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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS65 KVEF 220420 AAA
AFDVEF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
920 PM PDT TUE MAY 21 2013

.SYNOPSIS...A LARGE AREA OF LOW PRESSURE WILL REMAIN OVER THE
PACIFIC NORTHWEST THROUGH THE COMING HOLIDAY WEEKEND WITH A DRY
SOUTHWEST FLOW OVER THE SOUTHERN GREAT BASIN AND MOJAVE DESERT. THIS
WILL LEAD TO MOSTLY CLEAR SKIES AND LOCALLY BREEZY CONDITIONS EACH
AFTERNOON WITH TEMPERATURES CLOSE TO NORMAL. WEDNESDAY WILL BE THE
WINDIEST DAY WITH GUSTS OVER 40 MPH EXPECTED OVER MUCH OF SAN
BERNARDINO AND MOHAVE COUNTIES.
&&

.UPDATE...
-- Changed Discussion --
EXTENDED PERIOD OF BREEZY TO WINDY SOUTH TO SOUTHWEST
WINDS UNDERWAY. WINDS WILL BE DRIVEN BY THE PLACEMENT OF A CLOSED
LOW OVER THE PACIFIC NORTHWEST WHICH WILL REMAIN NEARLY STATIONARY
INTO THE HOLIDAY WEEKEND. SEVERAL WIND PRODUCTS HAVE ALREADY BEEN
ISSUED FOR WEDNESDAY. LATEST HI-RES MODEL SHOWS STRONGEST WINDS
ACROSS NORTHWEST ARIZONA AND WESTERN SAN BERNARDINO COUNTY AS WELL
AS AROUND THE SPRING MTNS. CROSS SECTION ACROSS THE SRN SIERRA
NEVADA AND SPRING MTN DOES SHOW SOME DOWNSLOPE WINDS PENETRATING
DOWN THE LEESIDE SLOPES...BUT NOT AT A MAGNITUDE THAT WOULD
NECESSITATE ANY ADDITIONAL PRODUCTS.

ALL OF THE HIGH CLOUDS HAVE SHIFTED EAST SO DID UPDATE THE SKY GRIDS
FOR THE REST OF TONIGHT.
-- End Changed Discussion --
&&

.AVIATION...
-- Changed Discussion --
FOR MCCARRAN...SOUTH/SOUTHWEST WINDS 12-16 KTS WITH
GUSTS TO 25 KTS THROUGH WEDNESDAY MORNING BEFORE GUSTS TO NEAR 30KTS
ARE SEEN BY LATE WEDNESDAY MORNING THROUGH THE AFTERNOON. MOSTLY
CLEAR SKIES THROUGH WEDNESDAY.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...GENERALLY SOUTH TO SOUTHWEST WINDS 10-20 KTS WITH GUSTS
TO BETWEEN 25-30 KTS...DECREASING SOMEWHAT OVERNIGHT THEN
INCREASING AGAIN ON WEDNESDAY WITH LOCAL GUSTS TO OVER 40 MPH
ESPECIALLY IN THE WESTERN MOJAVE DESERT AND NORTHWEST ARIZONA.
MOSTLY CLEAR THROUGH WEDNESDAY.
-- End Changed Discussion --
&&

.PREV DISCUSSION...
-- Changed Discussion --
230 PM PDT TUE MAY 21 2013

.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...A FAIRLY STRONG UPPER
LOW WILL REMAIN BASICALLY STATIONARY OVER THE PACIFIC NORTHWEST WITH
A DRY SOUTHWEST FLOW OVER THE FORECAST AREA. SOME HIGH CLOUDS WILL
BE SEEN AT TIMES BUT OVERALL LOOKING AT MOSTLY CLEAR SKIES. AS THE
TROUGH INITIALLY DEEPENS WEDNESDAY WE WILL SEE THE STRONGEST WINDS
OF THE SHORT TERM PERIOD WITH MODELS INDICATING STRONG POTENTIAL FOR
GUSTS AROUND 40 MPH IN WESTERN SAN BERNARDINO AND MUCH OF MOHAVE
COUNTIES. I DECIDED TO ISSUE A WIND ADVISORY FOR THOSE AREAS
BEGINNING AT NOON WEDNESDAY. ELSEWHERE...LOCALLY BREEZY TO WINDY
CONDITIONS CAN BE EXPECTED. WINDS LOOK TO BE A LITTLE LIGHTER
THURSDAY AND FRIDAY BUT THERE WILL STILL BE AT LEAST LOCALLY BREEZY
CONDITIONS BOTH AFTERNOONS. TEMPERATURES DURING THE SHORT TERM WILL
BE PRETTY CLOSE TO NORMAL.

.LONG TERM...SATURDAY THROUGH TUESDAY...UPPER LOW WHICH HAS BEEN
OVER THE PACIFIC NORTHWEST DURING THE WEEK IS FORECAST TO BEGIN TO
SHIFT TO THE NORTH SLIGHTLY ON SATURDAY. AT THE SAME TIME A WEAK
SHORT WAVE IMPULSE MOVING THROUGH THE OVERALL TROUGH PATTERN ACROSS
THE WESTERN STATES IS FORECAST TO MOVE ACROSS THE CWA SATURDAY
AFTERNOON. THIS OVERALL PATTERN CONTINUES INTO MONDAY...HOWEVER
THERE DOES BECOME SOME MODEL DIFFERENCES AS YOU MOVE INTO THE
SUNDAY/ MONDAY TIME FRAME WITH THE ECMWF TRENDING TOWARDS A
WEAKER/FLATTER TROUGH ACROSS THE WESTERN STATES...THAN THE GFS/GEMS.
HOWEVER BY TUESDAY THE MODELS ONCE AGAIN COME INTO PRETTY GOOD
AGREEMENT. EITHER WAY...THE PATTERN CONTINUES TO KEEP THE MAIN
ENERGY FROM ANY SHORT WAVES NORTH OF THE REGION...RESULTING IN DRY
CONDITIONS THROUGH THE PERIOD. WINDS WILL CONTINUE TO BE BREEZY TO
LOCALLY WINDY...WITH SATURDAY AFTERNOON/EVENING PROBABLY BEING THE
WINDIEST PERIOD DURING THE LONG TERM. UNDER THE GENERAL
TROUGHINESS...TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL THROUGH THE
PERIOD ALSO.
-- End Changed Discussion --
&&

.FIRE WEATHER...
-- Changed Discussion --
A DRY SOUTHWEST FLOW WILL PERSIST ACROSS THE REGION
THROUGH THE REMAINDER OF THE WEEK AND INTO THE WEEKEND. AS A LOW
PRESSURE SYSTEM INITIALLY DEEPENS OVER THE PACIFIC NORTHWEST ON
WEDNESDAY...BREEZY TO WINDY CONDITIONS WILL DEVELOP...ESPECIALLY
ACROSS WESTERN SAN BERNARDINO COUNTY AND IN MOHAVE COUNTY OUTSIDE OF
THE RIVER VALLEY. GUSTS TO 40 MPH ARE LIKELY IN THESE AREAS. THE
COMBINATION OF GUSTY WINDS AND LOW RELATIVE HUMIDITY ARE EXPECTED TO
MEET RED FLAG CRITERIA IN FIRE WEATHER ZONE 102 AND THE FIRE WEATHER
WATCH WAS UPGRADED TO A WARNING. CONDITIONS WILL BE CLOSE TO RED
FLAG CRITERIA IN SOME OTHER AREAS BUT THE EITHER THE DURATION OR
GEOGRAPHICAL EXTENT WILL NOT BE SUFFICIENT TO WARRANT A RED FLAG
WARNING...OR FUELS ARE NOT REPORTED AS CRITICAL. AFTER
WEDNESDAY...LOCALLY BREEZY CONDITIONS WILL EXIST EACH AFTERNOON BUT
OVERALL THE WINDS LOOK TO BE LIGHTER.
-- End Changed Discussion --
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...WIND ADVISORY FROM NOON TO 9 PM MST WEDNESDAY FOR AZZ001-003.
     RED FLAG WARNING FROM NOON TO 9 PM MST WEDNESDAY FOR AZZ102.
CA...WIND ADVISORY FROM NOON TO 9 PM PDT WEDNESDAY FOR CAZ523.
&&

$$

UPDATE...PIERCE
PREV DISCUSSION...HARRISON/JENSEN

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