILL BE
COLD WITH NO OPERATIONALLY SIGNIFICANT CLOUDS OR WINDS
EXPECTED...THEN THERE IS A CHANCE OF LIGHT SNOW AND LOW CIGS ON
SATURDAY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...NORTHERLY WINDS 10-15 KTS BEHIND A COLD FRONT TODAY.
LOCAL GUSTS TO 30 MPH THIS MORNING. SHOWERS AND CIGS 25-35 KFT OVER
MOHAVE AND EASTERN PORTIONS OF CLARK AND SAN BERNARDINO COUNTY EARLY
THIS MORNING WITH CLEARING BY MID MORNING. WEDNESDAY AND THURSDAY
WILL BE COLD WITH NO OPERATIONALLY SIGNIFICANT CLOUDS OR WINDS
EXPECTED...THEN THERE IS A GOOD CHANCE OF RAIN AND SNOW WITH LOW
CIGS OVER MUCH OF THE AREA SATURDAY WITH SNOW LEVELS DOWN TO MOST
VALLEY LOCATIONS.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...HARD FREEZE WARNING FROM 9 PM THIS EVENING TO 9 AM PST FRIDAY
     FOR NVZ016-017-020>022.
AZ...HARD FREEZE WARNING FROM 10 PM THIS EVENING TO 10 AM MST FRIDAY
     FOR AZZ003-036.
CA...HARD FREEZE WARNING FROM 9 PM THIS EVENING TO 9 AM PST FRIDAY
     FOR CAZ522>526.
&&

$$

UPDATE...............MORGAN
SHORT TERM...........WOLCOTT
LONG TERM/AVIATION...HARRISON

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