268
FXUS65 KPSR 031934
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1234 PM MST THU SEP 3 2026
KEY MESSAGES
- A FEW SHOWERS AND STORMS ARE POSSIBLE ACROSS SOUTH-CENTRAL ARIZONA
LATE THIS AFTERNOON INTO EARLY THIS EVENING.
- SOME TROPICAL MOISTURE ARRIVING INTO THE REGION LATER TODAY THROUGH
EARLY FRIDAY WILL INCREASE RAIN CHANCES ACROSS THE FOOTHILLS
AND HIGHER TERRAIN AREAS EAST OF PHOENIX BEFORE CHANCES SHIFT
WESTWARD INTO SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA THIS
WEEKEND.
- TEMPERATURES WILL REMAIN IN A NEAR TO SLIGHTLY BELOW NORMAL
CATEGORY THROUGH THIS WEEKEND, RESULTING IN WIDESPREAD MINOR
HEAT RISK AND LOCALIZED AREAS OF MODERATE HEATRISK.
SHORT TERM /TODAY THROUGH FRIDAY/
LATEST OBJECTIVE ANALYSIS REVEALS A BROAD SUBTROPICAL RIDGE
EXTENDING FROM THE SOUTHERN PLAINS INTO THE SOUTHEASTERN U.S. WHILE
A BROAD TROUGH IS ENCOMPASSING THE PACIFIC NORTHWEST. THIS OVERALL
PATTERN CONFIGURATION IS RESULTING IN SOUTHWESTERLY FLOW ACROSS THE
REGION, ESPECIALLY IN THE MID TO UPPER-LEVELS, WHICH HAS ADVECTED
CONSIDERABLY DRIER AIR ALOFT. MEANWHILE, MOISTURE ADVECTION FROM
HURRICANE MARIE, LOCATED SOUTHWEST OF THE TIP OF THE BAJA
PENINSULA WILL RESULT IN A SURGE OF LOW-LEVEL MOISTURE HEADING
INTO THIS AFTERNOON AND TONIGHT WITH PWATS LIKELY TO EXCEED 1.5
INCHES ACROSS MUCH OF SOUTH-CENTRAL AND SOUTHEAST AZ WHILE MUCH
DRIER AIR WITH PWATS OF LESS THAN ONE INCH IS EXPECTED TO BE
CONFINED ACROSS SOUTHWEST AZ AND SOUTHEAST CA. THE LATEST HI-RES
GUIDANCE FOR LATER THIS AFTERNOON AND THIS EVENING DOES SHOW SOME
ISOLATED SHOWERS AND STORMS POPPING UP NEAR SOME OF THE TERRAIN
FEATURES SUCH AS THE TABLE TOP AND ESTRELLA MOUNTAINS IN SOUTH-
CENTRAL AZ, HOWEVER, THE VERY DRY AIR ABOVE 600 MB WILL LIKELY
LIMIT THE RESIDENCE TIME OF ANY ACTIVITY. SOME GUSTY WINDS AND
LOCALLY HEAVY RAINFALL WILL BE THE MAIN THREATS WITH ANY OF THESE
STORMS. HEADING INTO TONIGHT AND EARLY FRIDAY MORNING, GUIDANCE IS
SHOWING ANOTHER ROUND OF SHOWERS AND STORMS TO DEVELOP ACROSS
PORTIONS OF SOUTHEAST AZ AND MOVE NORTHWARD, AFFECTING THE
FOOTHILLS AND HIGHER TERRAIN AREAS EAST OF PHOENIX WHERE THE BEST
MOISTURE AXIS IS LIKELY TO SET UP. WITH THE ACTIVITY OVERNIGHT
INTO EARLY FRIDAY MORNING, SOME LOCALLY HEAVY RAINFALL THAT COULD
LEAD TO LOCALIZED FLOODING WILL BE THE MAIN THREAT. QUIETER
CONDITIONS ARE ANTICIPATED STARTING LATE FRIDAY MORNING AS DRIER
AIR FILTERING IN FROM THE WEST MOVES IN, DROPPING PWATS UNDER 1.3"
WITH LITTLE TO NO INSTABILITY AND THUS ELIMINATING ANY RAIN/STORM
CHANCES THROUGH THE REST OF THE DAY.
DUE TO THE PRESENCE OF THE TROUGHING ACROSS THE PACIFIC NORTHWEST,
AFTERNOON HIGH TEMPERATURES THIS AFTERNOON AND FRIDAY WILL BE WITHIN
A FEW DEGREES OF THE DAILY NORMALS AS READINGS TOP OUT IN THE UPPER
90S TO LOW 100S ACROSS MUCH OF THE LOWER DESERT COMMUNITIES. THE
ASSOCIATED HEIGHT FALLS FROM THE TROUGH WILL ALSO CAUSE SOME
AFTERNOON/EARLY EVENING BREEZINESS ACROSS PORTIONS OF SOUTHEAST CA
AND SOUTHWEST AZ WITH PEAK GUSTS UPWARDS OF 20-30 MPH, POTENTIALLY
UPWARDS OF 40 MPH IN THE TYPICAL WIND PRONE AREAS OF FAR SOUTHWEST
IMPERIAL COUNTY.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
GLOBAL MODELS ARE COMING INTO SOMEWHAT BETTER AGREEMENT WITH THE
PATTERN EVOLUTION THIS WEEKEND. BOTH THE ECMWF AND GFS SHOW HIGH
PRESSURE STRENGTHENING OVER THE SOUTHERN PLAINS WITH THE WESTERN
PERIPHERY OF THE RIDGE EXTENDING OVER E AZ AND NM. THIS WILL CAUSE
THE SUBTROPICAL JET TO SHIFT WWD BEGINNING SATURDAY, SETTING UP
BETTER MOISTURE ADVECTION OVER SOUTHEAST CA AND SOUTHWEST AZ. NBM
POPS ARE STILL NOT OVERLY IMPRESSIVE, MAINLY IN THE 20-30% RANGE
ON SATURDAY, HOWEVER THE GEFS/GFS INDICATES A FINAL SLUG OF
MOISTURE FROM MARIE BEING PULLED INTO SOUTHEAST CA ON SUNDAY WITH
PWATS RISING ABOVE 2.0". THEREFORE WE WILL HAVE TO MONITOR FOR
HEAVIER RAINFALL POTENTIAL IN PORTIONS OF SE CALIFORNIA INCLUDING
JOSHUA TREE NP ON SUNDAY. ELSEWHERE, ACROSS SOUTHCENTRAL AZ, RAIN
CHANCES LOOK TO BE MEAGER DUE TO MORE EXTENSIVE CLOUD COVER AND
VERY LOW INSTABILITY. THE LATEST WPC QPF FIELD SHOWS A LOCAL
MINIMUM IN RAINFALL TOTALS (<0.10") IN SOUTHCENTRAL AZ INCLUDING
THE PHOENIX METRO THROUGH THIS WEEKEND. BY EARLY NEXT WEEK, THERE
ARE LARGE DISCREPANCIES IN THE RIDGE/TROUGH POSITIONING WHICH WILL
COMPLICATE THE PRECIPITATION FORECAST, BUT THERE WILL STILL BE
ADEQUATE MOISTURE ACROSS OUR REGION WHICH WILL KEEP LOW END POPS
IN PLACE ACROSS EASTERN AND SOUTHEASTERN AZ MONDAY AND TUESDAY
WITH POTENTIALLY BETTER PRECIPITATION CHANCES ARRIVING WEDNESDAY.
THE TEMPERATURE FORECAST THIS WEEKEND INTO EARLY NEXT WEEK
REMAINS LARGELY UNCHANGED, ALTHOUGH THERE WILL LIKELY BE A GRADUAL
INCREASE FROM NEAR NORMAL TEMPERATURES ON SATURDAY TO SLIGHTLY
ABOVE NORMAL TEMPERATURES SUNDAY INTO EARLY NEXT WEEK AS RIDGING
STRENGTHENS OVER THE REGION. DEPENDING ON HOW STRONG THE RIDGE
GETS, NBM TEMPS COULD CLIMB A FEW MORE DEGREES IN SUBSEQUENT RUNS
AND IT IS NOT OUT OF THE QUESTION THAT WE COULD SEE LOWER DESERT
HIGHS APPROACHING 110 DEGREES AS INDICATED BY THE NBM 75TH
PERCENTILE ON MONDAY AND TUESDAY.
AVIATION
UPDATED AT 1816Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE MAIN AVIATION WEATHER IMPACT AND FORECAST UNCERTAINTY THIS TAF
PERIOD WILL BE THE POTENTIAL FOR 1-3 PERIODS OF VCTS/TSRA/VCSH
STARTING AS EARLY AS 21-22Z THIS AFTERNOON AND GOING THROUGH
13-14Z FRIDAY MORNING. PROB30 TS WAS ADDED TO KPHX FOR THIS
AFTERNOON, WITH THE POTENTIAL FOR A SHOWER OR STORM TO POP UP OVER
THE ESTRELLA MTNS. CONFIDENCE IS A LITTLE BETTER IN SHOWER AND
STORM DEVELOPMENT FRIDAY MORNING, BUT THIS ACTIVITY MAY STAY JUST
SE AND E OF TERMINALS. AN ISOLATED SHOWER OR STORM ALSO CANNOT BE
RULED OUT IN THE MIDDLE OF THE NIGHT. WINDS WILL FAVOR A S'RLY
COMPONENT FOR MUCH OF THE AFTERNOON WITH A VEERING TOWARD SW BY
22-23Z. WINDS WINDS WILL EVENTUALLY TURN BACK E'RLY TONIGHT,
LIKELY AFTER MIDNIGHT AND SPEEDS WILL INCREASE UP TO 8-13 KT BY
14-16Z. FEW TO SCT CLOUDS WILL BE COMMON WITH LOWEST DECKS AROUND
8-12 KFT THROUGH MOST OF THE TAF PERIOD.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
BREEZY CONDITIONS, ONCE AGAIN DURING THE AFTERNOON AND EVENING,
HOURS WILL BE THE MAIN AVIATION WEATHER IMPACT. WINDS AROUND 5-10
KT ARE EXPECTED THROUGH EARLY AFTERNOON BEFORE INCREASING UP TO
9-14 KT WITH GUSTS UP TO 20-25 KT LATE THIS AFTERNOON THROUGH THIS
EVENING. WIND DIRECTIONS WILL MOSTLY MAINTAIN A WESTERLY TO
SOUTHWESTERLY COMPONENT AT KIPL WHILE KBLH SWITCHES BETWEEN
SOUTHERLY AND SOUTHWESTERLY DIRECTIONS. MOSTLY CLEAR SKIES WILL
PREVAIL.
FIRE WEATHER
ISOLATED TO WIDELY SCATTERED SHOWERS AND STORMS WILL BE POSSIBLE
IN SOUTHCENTRAL AZ LATER TODAY THROUGH FRIDAY. RAIN CHANCES WILL
EXPAND WESTWARD THROUGH THIS WEEKEND, BECOMING FOCUSED OVER THE
WESTERN DISTRICTS SATURDAY AND SUNDAY. THE BEST CHANCES FOR
WETTING RAINFALL WILL BE OVER THE HIGHER TERRAIN AREAS OF EASTERN
AND SOUTHEASTERN AZ. AFTERNOON MINIMUM HUMIDITIES WILL RANGE FROM
7-15% ACROSS SOUTHEAST CA AND BETWEEN 20-35% FOR THE REMAINDER OF
THE REGION THROUGH FRIDAY AND WILL LIKELY INCREASE ABOVE 25%
AREAWIDE THIS WEEKEND. OVERNIGHT RECOVERIES WILL RANGE FROM POOR
ACROSS THE WESTERN DESERTS AND GOOD TO EXCELLENT ACROSS THE
EASTERN DISTRICTS. DAYTIME WINDS WILL REMAIN ELEVATED OUT OF THE
SOUTH TO SOUTHWEST, WITH THE STRONGEST GUSTS IN SOUTHEAST CA AND
ALONG THE LOWER COLORADO RIVER VALLEY PEAKING BETWEEN 20-30 MPH
DURING THE AFTERNOON/EARLY EVENING.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...LOJERO
LONG TERM...SALERNO
AVIATION...BENEDICT
FIRE WEATHER...WHITTOCK/SALERNO
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