Area Forecast Discussion
Issued by NWS Phoenix, AZ

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085
FXUS65 KPSR 132213
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
313 PM MST SAT FEB 13 2016

.UPDATE...
UPDATED AVIATION SECTION.

&&

.SYNOPSIS...
STRONG HIGH PRESSURE AND UNSEASONABLY WARM TEMPERATURES WILL REMAIN
DOMINANT OVER THE SOUTHWESTERN UNITED STATES INTO THE MIDDLE OF NEXT
WEEK. CLEAR SKIES...DRY CONDITIONS AND RELATIVELY LIGHT WINDS WILL
CONTINUE THROUGH THE PERIOD. SOME MINOR RELIEF FROM THE UNUSUALLY
WARM CONDITIONS WILL ARRIVE BY THE END OF NEXT WEEK...BUT
TEMPERATURES WILL STILL REMAIN ABOVE SEASONAL NORMALS AND LIKELY
STILL ABOVE 80 DEGREES ACROSS MUCH OF THE LOWER DESERTS.

&&

.DISCUSSION...
CWA TEMPERATURES ARE JUST PEAKING INTO THE 80S...ON THEIR WAY TO LOW
TO MID 80 DEGREE READINGS FOR THIS AFTERNOON UNDER MOSTLY CLEAR SKIES.
MIDDAY SATELLITE LOOPS CONTINUE TO SHOW THE HIGH PRESSURE RIDGE
TRANSITIONING OFF TO OUR EAST WHILE LOSING SOME AMPLITUDE AS THE
PACIFIC STORM TRACK MOVES ONSHORE INTO THE WEST COAST. SEVERAL
EMBEDDED FEATURES ARE TRAVELING ALONG THE WESTERN FLANK OF THE
RIDGE...GENERATING SOME SCATTERED CLOUD COVERAGE ACROSS SE CA/S NV/W
AZ. THESE CLOUDS MAY TRANSLATE INTO AZ THIS AFTERNOON AHEAD OF AN
APPROACHING SHORTWAVE BUT SHOULD NOT BE BROAD ENOUGH IN COVERAGE TO
STALL ANY FURTHER DAYTIME HEATING.

UPSTREAM PACIFIC SHORTWAVE WILL HAVE TROUGHING HEIGHTS CUTTING FAR
SOUTH ENOUGH TO PASS THROUGH SOCAL AND AZ LATER TONIGHT AND INTO
SUNDAY...BUT WITH VERY DRY AIRMASS AND WEAK UL SUPPORT...BEST WE CAN
EXPECT WILL BE SOME PASSING HL CLOUDS AND MAYBE A DEGREE OR TWO
KNOCKED OFF OUR TEMPERATURES FOR TODAY AND SUNDAY. WHILE AIRMASS
TEMPERATURES WILL MOSTLY STAY BELOW 850MB TEMPS FROM EARLIER IN THE
WEEK WITH THE PASSING SHORTWAVE...INCREASING TROP THICKNESSES
PARTICULARLY THROUGH THE 1000-500MB LEVEL GENERALLY CORROBORATE THE
IDEA THAT THE WESTERN CWA/SOUTHEAST CA WILL SEE A FEW MORE DEGREES OF
WARMTH COMPARATIVE TO OUR AZ LOCALES SUNDAY. UPPER SHORTWAVE WILL
EXIT TO THE EAST BY LATE SUNDAY...WITH ANOTHER BUILDING PACIFIC RIDGE
INTRUDING INTO THE REGION FROM THE WEST. NIGHTTIME WINDS DRIVEN BY
SLP GRADIENTS WITH SFC HIGHS TO OUR NORTH WILL ALSO WORK TO KEEP
OVERNIGHT CONDITIONS ON THE WARMER SIDE AND MORE MIXED...LENDING THAT
MUCH MORE AIDE TO GETTING THE DAYS STARTED OFF WARMER. SEVERAL
RECORDS ARE IN DANGER FOR THE COMING WORK WEEK...PLEASE REFERENCE THE
CLIMATE SECTION BELOW FOR THE DETAILS.

LITTLE HAS CHANGED WITH THE FORECAST THINKING THROUGH THE MIDDLE OF
NEXT WEEK AS THE PACIFIC RIDGE REBUILDS AND SHIFTS EASTWARD OVER THE
WESTERN UNITED STATES FOR MONDAY THROUGH WEDNESDAY. 500MB HEIGHTS
ONLY INCREASE VERY SLIGHTLY THROUGH THE PERIOD...BUT WE GAIN A FEW
DEGREES OF WARMING WHICH WILL HELP TO MOVE OUR HIGHS INTO THE UPPER
80S TO AROUND 90 OVER THE LOWER DESERTS FOR TUESDAY AND WEDNESDAY.
PHOENIX WILL HAVE THE POTENTIAL TO HIT 90 DEGREES...MOST LIKELY ON
WEDNESDAY...AND THIS WOULD BE THE EARLIEST 90 DEGREE OCCURRENCE ON
RECORD AS THE CURRENT EARLIEST DATE IS FEBRUARY 24.

MODEL DETERMINISTIC AND ENSEMBLE GUIDANCE HAS BEEN FAIRLY CONSISTENT
WITH SHOWING A FAST MOVING SHORTWAVE TROUGH PASSING BY TO OUR NORTH
NEXT THURSDAY WHILE ALSO BRINGING A WEAK COLD FRONT THROUGH THE
DESERT SOUTHWEST. WE SHOULD ALSO SEE A MOISTURE INCREASE AND A
DECENT AMOUNT OF MID AND HIGH CLOUDS ON THURSDAY...BUT ANY RAIN
CHANCES WILL STAY ACROSS THE NORTHERN HALF OF ARIZONA. SOME
COOLING WILL TAKE PLACE...THOUGH LATEST GUIDANCE SHOWS THE COOLING
WILL BE LESS THAN WE THOUGHT A COUPLE DAYS AGO. HIGHS ARE LIKELY TO
DROP AROUND FIVE DEGREES OR SO WITH HIGHS MAINLY IN THE LOWER 80S
FOR BOTH THURSDAY AND FRIDAY.

THE GFS DETERMINISTIC/ENSEMBLE GUIDANCE AND EUROPEAN ENSEMBLE MEAN
INDICATE THE POTENTIAL FOR A SOUTHWESTERLY SUB-TROPICAL FLOW SETTING
UP NEXT FRIDAY AND SATURDAY...BUT SHOWING SOMEWHAT LIMITED MOISTURE.
MODELS OFTEN SHOW A DRY BIAS THIS FAR OUT...BUT AM NOT QUITE GOING TO
JUMP INTO PUTTING IN RAIN CHANCES...WOULD LIKE TO SEE ANOTHER SET OF
MODEL RUNS BEFORE DOING SO. THIS POTENTIAL SET UP MAY BRING A COUPLE
DAYS OF ISOLATED TO SCATTERED SHOWER/THUNDERSTORMS...BUT LIKELY
NOTHING OF ANY ORGANIZED NATURE.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...AND
WINDS AT THE SURFACE AND LOWER LEVELS WILL REMAIN LIGHT THROUGH
SUNDAY...A BIT MORE NOTICEABLE WEST WINDS SUNDAY AFTERNOON. CLEAR
SKIES EXCEPT FOR MINOR CIRRUS.

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

SURFACE WINDS WILL REMAIN LIGHT THROUGH 18Z SUNDAY. OVER SOUTHEAST
CALIFORNIA AND FAR SOUTHWEST ARIZONA NORTHERLY WINDS IN THE LOWER
LEVELS ABOVE THE SURFACE WILL STRENGTHEN TO 20-25 KTS WITHIN 2KFT AGL
AFT 09Z. LOCATIONS WITH LIGHT AND VARIABLE SURFACE WINDS MAY FLIRT
WITH LOW LEVEL WIND SHEAR CRITERIA. NORTHERLY SURFACE WINDS SUNDAY
AFTERNOON WILL STRENGTHEN WITH GUSTS OF 20-25 KTS. OTHERWISE...CLEAR
SKIES EXCEPT FOR MINOR CIRRUS.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
AN UNSEASONABLY STRONG HIGH PRESSURE RIDGE WILL REMAIN IN PLACE OVER
THE WESTERN STATES INTO EARLY NEXT WEEK. THIS WILL BRING MOSTLY SUNNY
SKIES AND A PERSISTENT PERIOD OF WELL ABOVE NORMAL HIGH
TEMPERATURES...WITH DAYTIME HIGHS AT MANY LOWER ELEVATION AND DESERT
SITES WARMING INTO THE UPPER 80S TO NEAR 90 DEGREES. MINIMUM HUMIDITY
LEVELS WILL HOVER IN THE TEENS ACROSS ALL DISTRICTS. LIGHT WINDS ARE
EXPECTED DURING THIS PERIOD...EXCEPT FOR AFTERNOON BREEZES MONDAY
THROUGH THURSDAY.

&&

.CLIMATE...

                   PHOENIX         |        YUMA
             FCST | RECORD /YEAR/  | FCST | RECORD /YEAR/
             HIGH                    HIGH

SAT FEB 13    86  |   88   /1957   |  87  |   93   /1957
SUN FEB 14    85  |   85   /2014   |  87  |   94   /1957
MON FEB 15    87  |   86   /2014   |  88  |   89   /2014
TUE FEB 16    89  |   84   /2014   |  88  |   88   /1981
WED FEB 17    90  |   88   /2014   |  88  |   88   /2014
THU FEB 18    84  |   86   /2014   |  83  |   90   /1981

&&

.SPOTTER INFORMATION STATEMENT...
SPOTTERS ARE ENCOURAGED TO REPORT BASED ON STANDARD OPERATING
PROCEDURES.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&

$$

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

DISCUSSION...NOLTE/KUHLMAN
AVIATION...AJ
FIRE WEATHER...MEYERS



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