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000
FXUS65 KPSR 210415 AAA
AFDPSR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PHOENIX AZ
915 PM MST MON MAY 20 2013

.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...
CLEAR SKIES AND DRY CONDITIONS CONTINUED FOR THE SOUTHWEST DESERTS
THIS AFTERNOON AND EVENING AS DRY NORTHWEST FLOW REMAINS OVER THE
AREA. TRAILING END OF A LARGE UPPER TROUGH AND UPPER LEVEL JET
TRAILING ACROSS NORTHEAST ARIZONA KEPT EARLIER PRESSURE GRADIENTS
TIGHTENED. WIDESPREAD BREEZY TO LOCALLY WINDY CONDITIONS WERE
OBSERVED ACROSS MUCH OF THE AREA TODAY...WITH EVEN PHOENIX SKY
HARBOR OBSERVING 31KT /NEAR 36 MPH/ GUSTS THIS AFTERNOON. WINDS HAVE
SINCE TAPERED BACK BUT MAY CONTINUE TO REMAIN MORE WESTERLY OR
VARIABLE OVERNIGHT BEFORE POTENTIALLY TAKING UP THEIR TYPICAL
DRAINAGE HEADINGS IN THE EARLY MORNING. WARM TEMPERATURES AND DRY
CONDITIONS WILL BE THE DAY-TO-DAY FORECAST FOR THE MAJORITY OF THE
WEEK. FOR TONIGHT...MADE SOME MINOR FORECAST ADJUSTMENTS TO TREND
WITH CURRENTS OBS...OTHERWISE NO MAJOR UPDATES NEEDED.

&&

.PREVIOUS DISCUSSIONS /ISSUED AT 153 PM MST/PDT/...
FORECAST FOR MUCH OF THE WEEK WILL BE QUIET. EASTERN PACIFIC RIDGE
WILL GRADUALLY SLIDE EASTWARD TOMORROW WITH THE RIDGE AXIS
POSITIONING ITSELF OVER ARIZONA LATE TOMORROW AFTERNOON. THERE WILL
BE A BIT OF A LAG IN TERMS OF WARMING...AS WE SHOULD ONLY GAIN ABOUT
1C OF BL WARMING TOMORROW BEFORE REACHING THE PEAK ON WEDNESDAY.
HIGHS ON TUESDAY MAY COME UP JUST SHORT OF THE 100 DEGREE MARK
ACROSS THE DESERTS...BUT SHOULD CERTAINLY HIT 100-103 BY MID WEEK.
INHERITED FORECAST CLOSELY MATCHED BEST PERFORMING GUIDANCE AND ONLY
VERY MINOR CHANGES WERE MADE. SIMILAR TEMPS EXPECTED ON THURSDAY AS
WELL BUT AS THE HIGH GRADUALLY RETREATS EASTWARD...TEMPS WILL FOLLOW
SUIT. HIGHS WILL EVENTUALLY DROP BACK INTO THE UPPER 90S BY THE END
OF THE WEEK.

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

WEST TO NORTHWEST WINDS WILL CONTINUE FOR THE TERMINALS THROUGH
SUNRISE BEFORE BECOMING MORE LIGHT AND VARIABLE IN THE NATURE. SKIES
WILL REMAIN CLEAR WITH MORE TYPICAL DIURNAL WINDS PATTERNS SETTING
UP FROM MIDDAY THROUGH EVENING TOMORROW WITH SPEEDS GENERALLY 15 KTS
OR LESS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
SOUTHWESTERLY FLOW ALOFT WILL BE IN PLACE THE LATTER HALF OF THE
WEEK THROUGH THE WEEKEND AS A TROUGH OF LOW PRESSURE REMAINS
CENTERED NEAR THE PACIFIC NORTHWEST. BREEZY TO WINDY CONDITIONS CAN
BE EXPECTED AT TIMES AS EMBEDDED DRY WEATHER DISTURBANCES PASS BY
WITHIN THE SOUTHWESTERLY FLOW. SINGLE DIGIT MINIMUM HUMIDITIES WILL
BE THE RULE. OVERNIGHT RECOVERY WILL BE POOR OVER SOUTH-CENTRAL
ARIZONA AND POOR TO FAIR OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA.


&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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DISCUSSION...NOLTE
PREVIOUS DISCUSSION...LEINS/KUHLMAN
AVIATION...NOLTE
FIRE WEATHER...AJ