729
FXUS65 KPSR 252052
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
152 PM MST MON AUG 25 2025
KEY MESSAGES
- A FLOOD WATCH IS IN EFFECT FOR MUCH OF SOUTHWEST ARIZONA AND
SOUTHEAST CALIFORNIA THIS AFTERNOON AND EVENING, AS SOME
THUNDERSTORMS WILL BE CAPABLE OF PRODUCING HEAVY RAINFALL AND
LOCALIZED FLOODING.
- SHOWERS AND THUNDERSTORMS ARE LIKELY OVER MUCH OF THE AREA
TODAY AND POSSIBLY AGAIN ON TUESDAY. GUSTY WINDS, BLOWING DUST,
HEAVY RAINFALL, AND LOCALIZED FLOODING WILL ALL BE POSSIBLE,
ESPECIALLY THROUGH THIS EVENING.
- TEMPERATURES COOL OFF OVER THE NEXT COUPLE DAYS, DROPPING TO
BELOW NORMAL STARTING TUESDAY.
- DRYING CONDITIONS DURING THE LATTER HALF THE WEEK WILL GREATLY
DIMINISH RAIN CHANCES ACROSS THE AREA, WITH ACTIVITY LIKELY
BECOMING CONFINED TO HIGH TERRAIN EAST OF PHOENIX BY THE END OF
THE WEEK.
SHORT TERM /TODAY THROUGH TUESDAY/
THE MAIN FORECAST CONCERN FOR THE NEXT DAY OR TWO REMAINS THE
POTENTIAL FOR HEAVY RAINFALL AND LOCALIZED FLASH FLOODING, AS
MOISTURE INCREASES AND UPPER LEVEL FORCING HAS BECOME FAVORABLE WITH
A PACIFIC TROUGH APPROACHING THE REGION. CONVERGENCE AT THE LOW TO
MID LEVELS WAS SEEN THIS MORNING, WITH SHOWERS AND STORMS TRAINING
ALONG A SSE TO NNW ORIENTED LINE THROUGH YUMA AND LA PAZ COUNTIES,
AND THIS LINE OF CONVERGENCE HAS BEGUN TO SHIFT EASTWARD EARLY THIS
AFTERNOON, PERHAPS INFLUENCING THE DEVELOPMENT OF STORMS OVER SOUTH-
CENTRAL AZ LATER THIS AFTERNOON INTO THE EVENING. UPPER LEVEL
DIFFLUENCE IS APPARENT IN OBJECTIVE ANALYSIS, AS THE EXIT REGION OF
A JET WRAPPING AROUND THE BASE OF THE AFOREMENTIONED PACIFIC TROUGH
MOVES OVER THE REGION. LATEST HREF GUIDANCE ALSO REVEALS 10-30%
NEIGHBORHOOD PROBABILITIES FOR WIND GUSTS IN EXCESS OF 58 MPH THIS
AFTERNOON INTO THE EARLY EVENING, FOCUSED ACROSS PORTIONS OF SE CA
AND SOUTHERN INTO SOUTH-CENTRAL AZ. AS SUCH, BLOWING DUST IS
EXPECTED TO BE A CONCERN ACROSS THE TYPICALLY PRONE LOWER DESERT
LOCATIONS.
RAP ANALYZED PRECIPITABLE WATER HAS REACHED WIDESPREAD VALUES IN
EXCESS OF 1.6-1.7" ACROSS SOUTHWEST AZ AS DEEP SOUTHERLY MOIST FLOW
CONTINUES TO STREAM OVER THE AREA. CUMULUS FIELDS AND A FEW ISOLATED
STORMS HAVE ALREADY DEVELOPED ALONG THE INTERNATIONAL BORDER EARLY
THIS AFTERNOON, PERHAPS A BIT SOONER THAN INITIALLY ANTICIPATED FOR
AREAS IN SOUTHERN YUMA COUNTY CONSIDERING AN MCV HAS PASSED THROUGH
SOUTHWEST AZ THIS MORNING AND IS NOW APPROXIMATELY OVER THE SOUTHERN
TIP OF NEVADA. DESTABILIZATION UNDER CLEAR SKIES HAS BEEN QUITE
RAPID, WITH 100 MB MLCAPE VALUES ALREADY UP TO 1000-1500 J/KG, AND
WITH DCAPE VALUES APPROACHING THOSE LEVELS, IT WILL NOT BE DIFFICULT
TO REALIZE SEVERE WIND GUSTS WITH ANY STORMS THAT DO FORM.
MEANWHILE, THERMODYNAMIC PROFILES (REFERENCING KYUM GFS BUFR
SOUNDINGS) LOOK EXCELLENT, WITH BARELY ANY INHIBITION, 7-8 KFT CLOUD
DEPTHS BELOW THE FREEZING LEVEL, AND MIDLEVEL RHS AROUND 75%,
INDICATING THAT EFFICIENT (WARM) RAINFALL PROCESSES WILL BE
PREVALENT WITH THE ACTIVITY THIS AFTERNOON. ANY STRONG UPDRAFT
WILL BE CAPABLE OF PRODUCING 1-2" OF RAIN IN A RELATIVELY SHORT
AMOUNT OF TIME, LEADING TO THE ANTICIPATED FLASH FLOOD THREAT. ACTIVITY
IS EXPECT TO TREND NORTHWARD THROUGH THE REST OF THE DAY,
GENERALLY CLOSING IN FROM THE SOUTHWEST IN SE CA AND FAR SW AZ AND
FROM THE SOUTHEAST WITH A COMPLEX OF STORMS ANTICIPATED TO
DEVELOP NEAR TUCSON.
BY LATE THIS EVENING INTO TONIGHT, GUIDANCE GENERALLY AGREES ON A
DIMINISHING THREAT FOR SHOWER AND THUNDERSTORM ACTIVITY. FORECAST
UNCERTAINTY INCREASES FURTHER FOR TUESDAY AS WE ARE LIKELY TO BE
UNDER A SCENARIO WHERE WE HAVE WORKED OVER THE ATMOSPHERE A GOOD
DEAL TODAY LEAVING LESS INSTABILITY FOR TUESDAY. THERE IS ALSO
DIFFERENCES IN THE AMOUNT OF MOISTURE AVAILABLE FOR TUESDAY WITH THE
GEFS INDICATING SOME DRYING ALREADY OCCURRING WHILE THE EPS KEEPS
THE 1.5-1.7" PWATS IN PLACE. NBM POPS ALSO SEEM WAY OUT OF WHACK FOR
TUESDAY PROVIDING HIGHER CHANCES ON TUESDAY VERSUS TODAY. WE HAVE
LOWERED POPS TUESDAY TO MOSTLY SHOW 30-50% CHANCES ACROSS THE LOWER
DESERTS TO 50-70% OVER THE EASTERN ARIZONA HIGHER TERRAIN. TUESDAY
MAY END UP PLAYING OUT WELL FOR THOSE AREAS THAT DO NOT RECEIVE MUCH
CONVECTION TODAY, SPECIFICALLY FROM PHOENIX AND AREAS TO THE EAST OF
PHOENIX. WE ALSO CAN'T RULE OUT A THREAT FOR HEAVY RAINFALL AND
LOCALIZED FLOODING ON TUESDAY FOCUSED MORE OVER THE EASTERN PORTION
OF THE REGION.
TEMPERATURES TODAY WILL DROP FROM WHAT WE SAW OVER THE WEEKEND, BUT
DAYTIME HIGHS TODAY ARE LIKELY TO STILL REACH TO WITHIN A DEGREE OR
TWO OF NORMALS. THE INCREASED MOISTURE AND RAIN COOLED AIR SHOULD
BRING DOWN TEMPERATURES FURTHER FOR TUESDAY WITH HIGHS ANYWHERE FROM
THE MID 90S TO AROUND 100 DEGREES.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
BY WEDNESDAY, THE INFLUENCES OF THE SUBTROPICAL HIGH WILL BE MUCH
LESS AS IT SHIFTS ITS CENTER OVER THE SOUTHERN PLAINS. AT THE SAME
TIME, THE PACIFIC TROUGH WILL NUDGE INTO AT LEAST WESTERN
PORTIONS OF OUR REGION LEADING TO LOWER HEIGHTS AND TURNING OUR
FLOW OUT OF THE SOUTHWEST. THIS WILL BRING IN A GOOD AMOUNT OF
DRIER AIR WEDNESDAY INTO THURSDAY, EVENTUALLY SCOURING OUT MUCH OF
OUR LOW LEVEL MOISTURE BY FRIDAY. HOWEVER, THE LINGERING MOISTURE
ON WEDNESDAY SHOULD STILL BE ENOUGH TO ALLOW FOR SOME ISOLATED
SHOWER AND THUNDERSTORM ACTIVITY LIKELY FOCUSED OVER HIGHER
TERRAIN AREAS. AS THE DRY AIR REALLY SETTLES IN BY THURSDAY, WE
SHOULD EXPECT ONLY VERY MINIMAL RAIN CHANCES ACROSS THE EASTERN
ARIZONA HIGH TERRAIN. THIS WESTERLY FLOW DRY PATTERN IS LIKELY TO
CONTINUE THROUGH THE UPCOMING WEEKEND KEEPING MUCH IF NOT ALL OF
OUR AREA DRY.
TEMPERATURES SHOULD CONTINUE TO RUN SLIGHTLY BELOW NORMAL FOR
WEDNESDAY AND THURSDAY BEFORE SOME GRADUAL WARMING PUSHES HIGHS
BACK INTO THE NORMAL RANGE OF 102-105 DEGREES BY FRIDAY.
ADDITIONAL WARMING IS FAVORED OVER THE WEEKEND AS THE SUBTROPICAL
HIGH SOMEWHAT NUDGES BACK INTO OUR REGION. THE NBM SUGGESTS
DAYTIME HIGHS WARMING BACK TO BETWEEN 104-108 DEGREE RANGE FOR
THE WEEKEND.
AVIATION
UPDATED AT 1720Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
CONFIDENCE CONTINUES TO INCREASE FOR IMPACTS FROM THUNDERSTORMS
LATER THIS AFTERNOON INTO THE EVENING AT VALLEY TERMINALS. A
COMPLEX OF THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS SOUTHERN
AZ THIS AFTERNOON AND LIFT NORTH ACROSS THE VALLEY BY EARLY
EVENING. THESE STORMS WILL PUSH OUT A STRONG OUTFLOW FROM THE
SOUTH WITH A GENERAL TIMING OF THE INITIAL GUSTY WIND SHIFT
EXPECTED BETWEEN 23Z-01Z. BLOWING DUST IS ANTICIPATED WITH THIS
OUTFLOW DUE TO THE FAVORABLE SSE DIRECTION REDUCING SURFACE AND
SLANTWISE VISIBILITIES. THIS ENTIRE COMPLEX OF STORMS WILL LIKELY
(40-60%) SHIFT INTO THE VALLEY. HAVE ADDED TEMPO GROUP FOR
THUNDERSTORMS AT ALL TERMINALS, GENERALLY IN THE 01Z-05Z
TIMEFRAME. SOME SHOWERS WILL LINGER INTO OVERNIGHT WITH LINGERING
SCT/BKN CLOUD COVER.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
SHRA/TSRA WITH GUSTY WINDS WILL BE THE PRIMARY HAZARD TO
OPERATIONS THROUGH TONIGHT UNDER PERIODS OF MID/HIGH CIGS ABOVE 8K
FT AGL. CONFIDENCE IS FAIR THAT ANOTHER ROUND OF TSRA SIMILAR TO
YESTERDAY WILL DEVELOP THIS AFTERNOON SOUTH AND WEST OF KIPL.
GUSTY WINDS WITH BLOWING DUST AND LOCALLY HEAVY RAINFALL ARE
POSSIBLE BEFORE LIFTING AWAY FROM THE AREA IN THE EVENING, MAINLY
IN THE 22-01Z TIMEFRAME.
FIRE WEATHER
ABUNDANT MOISTURE AND PERIODS OF SHOWERS AND THUNDERSTORMS ARE
EXPECTED EARLY THIS WEEK. THE BEST RAINFALL CHANCES TODAY ARE
LIKELY TO BE FOCUSED ACROSS THE WESTERN DISTRICTS BEFORE SHIFTING
OVER THE EASTERN DISTRICTS ON TUESDAY. STRONG GUSTY WINDS, HEAVY
RAINFALL AND LOCALIZED FLOODING WILL BE POSSIBLE, ESPECIALLY
TODAY. ELEVATED HUMIDITIES WILL LEAD TO MINRHS BETWEEN 25-40%
TODAY AND TUESDAY BEFORE GRADUALLY LOWERING BEGINNING WEDNESDAY.
TEMPERATURES WILL DROP INTO THE NORMAL RANGE TODAY AND TO BELOW
NORMAL STARTING TUESDAY. DRYING CONDITIONS LATER THIS WEEK SHOULD
MOSTLY END RAIN CHANCES BY THURSDAY WITH MINRHS DROPPING BACK INTO
THE TEENS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...FLOOD WATCH UNTIL 9 PM MST THIS EVENING FOR AZZ530>533-535-536-
539-559.
BLOWING DUST ADVISORY UNTIL 7 PM MST THIS EVENING FOR AZZ539-551-
553-554-559.
CA...FLOOD WATCH UNTIL 9 PM PDT THIS EVENING FOR CAZ562>567-569-570.
SHORT TERM...WHITTOCK
LONG TERM...KUHLMAN
AVIATION...FRIEDERS
FIRE WEATHER...KUHLMAN
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