167
FXUS65 KPSR 041826
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1126 AM MST FRI SEP 4 2026
UPDATE
UPDATED 18Z AVIATION DISCUSSION.
KEY MESSAGES
- RESIDUAL TROPICAL MOISTURE WILL CONTINUE TO STREAM INTO
SOUTHEASTERN AZ ON FRIDAY, PROMOTING SCATTERED SHOWERS AND
STORMS ACROSS THE FOOTHILLS AND HIGHER TERRAIN AREAS EAST OF
PHOENIX
- THE MOISTURE AXIS AND CORRESPONDING RAIN CHANCES WILL SHIFT
WEST INTO SE CALIFORNIA AND SW ARIZONA ON SATURDAY AND SUNDAY.
- TEMPERATURES WILL REMAIN IN A NEAR TO SLIGHTLY BELOW NORMAL
CATEGORY THROUGH THIS WEEKEND WITH HIGHS WARMING BACK ABOVE
NORMAL EARLY NEXT WEEK, RESULTING IN HEATRISK INCREASING FROM
WIDESPREAD MINOR TO MODERATE.
SHORT TERM /TODAY THROUGH SUNDAY/
LATEST WV IMAGERY AND 500 MB STREAMLINE ANALYSIS REVEALS AN
ELONGATED AREA OF HIGH PRESSURE EXTENDING FROM THE SOUTHERN PLAINS
INTO THE SOUTHEASTERN U.S. WHILE A BROAD TROUGH ENCOMPASSES THE
PACIFIC NORTHWEST AND MUCH OF THE WEST COAST. OUR FORECAST AREA
REMAINS CENTERED BETWEEN BOTH OF THESE FEATURES, RESULTING IN
CONTINUED DRY SOUTHWEST FLOW ALOFT. MEANWHILE, HURRICANE MARIE IS
CHURNING OVER THE E PACIFIC, WELL SOUTHWEST OF THE TIP OF THE BAJA
PENINSULA. A PLUME OF MOISTURE FROM THIS STORM CONTINUES TO
ADVECT THROUGH N MEXICO AND INTO SOUTHEASTERN AZ OVERNIGHT.
ISOLATED SHOWERS WITH A FEW EMBEDDED LIGHTNING STRIKES HAVE BEEN
FORMING OVER THE FOOTHILLS AND HIGH TERRAIN NE OF PHOENIX, AND
THIS WILL LIKELY CONTINUE OVERNIGHT AND INTO EARLY THIS MORNING
WHERE POPS RANGE FROM 30-50%. BY THIS AFTERNOON, A SHARP MOISTURE
GRADIENT WILL AGAIN BE PRESENT ACROSS THE LOWER DESERTS AS DRIER
AIR ASSOCIATED WITH THE PACIFIC TROUGH OVERSPREADS SE CALIFORNIA
AND SW ARIZONA. ALTHOUGH PWATS IN SOUTHCENTRAL AZ WILL REMAIN
MEAGER AROUND 1.4- 1.5", THERE WILL BE JUST ENOUGH LATE AFTERNOON
INSTABILITY (MUCAPE ~500 J/KG) FOR A FEW POP UP SHOWERS AND STORMS
IN CENTRAL MARICOPA AND N PINAL COUNTIES. ANY SHOWER ACTIVITY
WILL LIKELY BE SHORT-LIVED AND WANE QUICKLY AFTER SUNSET DUE TO
LOSS OF SFC HEATING.
HURRICANE MARIE WILL CONTINUE TO TRACK SLOWLY NORTHWESTWARD INTO
OPEN WATERS THROUGH THIS WEEKEND WHICH WILL ALLOW ADDITIONAL
MOISTURE TO BE TRANSPORTED NWD INTO SOCAL AND SOUTHERN AZ AS PWATS
RISE TO AROUND 1.6-1.8" AREAWIDE. ON SATURDAY, RIDGING ALOFT WILL
ALSO BEGIN TO STRENGTHEN OVER THE SOUTHERN PLAINS AND RETROGRADE
WWD, CAUSING THE SUBTROPICAL JET AXIS TO SHIFT OVER SE CALIFORNIA
AND WESTERN AZ. THEREFORE, WE WILL SEE AN ABRUPT SHIFT IN POPS
FROM E TO W WITH SHOWER ACTIVITY BECOMING FOCUSED OVER SE
CALIFORNIA AND SW ARIZONA BY SATURDAY AFTERNOON. DUE TO INCREASING
MOISTURE AND EXTENSIVE CLOUD COVER, INSTABILITY AND LAPSE RATES
WILL BE POOR AND THUS THE THREAT FOR ANY HEAVY RAINFALL WILL
REMAIN LOW. RAINFALL ACCUMULATIONS ACROSS THE WESTERN HALF OF THE
FORECAST AREA LOOK TO REMAIN LIGHT, AROUND 0.10" OR LESS THROUGH
SUNDAY. THE LATEST WPC QPF TOTALS STILL INDICATED VOID IN
PRECIPITATION ACROSS SOUTHCENTRAL AZ INCLUDING THE PHOENIX METRO
SATURDAY AND SUNDAY.
DUE TO THE PRESENCE OF TROUGHING TO OUR WEST HELPING TO MAINTAIN
500 MB HGHTS WITHIN A 588-590 DAM RANGE, TEMPERATURES WILL REMAIN
NEAR TO SLIGHTLY BELOW NORMAL THROUGH THIS WEEKEND. LOWER DESERT
HIGHS WILL RANGE FROM THE UPPER 90S TO LOWER 100S EACH AFTERNOON
WITH SATURDAY BEING THE "COOLEST" DAY OVERALL. MORNING LOWS WILL
ALSO REMAIN NEAR NORMAL MAINLY IN THE UPPER 70S TO MIDDLE 80S. THE
ASSOCIATED HEIGHT FALLS FROM THE WEST COAST TROUGH WILL ALSO
RESULT IN AFTERNOON/EARLY EVENING BREEZINESS ACROSS PORTIONS OF
SOUTHEAST CA AND SOUTHWEST AZ WITH PEAK GUSTS AROUND 20-30 MPH,
POTENTIALLY REACHING UP TO 40 MPH IN THE TYPICAL WIND PRONE AREAS
OF FAR SOUTHWEST IMPERIAL COUNTY.
LONG TERM /MONDAY THROUGH THURSDAY/
DETERMINISTIC AND ENSEMBLE GUIDANCE CONTINUE TO DIFFER ON THE
MAGNITUDE AND POSITIONING OF THE SUBTROPICAL RIDGE EARLY NEXT WEEK
WHICH WILL DICTATE HOW HOT TEMPERATURES GET AND HOW SOON RAIN
CHANCES WILL RETURN TO OUR AREA. BOTH THE EPS AND GEFS SHOW THE
RIDGE STRENGTHENING OVER THE SOUTHERN PLAINS THROUGH THE MIDDLE OF
THE WEEK WHICH WILL ALLOW HGHTS ALOFT TO INCREASE ACROSS MUCH OF
THE DESERT SOUTHWEST. IN TURN, TEMPERATURES WILL ALSO INCREASE
FROM NEAR NORMAL MONDAY TO SLIGHTLY ABOVE NORMAL ON TUESDAY. THE
TEMPERATURE FORECAST BECOMES MUCH MORE UNCLEAR HEADING INTO THE
MIDDLE OF NEXT WEEK WITH LARGE SPREADS IN THE NBM INTERQUARTILE
RANGE. THIS IS LIKELY DUE TO DIFFERENCES IN THE MAGNITUDE OF THE
RIDGE WITH MANY EPS MEMBERS SHOWING A STRONGER RIDGE WITH 500 MB
HGHTS APPROACHING 596-598 DAM WHILE THE GEFS SHOWS SLIGHTLY LOWER
OVERALL HGHTS. FOR NOW NBM TEMPERATURES SHOW A COOLING TREND AFTER
TUESDAY WHICH IS LIKELY DUE TO AN INCREASE IN MOISTURE AS
SOUTHEASTERLY FLOW ALOFT RETURNS TO THE LOWER DESERTS.
PWATS ARE EXPECTED TO INCREASE BACK TO AROUND 1.5-1.8" BY THE
MIDDLE OF NEXT WEEK WHICH WILL BRING RAIN CHANCES BACK INTO THE
PICTURE BY THE WEDNESDAY-THURSDAY TIMEFRAME WHEN POPS INCREASE TO
AROUND 20-40% AREAWIDE. THE GFS IS EVEN SHOWING AN EASTERLY
WAVE/INVERTED TROUGH ARRIVING INTO SOUTHERN AZ ALONG WITH
ADDITIONAL TROPICAL PACIFIC MOISTURE ON WEDNESDAY WHICH COULD
BOOST RAIN CHANCES SIGNIFICANTLY, BUT WE WILL LIKELY HAVE TO WAIT
FOR MORE RUN TO RUN CONSISTENCY AS THESE FEATURES ARE ALWAYS
DIFFICULT TO RESOLVE AT LONGER TIME SCALES. EITHER WAY, MOST OF
THE GEFS AND EPS MEMBERS ARE SHOWING MEASURABLE PRECIPITATION
ACROSS PORTIONS OF THE AREA BY THE MIDDLE OF NEXT WEEK.
AVIATION
UPDATED AT 1826Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
WINDS WILL FOLLOW A SIMILAR PATTERN TO YESTERDAY, WITH A SSE-SSW
DIRECTION FOR MOST OF THE DAY AND A VEERING TREND TO W-SW THIS
EVENING. WIND SPEEDS WILL MOSTLY BE IN THE 5-10 KT RANGE WITH
OCCASIONAL GUSTS INTO THE TEENS. SCATTERED CUMULUS, BASED AROUND
10K FT AGL, WILL DEVELOP THROUGH THIS AFTERNOON WITH A VERY LOW
CHANCE (5-10%) FOR A BRIEF ISOLATED SHOWER OR STORM LATE THIS
AFTERNOON AND EVENING. LIGHT E'RLY WINDS WILL EVENTUALLY DEVELOP
AFTER MIDNIGHT TONIGHT AND THEN A S'RLY COMPONENT WILL DEVELOP
AGAIN BY MIDDAY SATURDAY, BUT A QUICKER MORE PRONOUNCED W'RLY
SHIFT IS ANTICIPATED SATURDAY AFTERNOON. SCT HIGH CLOUDS WILL
OVERSPREAD THE AREA SATURDAY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
AFTERNOON THROUGH EARLY EVENING GUSTY WINDS WILL BE THE MAIN
WEATHER IMPACT THROUGH THE TAF PERIOD. GUSTS 20-25KT WILL BE
COMMON AT BOTH TERMINALS, FROM THE S-SW AT KBLH THIS AFTERNOON AND
FROM THE W-SW AT KIPL THIS EVENING. SPEEDS WILL RELAX OVERNIGHT
AND EARLY MORNING WHERE BRIEF PERIODS OF NEARLY CALM CONDITIONS
WILL EXIST. MOSTLY CLEAR SKIES WILL PREVAIL THOUGH THIS EVENING
BEFORE MID AND HIGH CLOUDS OVERSPREAD THE AREA HEADING INTO
SATURDAY.
FIRE WEATHER
ISOLATED SHOWERS AND STORMS WILL BE POSSIBLE IN SOUTHCENTRAL AZ
THIS MORNING AND AGAIN LATE THIS AFTERNOON. RAIN CHANCES WILL
EXPAND WESTWARD THROUGH THIS WEEKEND, BECOMING FOCUSED OVER THE
WESTERN DISTRICTS SATURDAY AND SUNDAY. THE BEST CHANCE FOR ANY
WETTING RAINFALL WILL REMAIN OVER THE HIGHER TERRAIN OF EASTERN
AND SOUTHEASTERN AZ. AFTERNOON MINIMUM HUMIDITIES WILL RANGE FROM
7-15% ACROSS SOUTHEAST CA AND BETWEEN 20-35% FOR THE THE AZ
DESERTS TODAY AND WILL LIKELY INCREASE ABOVE 25% AREAWIDE THIS
WEEKEND. OVERNIGHT RECOVERIES WILL RANGE FROM POOR ACROSS THE
WESTERN DESERTS TO GOOD ACROSS THE EASTERN DISTRICTS TONIGHT AND
INCREASE TO GOOD AREAWIDE THIS WEEKEND. 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 THIS AFTERNOON/EARLY EVENING. LIGHTER WINDS,
GENERALLY AROUND 15 MPH OR LESS WILL TRANSPIRE THIS WEEKEND.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...SALERNO
LONG TERM...SALERNO
AVIATION...BENEDICT
FIRE WEATHER...SALERNO
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