856
FXUS65 KPSR 041125
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
425 AM MST FRI SEP 4 2026
UPDATE
UPDATED 12Z 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 1125Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE LIKELIHOOD OF ANOTHER SLOW TRANSITION TO WESTERLY WINDS WITH A
PERIOD OF GUSTY SOUTH CROSS RUNWAY WINDS AND THEN THE SLIGHT
(10-20%) POSSIBILITY OF TSRA/SHRA THIS AFTERNOON AND EARLY EVENING
WILL BE THE MAIN WEATHER ISSUES THIS TAF PERIOD. CURRENT SE'RLY
WINDS ARE EXPECTED TO SLOWLY TRANSITION TO W'RLY/SW'RLY WINDS THIS
AFTERNOON. THE SLOW TRANSITION WILL CAUSE A PERIOD OF S'RLY
CROSSWINDS (150V230), AND SOME OCCASIONAL GUSTS IN THE UPPER TEENS
DURING THIS TIME WILL ALSO BE POSSIBLE. ONCE W'RLY WINDS DEVELOP
THIS AFTERNOON, OCCASIONAL GUSTS INTO THE UPPER TEENS WILL
CONTINUE TO BE POSSIBLE THROUGH THE EARLY EVENING. CHANCES FOR
TSRA/SHRA LATE THIS AFTERNOON AND EVENING ARE TOO LOW (10-20%) TO
INCLUDE IN THIS TAF PACKAGE. WINDS ARE THEN EXPECTED TO BE W'RLY
INTO THE OVERNIGHT HOURS BEFORE DEVELOPING THEIR USUAL E'RLY
COMPONENT DURING THE OVERNIGHT HOURS. SCT MID AND HIGH CLOUDS WILL
BECOME BKN AT TIMES THIS AFTERNOON BEFORE GRADUALLY CLEARING OUT
THIS EVENING AND OVERNIGHT.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
OCCASIONAL LATE AFTERNOON/EARLY EVENING GUSTY WINDS WILL BE THE
MAIN WEATHER ISSUE THROUGH THE TAF PERIOD UNDER MOSTLY CLEAR
SKIES, WITH FEW HIGH CLOUDS STARTING TO MOVE IN AT THE END OF THE
TAF PERIOD. SW GUSTS 20-25KT WILL BE COMMON AT KBLH LATE
AFTERNOON WHILE KIPL SHOULD EXPERIENCE THE MOST PRONOUNCED GUSTS
DURING THE EVENING. SPEEDS WILL RELAX OVERNIGHT AND EARLY MORNING
WHERE BRIEF PERIODS OF NEARLY CALM CONDITIONS WILL EXIST.
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...BERISLAVICH/18
FIRE WEATHER...SALERNO
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