Weather Service Report


033 
FXUS65 KPSR 231203 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
500 AM MST SUN NOV 23 2014

.UPDATE...
UPDATED AVIATION AND FIRE WEATHER SECTIONS.

&&

.SYNOPSIS...
DRY NORTHWEST FLOW ALOFT WILL BE THE RULE THIS WEEKEND AND INTO
EARLY NEXT WEEK FOR MOSTLY SUNNY DAYS...CLEAR NIGHTS...AND NEAR
SEASONAL NORMAL HIGH TEMPERATURES. HIGH PRESSURE WILL REBUILD OVER 
THE REGION BY THE MIDDLE OF NEXT WEEK...PROVIDING CLEAR SKIES AND 
WELL ABOVE NORMAL AFTERNOON TEMPERATURES. NO PRECIPITATION IS 
EXPECTED FOR AT LEAST THE NEXT SEVEN DAYS.

&&
   
.DISCUSSION... 
DRY NORTHWEST FLOW ALOFT IS IN PLACE ACROSS ARIZONA EARLY THIS 
MORNING...AS SEEN IN THE PLOT AND SOUNDING DATA. IR IMAGERY AT 1 AM 
SHOWED MOSTLY CLEAR SKIES ACROSS SERN CA AND ARIZONA...WITH JUST A 
BIT OF MOSTLY THIN HIGH CLOUD SPREADING IN FROM THE NORTHWEST. AS 
THE UPPER RIDGE AMPLIFIES JUST OFF THE WEST COAST TODAY...A 
SHORTWAVE WILL DIVE SOUTHEAST DOWN THE FRONT SIDE OF THE RIDGE AND 
PASS THRU THE FOUR CORNERS AREA...AND IN RESPONSE LOW/MID LEVEL 
GRADIENTS WILL TIGHTEN. THIS WILL LEAD TO BREEZY/WINDY CONDITIONS 
OVER THE WESTERN DESERTS...ESPECIALLY DOWN THE LOWER COLORADO RIVER 
VALLEY WHERE NORTH WINDS WILL DEVELOP TODAY AND EXCEED 30 MPH AT 
TIMES DURING THE MIDDLE OF THE DAY. FOR THE MOST PART WINDS WILL 
REMAIN A BIT BELOW WIND ADVISORY CRITERIA BUT THERE MAY BE ISOLATED 
INSTANCES OF WINDS PEAKING BETWEEN 35-40 MPH. OTHERWISE...HIGH TEMPS 
TODAY WILL HOVER NEAR SEASONAL NORMALS...BUT WILL FALL OF ACROSS 
SOUTH CENTRAL AZ MONDAY AS COOLER AIR FILTERS ACROSS THE DESERTS 
BEHIND THE PASSING SHORTWAVE. EXPECT HIGHS FALLING INTO THE 60S 
MONDAY OVER THE CENTRAL DESERTS...WITH A HIGH OF 67 FORECAST FOR 
PHOENIX UNDER SUNNY SKIES.

FOR MONDAY INTO THE MIDDLE OF THE WEEK...DRY NORTHWEST FLOW ALOFT 
WILL PERSIST EACH DAY AS THE RIDGE TO OUR WEST CONTINUES TO AMPLIFY 
AND SHIFT EASTWARD. BY WEDNESDAY AFTERNOON THE RIDGE IS FORECAST TO 
MOVE INLAND OVER THE DESERT SOUTHWEST...WITH H5 HEIGHTS CLIMBING TO 
AROUND 585DM OVER THE WESTERN DESERTS. AS SUCH...EXPECT A WARMING 
TREND THRU MIDWEEK WITH HIGHS RISING MAINLY INTO THE MID 70S OVER 
THE LOWER DESERTS WEDNESDAY. DESPITE THE RIDGE BEGINNING TO FLATTEN 
A BIT THURSDAY...WARM AIR ALOFT WILL CONTINUE TO MIX TO THE SURFACE 
AND BEST PERFORMING GRIDDED GUIDANCE CALLS FOR HIGHS TO RISE SEVERAL 
MORE DEGREES...AND INTO THE LOWER 80S. THE HIGH AT PHOENIX WILL 
CLIMB TO 81...MORE THAN 10 DEGREES ABOVE THE NORMAL VALUE OF 70 
DEGREES. THERE WILL BE OCCASIONAL HIGH CLOUDS MOVING THRU THE FLOW 
EACH DAY BUT OVERALL EXPECT SUNNY OR MOSTLY SUNNY DAYS AND GENERALLY 
CLEAR NIGHTS.

TOWARD THE END OF THE WEEK...GUIDANCE CALLS FOR THE RIDGE TO 
CONTINUE TO FLATTEN AS THE FLOW PATTERN BECOMES MORE ZONAL AND 
PROGRESSIVE. DESPITE ENSEMBLE MEMBERS BECOMING VERY MESSY WITH 
TIME...OPERATIONAL GFS AND ECMWF RUNS AGREE THAT FAR SERN AZ AND SRN 
AZ WILL STAY UNDER A RATHER DRY WESTERLY FLOW ALOFT THRU SATURDAY 
WITH OCCASIONAL HIGH CLOUDS MOVING THRU THE FLOW. HIGH TEMPS WILL 
START TO FALL OFF BUT SHOULD REMAIN WELL ABOVE SEASONAL NORMALS EACH 
DAY.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
WESTERLY FLOW ABOVE THE SURFACE WILL TURN NORTHERLY THIS MORNING AS 
A DRY FRONT SAGS SOUTHWARD THROUGH ARIZONA.  AIRFIELDS WILL FAVOR A 
NORTHERLY COMPONENT BY MIDDAY. SUSTAINED SURFACE WINDS ARE EXPECTED 
TO REMAIN AT OR BELOW 12 KNOTS. OVERNIGHT...WINDS JUST ABOVE THE 
SURFACE WILL BE NORTHEASTERLY BUT WILL BE MORE VARIABLE AT THE 
SURFACE DUE TO LOCAL TERRAIN INFLUENCES. SKIES WILL BE CLEAR EXCEPT 
FOR THIN CIRRUS.  

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA...INCLUDING KIPL AND 
KBLH...

STRONG NORTHERLY LOWER LEVEL WINDS ABOVE THE SURFACE COMBINED WITH 
LIGHT WINDS AT THE SURFACE WILL LEAD TO AREAS OF LOW LEVEL WIND 
SHEAR UNTIL ABOUT 16-17Z THIS MORNING. NORTHERLY SURFACE WINDS WILL 
DEVELOP BY MID MORNING...STRONGEST OVER AND NEAR THE LOWER COLORADO 
RIVER VALLEY WITH GUSTS OF 25-30 KTS AND ISOLATED 35 KTS...BEFORE 
SLOWLY WEAKENING BY LATE AFTERNOON. WINDS WILL NOT BE QUITE AS 
STRONG OVER THE IMPERIAL VALLEY BUT GUSTS OF 20-25 KTS WILL BE 
COMMON. SURFACE WINDS WILL BE MUCH LIGHTER OVERNIGHT THOUGH THE 
LOWER LEVELS ABOVE THE SURFACE WILL BE STRONGER...NOT ENOUGH TO 
WARRANT MENTION OF LLWS AT THIS TIME. SKIES WILL BE CLEAR EXCEPT FOR 
THIN CIRRUS. 

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
STRONG SURFACE HIGH PRESSURE CENTERED OVER COLORADO WILL LEAD TO 
LOCALIZED NORTH AND NORTHEAST BREEZINESS TUESDAY. LIGHT WINDS CAN 
THEN BE EXPECTED ACROSS THE FORECAST AREA WEDNESDAY THROUGH 
SATURDAY. TEMPERATURES WILL START OFF A BIT BELOW NORMAL TUESDAY 
FOLLOWED BY A SUBSTANTIAL WARMING TREND WEDNESDAY AND THURSDAY AS A 
RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION. AS THE RIDGE WEAKENS 
LATE IN THE WEEK...TEMPERATURES WILL NUDGE DOWNWARD. MINIMUM 
HUMIDITIES WILL REMAIN LOW...10-15 PERCENT...WITH MODEST OVERNIGHT 
RECOVERY. 

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...CB
AVIATION....AJ
FIRE WEATHER...AJ




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