Area Forecast Discussion
Issued by NWS Phoenix, AZ

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000
FXUS65 KPSR 301226
AFDPSR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
525 AM MST SAT MAY 30 2015

.UPDATE...TO AVIATION AND FIRE WEATHER DISCUSSIONS...

&&

.SYNOPSIS...
HOT AND DRY WEATHER WILL PERSIST OVER SOUTHEAST CALIFORNIA AND
SOUTHERN ARIZONA THIS WEEKEND WITH AFTERNOON HIGHS RANGING FROM
AROUND 102 TO 108 DEGREES FOR LOWER ELEVATION POPULATION CENTERS.
TEMPERATURES WILL COOL SOMEWHAT HEADING INTO THE MIDDLE OF NEXT
WEEK...COMING CLOSER TO THE SEASONAL NORMALS.

&&

.DISCUSSION...
EARLY MORNING WATER VAPOR IMAGERY REVEALS A STRENGTHENING RIDGE OFF
THE BAJA COAST...WITH AN IMPRESSIVE ATMOSPHERIC RIVER OF MOISTURE
MOVING TOWARD THE PAC NW. CLOSER TO ARIZONA AND SOUTHEAST
CALIFORNIA...ONLY A FEW HIGH CLOUDS ARE MOVING THROUGH THE AREA AS OF
08Z. THESE CLOUDS HAVE HAD A NEGLIGIBLE IMPACT ON TEMPERATURES THUS
FAR WITH MOST LOWER DESERT LOCALES RIGHT ON TARGET IN THE MID
70S/LOWER 80S.

THE BIG STORY THROUGH EARLY NEXT WEEK WILL BE THE ONGOING STRETCH OF
TRIPLE DIGIT TEMPERATURES ACROSS THE LOWER DESERTS. MANY LOCATIONS IN
THE PHOENIX AREA OVERACHIEVED BY A DEGREE OR TWO ON FRIDAY AND NOT
SURPRISINGLY...TODAY`S 00Z DETERMINISTIC AND BLENDED BIAS CORRECTED
GUIDANCE ARE ADVERTISING SLIGHTLY WARMER TEMPERATURES FOR THE NEXT
FEW DAYS. WHILE THE INHERITED FORECAST HIGHS FOR SATURDAY THROUGH
MONDAY WERE ALREADY IN THE BALLPARK...I MADE MINOR UPWARD ADJUSTMENTS
IN MOST LOCATIONS. GENERALLY SPEAKING...HIGHS SHOULD RANGE FROM
102-108 ACROSS THE LOWER DESERTS EACH DAY THROUGH EARLY NEXT WEEK.

ALSO WORTH MENTIONING...THERE WILL BE A BRIEF PERIOD ON SUNDAY WHERE
A FAIR AMOUNT OF BL MOISTURE /6-7 G/KG BL MIXING RATIOS/ IS ADVECTED
NORTHWARD ALONG THE AZ/NM BORDER /COURTESY OF A TRANSIENT MID LEVEL
WIND SHIFT OUT OF THE SOUTHEAST/. THIS HAS BEEN ADVERTISED BY MOST
OF THE DETERMINISTIC MODELS FOR THE PAST FEW DAYS...NOW SOME OF THE
HI-RES GUIDANCE IS STARTING TO PICK UP ON THIS MOISTURE AS WELL AS
THE POTENTIAL FOR A FEW ISOLATED SHOWERS IN THE MOUNTAINS EAST OF
PHOENIX. THE BEST CHANCES OF STORMS STILL APPEAR TO BE WELL EAST OF
OUR FORECAST AREA WHERE MOISTURE WILL BE HIGHER. NOT SEEING ANY
OBVIOUS TRIGGERS TO FIRE OFF CONVECTION OUTSIDE OF NORMAL
DIFFERENTIAL HEATING/TERRAIN CIRCULATIONS...THUS I WOULDN`T EXPECT
AREAL COVERAGE TO BE MUCH MORE THAN 10-20 PERCENT. POPS ADJUSTED
SLIGHTLY IN THE UPWARD DIRECTION.

BY EARLY NEXT WEEK AN UPPER LOW WILL MOVE THROUGH THE PAC NW WHICH
WILL SERVE TO LOWER HEIGHTS AND TEMPERATURES ACROSS MUCH OF THE
WESTERN CONUS. DIRECT IMPACTS FROM THIS LOW WILL BE NEGLIGIBLE EARLY
IN THE WEEK OUTSIDE OF A SMALL DROP IN TEMPERATURES. THE FORECAST
BECOMES A BIT MORE UNCLEAR FROM WEDNESDAY/THURSDAY ONWARD AS A
SECONDARY TROUGH/LOW MOVES THROUGH THE GREAT BASIN. EXACT TRACK OF
THE LOW IS STILL UP FOR DEBATE AMONG TODAY`S 00Z GFS/ECMWF/GEM
HOWEVER ENSEMBLE BASED GUIDANCE SUGGESTS DRY WEATHER ACROSS THE
DESERTS AND A SMALL CHANCE OF MOUNTAIN SHOWERS/TSTORMS. SEEMS MORE
THAN REASONABLE BASED ON THE MODEST INCREASE IN BL MOISTURE AHEAD OF
THIS TROUGH. THIS SECONDARY TROUGH SHOULD ALSO KNOCK TEMPERATURES
BACK A FEW MORE DEGREES...AT LEAST INTO THE MID/UPPER 90S BY LATE
NEXT WEEK.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...AND KSDL...AND
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND
KBLH...

VERY SIMILAR CONDITIONS TODAY ANTICIPATED FOR THE TERMINALS AS HIGH
PRESSURE REMAINS OVER THE REGION. PASSING CIRRUS AND AFTERNOON HIGH
TERRAIN BASED CU OVER THE MOUNTAINS OF NORTHERN AND EASTERN ARIZONA
WILL BE EXPERIENCED. WINDS WILL FOLLOW TYPICAL DIURNAL HEADINGS
EARLY...WITH THE AFTN/EVENING SHIFTS OFFSET LATER AND MOSTLY LIGHT
SPEEDS.


AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
LONGWAVE TROUGHING WILL DEVELOP BACK ACROSS THE WESTERN STATES
DURING THE WEEK WHICH WILL HELP REIGN IN SOME OF THE WARMER
TEMPERATURES AND SUPPORTING PERIODS OF ELEVATED BREEZINESS...
GENERALLY FAVORING SOUTHWEST HEADINGS. MINIMUM HUMIDITIES
WILL GENERALLY REMAIN BELOW 10 PERCENT ON THE LOWER ELEVATIONS AND
BELOW 20 PERCENT ON THE HIGHER TERRAIN. OVERNIGHT RECOVERY WILL BE
MOSTLY FAIR.

&&

.CLIMATE...
HIGH TEMPERATURE FORECAST...RECORDS...AND NORMALS FOR PHOENIX AND
YUMA THROUGH THE WEEKEND...

PHOENIX    FORECAST  RECORD        NORMAL
-------    --------  ------        ------
SAT          106     114 (1910)      99
SUN          107     109 (2012)     100
MON          106     111 (2012)     100

YUMA      FORECAST   RECORD        NORMAL
----      --------   ------        ------
SAT         103      120 (1910)     100
SUN         104      113 (2012)     100
MON         105      114 (2012)     100

&&

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

&&

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

$$

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

DISCUSSION...LEINS
AVIATION...NOLTE
FIRE WEATHER...NOLTE/AJ
CLIMATE...LEINS/MO



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