715
FXUS65 KPSR 272219
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
319 PM MST WED AUG 27 2025
KEY MESSAGES
- ISOLATED SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THIS
AFTERNOON INTO THE EVENING AREAWIDE WITH LIGHT SHOWER ACTIVITY
THEN AFFECTING SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA
TONIGHT THROUGH THURSDAY AFTERNOON.
- TEMPERATURES THURSDAY WILL RANGE FROM NEAR NORMAL ACROSS SOUTH-
CENTRAL ARIZONA TO BELOW NORMAL ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. WIDESPREAD MODERATE HEAT RISK IS EXPECTED
FOR THIS WEEKEND.
- OVERALL DRY CONDITIONS WILL PREVAIL LATER THIS WEEK AND LIKELY
THROUGH THE WEEKEND BEFORE RAIN CHANCES GRADUALLY INCREASE
DURING THE FIRST HALF OF NEXT WEEK.
SHORT TERM /TODAY THROUGH THURSDAY/
EARLY AFTERNOON RAP ANALYSIS SHOWED A WEAK PACIFIC TROUGH OFF THE
CALIFORNIA COAST, WHICH HAS PROMOTED DRIER SOUTHWESTERLY FLOW ALOFT
OVER MUCH OF OUR REGION. TODAY'S 18Z YUMA SOUNDING AND 12Z PHOENIX
SOUNDING SHOWED CONSIDERABLE DRY AIR ABOVE 500 MB WITH PWATS NOW
AROUND 1.2-1.5". MEANWHILE LOOKING FURTHER TO THE SOUTH, VISIBLE
SATELLITE AND WV IMAGERY SHOW TROPICAL STORM JULIETTE ADVANCING
NORTHWARD, WHICH WILL HELP TO BRING IN BETTER MOISTURE ALOFT.
LATEST RADAR EARLY THIS AFTERNOON SHOWED ISOLATED SHOWERS AND
THUNDERSTORMS DEVELOPING ACROSS PARTS OF THE FORECAST AREA,
INCLUDING AREAS SUCH AS DESERT CENTER IN SOUTHEAST CALIFORNIA
OVER TO AREAS IN SOUTHERN GILA COUNTY. THIS ACTIVITY WILL CONTINUE
TO REMAIN ISOLATED THROUGH THE AFTERNOON WITH SOME GUSTY OUTFLOW
WINDS POSSIBLE. AS MENTIONED BEFORE, TROPICAL STORM JULIETTE WILL
CONTINUE TO ADVANCE NORTHWARD WHILE WEAKENING AND WILL BRING US
INCREASING MID AND UPPER LEVEL MOISTURE THIS EVENING INTO
THURSDAY, PARTICULARLY FOR THE WESTERN PART OF OUR AREA. WITH
THIS INCREASE IN MOISTURE ALOFT, GUIDANCE SHOW PWATS RISING TO
UPWARDS OF AROUND 1.5-1.8" ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA WITH LOWER VALUES ANTICIPATED TO THE EAST ACROSS
SOUTH- CENTRAL ARIZONA. GIVEN THIS INCREASE IN MOISTURE ALONG
WITH SOME EXPECTED UPPER FORCING, HI- RES GUIDANCE SHOW A LIGHT
BAND OF SHOWER ACTIVITY DEVELOPING TONIGHT AND PERSISTING INTO
TOMORROW OVER SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA. THIS
SHOWER ACTIVITY IS EXPECTED TO PERSIST THROUGH THE MORNING AND
INTO THE AFTERNOON TOMORROW AS THE AFOREMENTIONED WEAK PACIFIC
TROUGH PULLS THE REMNANTS OF JULIETTE NORTHEASTWARD INTO THE
DESERT SOUTHWEST. THIS SHOWER ACTIVITY IS LARGELY EXPECTED TO
REMAIN WEST OF THE PHOENIX AREA WITH AREAS ACROSS SOUTH-CENTRAL
ARIZONA PRIMARILY SEEING THICKER MID AND HIGH LEVEL CLOUD COVER.
RAINFALL AMOUNTS WITH THE SHOWER ACTIVITY TO THE WEST WILL MOSTLY
REMAIN ON THE LIGHT SIDE BEFORE SHOWERS PUSH OUT OF THE AREA BY
THURSDAY EVENING.
CURRENT NBM TEMPERATURES SHOW HIGHS FOR THURSDAY TOPPING OUT AROUND
100-103 DEGREES ACROSS THE VALLEY, WHILE AREAS OUT WEST ARE FORECAST
TO ONLY SEE HIGHS IN THE LOWER TO MID 90S. DEPENDING ON HOW MUCH
SHOWER ACTIVITY THESE AREAS SEE, THESE TEMPERATURES COULD END UP
BEING A BIT LOWER.
LONG TERM /FRIDAY THROUGH TUESDAY/
BY FRIDAY, THE REMNANT MOISTURE FROM TC JULIETTE IS EXPECTED TO
SHIFT OUT OF THE REGION WITH DRIER WESTERLY FLOW TAKING OVER AS
THE SUBTROPICAL RIDGE CENTERED NEAR EL PASO BECOMES THE MAIN
DRIVER OF OUR WEATHER. WE SHOULD RETURN TO FULL SUNSHINE ON FRIDAY
WITH BOUNDARY LAYER MOISTURE GRADUALLY GETTING MIXED OUT,
LOWERING SURFACE DEW POINTS DOWN INTO THE LOW 50S AND THEN INTO
THE MID TO UPPER 40S ON SATURDAY. THE RIDGE WILL BRING SOME
INCREASING HEIGHTS OVER THE REGION FRIDAY INTO THE WEEKEND AND
HELPING TO BRING HOTTER CONDITIONS AS HIGHS WARM TO JUST ABOVE
NORMAL STARTING SATURDAY. WE ARE EXPECTING TO SEE WIDESPREAD
MODERATE HEATRISK DEVELOP BY SATURDAY AND POSSIBLY SOME VERY
LOCALIZED MAJOR HEATRISK ON SUNDAY AS SOME OF THE LOWER DESERTS
COULD TOP OUT NEAR 110 DEGREES.
EVENTUALLY ENSEMBLE GUIDANCE SHOWS THE RIDGE CENTER SHIFTING
NORTHWARD TO OVER OR NEAR NORTHERN ARIZONA EARLY NEXT WEEK
ALLOWING SOME WEAK SOUTHEASTERLY MOIST FLOW BACK INTO AT LEAST
SOUTHERN ARIZONA. THERE IS STILL A GOOD DEAL OF UNCERTAINTY WITH
THE TIMING OF THE MOISTURE RETURN AND THE NBM TRIES TO EVEN
INTRODUCE SLIGHT CHANCE POPS ALREADY ON SUNDAY, BUT THAT SEEMS TOO
EARLY. OUR THINKING IS WE MAY SEE SOME HIGH TERRAIN CONVECTION
RETURN BY MONDAY AND THEN POTENTIALLY INTO THE LOWER DESERTS
AROUND NEXT TUESDAY OR WEDNESDAY. TEMPERATURES EARLY NEXT WEEK ARE
LIKELY TO START TO TREND DOWNWARD WITH THE INCREASE IN MOISTURE,
BUT MORE THAN LIKELY WILL REMAIN AT LEAST A COUPLE DEGREES ABOVE
NORMAL INTO THE MIDDLE PART OF NEXT WEEK.
AVIATION
UPDATED AT 1750Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
WINDS WILL BE WESTERLY EARLY THIS AFTERNOON (18-20Z), WITH A
LATER THAN NORMAL SWITCH TO EASTERLY DURING THE OVERNIGHT HOURS.
WIND SPEEDS ARE EXPECTED TO BE AOB 10 KT THROUGH THE PERIOD. ANY
SHOWERS OR STORMS THAT DEVELOP TODAY ARE EXPECTED TO REMAIN AWAY
FROM THE PHOENIX METRO AND OVER HIGHER TERRAIN AREAS. INCREASING
MID AND HIGH LEVEL CLOUDS ARE ANTICIPATED THROUGH THE PERIOD.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
WINDS OVERALL WILL FAVOR THEIR DIURNAL TENDENCIES THIS AFTERNOON
SWITCHING TO SW'RLY THIS EVENING). SPEEDS WILL GENERALLY BE AOB 10
KT THROUGH THE PERIOD. CONFIDENCE FOR THE ARRIVAL OF -SHRA AFTER
12Z IS AROUND 50-70%, WILL SEE INCREASING CLOUD COVER THROUGH THE
TAF PERIOD WITH CLOUD BASES FALLING TO 9-10 KFT DURING LIGHT RAIN
SHOWERS, EXPECT WINDS AOB 10-15 KTS WITH GUSTS UP TO 20-25 KTS
TOWARDS THE LATTER PART OF THE FORECAST PERIOD AS THE SYSTEM MOVES
OUT.
FIRE WEATHER
CHANCES FOR SHOWERS AND THUNDERSTORMS WILL OVERALL REMAIN LOW (20%
OR LESS) ACROSS SOUTH-CENTRAL ARIZONA OVER THE NEXT COUPLE OF
DAYS, WHILE THE BEST CHANCES ARE EXPECTED ACROSS THE WESTERN
DISTRICTS THROUGH TOMORROW AFTERNOON. PRIMARY THREAT WITH ANY
THUNDERSTORMS THIS AFTERNOON WILL BE GUSTY, ERRATIC OUTFLOW WINDS.
RAIN CHANCES DROP BELOW 10% BY FRIDAY WITH DRIER CONDITIONS
PREVAILING. MINRHS OVER THE NEXT COUPLE OF DAYS WILL MOSTLY RANGE
BETWEEN 20-30% BEFORE GRADUALLY DECREASING INTO THE TEENS BY THE
WEEKEND. TEMPERATURES WILL REMAIN NEAR TO SLIGHTLY BELOW NORMAL
THROUGH THURSDAY BEFORE RISING TO SLIGHTLY ABOVE NORMAL BY
SATURDAY. CHANCES FOR MONSOONAL ACTIVITY INCREASE AGAIN GOING INTO
NEXT WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...SMITH
LONG TERM...KUHLMAN
AVIATION...BERISLAVICH/95
FIRE WEATHER...SMITH/KUHLMAN
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