Area Forecast Discussion
Issued by NWS Phoenix, AZ

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000
FXUS65 KPSR 281708
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1005 AM MST MON JUL 28 2014


.SYNOPSIS...
THERE WILL BE A CONTINUED CHANCE OF AFTERNOON SHOWERS AND
THUNDERSTORMS ACROSS THE FORECAST AREA TODAY...BEFORE DRIER AIR
MOVES INTO THE REGION TUESDAY THROUGH LATE WEEK. STORM CHANCES WILL
INCREASE AGAIN FRIDAY INTO THE WEEKEND AS MOISTURE MOVES BACK INTO
THE SOUTHWEST UNITED STATES.

&&

.DISCUSSION...
VISIBLE AND WATER VAPOR SATELLITE IMAGERY CLEARLY INDICATE AN MCV
SPINNING OVER EAST CENTRAL ARIZONA AND A LARGER MORE BROAD UPPER
LEVEL CIRCULATION PROGRESSIVELY MOVING NORTHWARD ACROSS BAJA
CALIFORNIA INTO SOUTHERN CALIFORNIA. BETWEEN THE TWO...A COL REGION
APPEARS TO BE FORMING OVER THE CENTRAL ARIZONA DESERTS. 12Z KPSR
RAOB SHOWS THE LIGHTER MORE VARIABLE WINDS ASSOCIATED WITH THIS COL
IN THE 700-500MB LAYER. THERE IS STILL A DECENT AMOUNT OF MOISTURE
IN PLACE ACROSS THE REGION...AROUND 1.50 INCHES OF PRECIPITABLE
WATER NOTED IN THE KTWC/KPSR SOUNDINGS...AND WITH BOTH CIRCULATIONS
PRESENT TO HELP WITH INITIATING CONVECTION...THERE ARE STILL GROUND
TO HOLD ON TO SLIGHT CHANCES OF PRECIPITATION FOR MANY AREAS OF OUR
CWA TODAY. MADE SOME SLIGHT UPWARD ADJUSTMENTS IN THE NEAR TERM
POPS...ALBEIT REFLECTING SLIGHT CHANCES FOR THE LOWER DESERTS AND
BETTER CHANCE POPS FOR OUR HIGHER TERRAIN OF JTNP AND SOUTHERN GILA
COUNTY FOR THIS AFTERNOON. OVERALL...THE LIGHTER WIND FIELDS WILL
NOT BE FAVORABLE FOR ANY TYPE OF ORGANIZED CONVECTION...BUT ANY
STORM THAT FORMS STILL HAS THE POTENTIAL TO PUSH OUT STRONG WINDS
AND HEAVY RAINFALL. MODELS PROG THESE TWO CIRCULATIONS TO MOVE NORTH
AND EAST AS THE DAY PROGRESSES...LEAVING BEHIND SUBSIDENCE DURING
THE AFTERNOON/PEAK HEATING HOURS. WITH THIS IN MIND...NUDGED POPS
DOWNWARD FOR THIS EVENING...ESPECIALLY OUT WEST ACROSS SOUTHEAST
CALIFORNIA AS ALL MODELS AGREE THAT UPPER LEVEL WINDS WILL BECOME
WESTERLY...AND DRIER...LATER TONIGHT. TEMPERATURES TODAY SHOULD BE
SIMILAR TO THAT SUNDAY AFTERNOON...100-107 DEGREES ACROSS THE LOWER
DESERTS.

TUESDAY THROUGH SUNDAY...A DRAMATIC DECREASE THE AMOUNT OF
CONVECTION ACROSS THE AREA...WITH THE FOCUS FOR ANY PRECIPITATION IN
THE MOUNTAINS EAST OF PHOENIX THROUGH THE MIDDLE OF THE WEEK. MEAN
BL MIXING RATIOS DROP TO AROUND 6 G/KG DURING THE MIDDLE PART OF THE
WEEK AND EVEN CLIMO POPS MAY END UP BEING TOO HIGH. WITH DRIER AIR
WORKING INTO THE AREA MID WEEK...TEMPS WILL LIKELY TAKE A RUN INTO
THE 105-109 RANGE ACROSS THE DESERTS. CONSEQUENTLY...THERE SHOULD BE
A SLIGHT DROP-OFF BY THE WEEKEND AS DEEPER MOISTURE MAKES ITS WAY
BACK INTO THE AREA. STILL ABOVE 100 BUT SOMEWHAT LOWER THAN THE MID
WEEK VALUES. MADE SLIGHT REDUCTIONS TO POPS ACROSS THE BOARD FROM
TUESDAY THROUGH THURSDAY BASED ON LATEST GUIDANCE WITH THE HIGHEST
VALUES DISPLACED WELL EAST OF THE DESERTS. THE MONSOON MOISTURE
WONT BE TERRIBLY FAR AWAY...WINDS PER THE TWO-THREE MOST RECENT
RUNS OF THE EUROPEAN AND GFS BRING INCREASED MIXING RATIOS BACK INTO
THE AREA FRIDAY AND ALMOST CERTAINLY BY THE WEEKEND. PRECIP CHANCES
ONCE AGAIN LOOK FAVORABLE FOR THE LATTER PORTIONS OF THE FORECAST
PERIOD ALTHOUGH ITS STILL DIFFICULT TO HIGHLIGHT ONE DAY VS ANOTHER
UNTIL WE GET A LITTLE CLOSER.



&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...
A SMALL DISTURBANCE MOVING NORTHWARD THROUGH EAST-CENTRAL ARIZONA
EARLY THIS MORNING MAY PRODUCE SOME ISOLATED SHOWERS ROUGHLY BETWEEN
PHX AND SJN UNTIL ABOUT 16Z. CLOUDINESS...BASES AOA 15 KFT
MSL...WILL ALSO BEGIN TO THIN OUT AFT 16Z. MEANWHILE...A LARGER
DISTURBANCE CENTERED OVER NORTHERN BAJA AS OF 12Z MAY LEAD TO SOME
STORM REDEVELOPMENT BY 18Z BUT CONFIDENCE TOO LOW AT THE TAF SITES
TO INSERT TEMPO TSRA.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
A WEATHER DISTURBANCE CENTERED OVER NORTHERN BAJA MAY LEAD TO THE
DEVELOPMENT OF TSTORMS BEFORE 18Z...MOST LIKELY OVER LA PAZ AND
EASTERN RIVERSIDE COUNTIES. CONFIDENCE TOO LOW AT THE TAF SITES TO
INSERT TEMPO TSRA. HOWEVER...KBLH MORE LIKELY TO SEE TSTORMS THAN
KIPL.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
A BIT OF ADDITIONAL DRYING CAN BE EXPECTED WEDNESDAY WITH LITTLE
CHANGE THURSDAY. STORM CHANCES WILL BE SLIGHT AND WILL BE LIMITED TO
THE HIGHER TERRAIN OF SOUTH-CENTRAL ARIZONA. LATE IN THE WEEK AND
OVER THE WEEKEND...AN INCREASE IN MOISTURE AND ASSOCIATED HUMIDITIES
IS ANTICIPATED AND STORM CHANCES...THOUGH SLIGHT...EXPAND TO THE
LOWER ELEVATIONS. HIGH TEMPERATURES TREND DOWNWARD AS WELL.


&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...NONE.

CA...NONE.

&&

$$

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

DISCUSSION...MEYERS/LEINS
AVIATION...AJ
FIRE WEATHER...AJ





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