000
FXUS65 KPSR 201205
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
510 AM MST MON MAY 20 2013

.UPDATE...AVIATION AND FIRE WEATHER DISCUSSIONS.

&&

.SYNOPSIS...
STRONGER HIGH PRESSURE WILL SETTLE INTO THE REGION OVER THE NEXT
COUPLE DAYS WITH CONTINUED DRY WEATHER AND ABOVE NORMAL TEMPERATURES
THROUGH MID WEEK. CLEAR SKIES AND SOMEWHAT BREEZY AFTERNOONS ARE
EXPECTED NEARLY EVERY DAY. A DEEP LOW PRESSURE SYSTEM WILL MOVE
SOUTHEAST INTO THE GREAT BASIN BY LATE WEEK ALLOWING A SLIGHT
COOLING TREND. THE DRY CONDITIONS WILL CONTINUE THROUGH THE COMING
WEEKEND WHILE TEMPERATURES FALL BACK TO AROUND SEASONAL NORMALS
STARTING LATE THIS WEEK.

&&

.DISCUSSION...
THE LARGE TROUGH STRETCHING FROM THE CENTRAL ROCKIES INTO THE
WESTERN GREAT LAKES WILL FINALLY SEE THE WESTERN PERIPHERY ERODE AS
THE EASTERN PACIFIC RIDGE NUDGES ITS WAY EASTWARD INTO THE GREAT
BASIN BY TONIGHT. SURFACE HIGH PRESSURE CURRENTLY STRETCHING FROM
THE PACIFIC NORTHWEST INTO THE GREAT BASIN WILL QUICKLY SLIDE
SOUTHWARD TODAY BRINGING A FRONTAL BOUNDARY THROUGH THE OUR AREA.
THE FRONT WILL COME DOWN THE LOWER COLORADO RIVER VALLEY BY LATE
MORNING WITH INCREASING NORTHERLY WINDS AND DRIER AIR BEHIND THE
FRONT. BREEZY TO WINDY CONDITIONS WITH GUSTS TO AROUND 30 MPH ARE
EXPECTED STARTING LATE THIS MORNING DOWN THE LOWER COLORADO RIVER
VALLEY AND EXPANDING EASTWARD THROUGH SOUTH-CENTRAL ARIZONA LATE
THIS AFTERNOON.

AS THE UPPER RIDGE BUILDS IN THROUGH TUESDAY...WILL SEE AN INCREASE
IN TEMPERATURES WITH LOWER DESERT READINGS AROUND 100F BOTH TUESDAY
AND WEDNESDAY. THE RIDGE AXIS WILL PASS THROUGH TUESDAY NIGHT WITH A
RETURN TO SOUTHWESTERLY UPPER FLOW THEREAFTER. MODELS CONTINUE TO
ADVERTISE A DEEP CLOSED LOW MOVING INTO THE PACIFIC NORTHWEST ON
WEDNESDAY AND THEN DRIFTING SOUTHEASTWARD INTO THE GREAT BASIN FOR
LATE THIS WEEK. MODEL CONSENSUS IS FAIRLY HIGH NOW THAT THE
EXPANSIVENESS OF THE UPPER LOW WILL AFFECT THE DESERT SOUTHWEST AT
LEAST PARTIALLY...RESULTING IN SLIGHTLY COOLER CONDITIONS. HAVE
LOWERED TEMPERATURES SEVERAL DEGREES STARTING THURSDAY AND THROUGH
THE WEEKEND WITH THE COOLEST TEMPERATURES ACROSS WESTERN PORTIONS OF
THE CWA. THERE IS STILL SOME QUESTION ON HOW FAR SOUTH THIS CLOSED
UPPER LOW WILL GET...WITH A MORE SOUTHERN SOLUTION RESULTING IN
COOLER TEMPERATURES AND A NORTHERN SOLUTION IN WARMER TEMPERATURES.
EITHER WAY THE REGION WILL REMAIN UNDER A DRY WESTERLY FLOW WITH
LITTLE IN THE WAY OF ANY CLOUDINESS. MOST DAYS WILL ALSO SEE FAIRLY
BREEZY AFTERNOON CONDITIONS...BUT GUSTS SHOULD GENERALLY REMAIN
UNDER 30 MPH. THE LARGE SCALE PATTERN BEYOND THIS COMING WEEKEND
SUGGESTS A TROUGH/RIDGE/TROUGH PATTERN ACROSS THE CONUS WHICH WILL
LIKELY KEEP OUR TEMPERATURES AT OR SLIGHTLY BELOW NORMAL ACROSS THE
DESERT SOUTHWEST INTO EARLY NEXT WEEK.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA...KSDL...
THROUGH 03Z TUE...CLEAR SKIES. INCREASING WEST WIND 15 TO 25 KNOTS
BTWN 19Z MON AND 03Z TUE. FROM 03Z TUE TO 12Z TUE...CLEAR SKIES.
WEST WIND 5 TO 10 KNOTS.

SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA...INCLUDING KIPL AND
KBLH...
THROUGH 03Z TUE...CLEAR SKIES. INCREASING NORTH WIND 17 TO 27 KNOTS
FROM 19Z MON TO 03Z TUE. FROM 03Z TUE TO 12Z TUE...CLEAR SKIES.
NORTH WIND 5 TO 10 KNOTS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
A LARGE AND STRONG PACIFIC LOW PRESSURE SYSTEM WILL DEVELOP OVER THE
WESTERN STATES NORTH OF AZ. HOWEVER...GUSTY WEST WINDS WITH LOW
HUMIDITY WILL DEVELOP EVERY AFTERNOON. OVERNIGHT RECOVERY WILL
BECOME GOOD OVER PORTIONS OF SOUTHEAST CALIFORNIA AND FAR SOUTHWEST
ARIZONA...BUT REMAIN POOR ELSEWHERE. AT THIS TIME...CONDITIONS ARE
EXPECTED TO REMAIN BELOW CRITICAL THRESHOLDS.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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DISCUSSION...KUHLMAN
AVIATION...VASQUEZ
FIRE WEATHER...VASQUEZ/AJ