065
FXUS65 KPSR 282152
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
252 PM MST MON JUL 28 2025
UPDATE
UPDATED SHORT TERM DISCUSSION.
KEY MESSAGES
- WIDESPREAD MODERATE HEATRISK WITH LOWER DESERT HIGH TEMPERATURES
AROUND 110 DEGREES WILL BE COMMON EACH DAY THIS WEEK.
- AN INCREASE IN MOISTURE WILL INCREASE SHOWER AND THUNDERSTORM
ACTIVITY FOR EASTERN PORTIONS OF ARIZONA TODAY AND TUESDAY, WITH
SLIGHT CHANCES THEN SPREADING INTO SOUTH-CENTRAL ARIZONA
WEDNESDAY INTO THURSDAY.
SHORT TERM /TODAY THROUGH TUESDAY/
A VERY DRY AIRMASS REMAINS IN PLACE ACROSS MOST OF AZ AND SOCAL,
BUT A FLUX OF MOISTURE INTO THE SOUTHEASTERN PART OF AZ (PWATS
BACK TO AND ABOVE 1") WILL LEAD TO SPOTTY SHOWERS AND STORMS THIS
AFTERNOON AND EVENING, INCLUDING SLIGHT CHANCE POPS 10-30% IN
PARTS OF SOUTHERN GILA COUNTY. HIGH T-TD SPREADS IS YIELDING HIGH
DCAPE VALUES, IN EXCESS OF 1000 J/KG, SO STRONG GUSTY WINDS ARE
ANTICIPATED WITH ANY STORM THIS AFTERNOON. THE LATEST HREF HAS A
NEIGHBORHOOD PROBABILITY FOR CONVECTIVE WINDS >35 MPH AS HIGH AS
70% NEAR THE AZ/NM BORDER. THERE IS POTENTIAL FOR AN OUTFLOW, OR
COUPLE OF OUTFLOWS, TO MAKE IT ALL THE WAY TO PHOENIX VALLEY THIS
EVENING, BUT ASIDE FROM PERHAPS SOME LOCALIZED GUSTS UP TO 20-25
MPH ANY OUTFLOW WILL MOSTLY JUST INDUCE A WIND SHIFT. MEAN PBL
MIXING RATIOS ARE STILL PRETTY LOW, <8 G/KG, IN SOUTHERN GILA
COUNTY, SO FLASH FLOODING IS A VERY LOW RISK TODAY.
THE TEMPERATURE AT PHOENIX SKY HARBOR HAS ALREADY HIT 110 DEGREES
THIS AFTERNOON, WHICH BRINGS THE ANNUAL 110+ TALLY TO 18 DAYS
NOW, WHILE THIS COUNT IS 5 DAYS ABOVE NORMAL THROUGH JULY 28TH IT
IS ONLY HALF AS MANY AS THE PAST COUPLE YEARS - 2024 (38 DAYS) &
2023 (32 DAYS). ABOVE NORMAL H5 HEIGHTS AT 593-595DAM IS HELPING
DRIVE THESE ABOVE NORMAL TEMPERATURES IN PHOENIX AND ACROSS THE
REGION. WE COULD BE IN AN EXTREME HEAT EPISODE, WITH TEMPERATURES
SEVERAL DEGREES HOTTER, IF IT WERE NOT FOR THE PREPONDERANCE OF
TROUGHING ALONG THE WEST COAST AND DRIER AIR KEEPING OVERNIGHT LOW
TEMPERATURES ON THE MORE SEASONAL TO SUB-SEASONAL SIDE.
REGARDLESS, THE TEMPERATURES TODAY ARE LEADING TO WIDESPREAD
MODERATE HEATRISK (LEVEL 2 OF 4).
THERE WILL BE VERY LIMITED CHANGES TO THE OVERALL PATTERN AND
ENVIRONMENT HEADING INTO TUESDAY, ASIDE FROM MOISTURE SPREADING A
LITTLE FURTHER WEST IN AZ. AS A RESULT TEMPERATURES TUESDAY WILL
BE SIMILAR TO TODAY AND SHOWERS AND STORMS WILL AGAIN BE CONFINED
PRIMARILY TO SOUTHEAST AZ, WITH 10-30% POPS AGAIN IN SOUTHERN GILA
COUNTY.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
GUIDANCE IS STARTING TO AGREE MORE WITH WHAT MAY HAPPEN FOR THE
LATTER HALF OF THE WEEK. BOTH THE GEFS AND THE EPS MOSTLY AGREE ON
CONTINUED MOISTURE ADVECTING INTO THE AREA FROM THE EAST. THE MAIN
UNCERTAINTY BETWEEN THE TWO ENSEMBLES IS HOW FAR WEST THE MOISTURE
PUSHES, WITH THE GEFS HAVING MOISTURE PUSH FURTHER WEST AND EPS
HOLDING ONTO THE DRIER AIR UNTIL THURSDAY FOR SOUTH-CENTRAL AZ.
THIS SHOULD BRING SHOWER AND THUNDERSTORM CHANCES AS FAR WEST AS
MARICOPA COUNTY ON WEDNESDAY, BUT WITH LOW LEVEL MIXING RATIOS
ONLY LIKELY REACHING 8-9 G/KG STORM COVERAGE ON WEDNESDAY SHOULD
BE FAIRLY LIMITED OVER THE LOWER DESERTS. FORECAST SOUNDINGS FOR
WEDNESDAY DO SHOW IMPROVING MUCAPE TO AROUND 500 J/KG INTO THE
LOWER DESERTS, WHILE DCAPE WILL BE QUITE HIGH AT AROUND 1500 J/KG.
THIS SHOULD AT LEAST POSE A VERY LOCALIZED THREAT FOR STRONG
WINDS ACROSS THE AREA.
MOISTURE SHOULD CONTINUE TO INCREASE AND REACH ITS PEAK DURING
BY THE END OF THE DAY THURSDAY. FORECAST PWATS ON THURSDAY ARE
SEEN REACHING BETWEEN 1.2-1.4" WITH MORE ADEQUATE LOW LEVEL MIXING
RATIOS OF 10-11 G/KG. THIS SHOULD BOOST MUCAPE CLOSER TO 1000
J/KG AND ALLOW FOR BETTER CHANCES FOR LOWER DESERT THUNDERSTORM
ACTIVITY THURSDAY AFTERNOON AND EVENING. HOWEVER, AN OVERALL WEAK
SOUTH TO SOUTHWEST STEERING FLOW AND LITTLE TO NO UPPER LEVEL
SUPPORT IS LIKELY TO PRECLUDE ANY ORGANIZED STORM CLUSTERS FROM
OCCURRING. POTENTIAL STORM THREATS THURSDAY WILL AGAIN LEAN TOWARD
STRONG GUSTY WINDS/BLOWING DUST, BUT WITH THE IMPROVED MOISTURE
THERE MAY ALSO BE A VERY LOCALIZED HEAVY RAINFALL/FLOOD THREAT.
NBM POPS ALSO REACH THEIR PEAK ON THURSDAY AT 20-30% ACROSS THE
SOUTH-CENTRAL ARIZONA LOWER DESERTS.
STARTING THURSDAY NIGHT, THE FLOW PATTERN IS EXPECTED TO SHIFT
OUR WINDS MORE OUT OF THE WEST SOUTHWEST AS GUIDANCE SHOWS THE
SUBTROPICAL RIDGE CENTER MOVING SOMEWHERE ACROSS SOUTHWEST NEW
MEXICO, SOUTHEAST ARIZONA, OR OVER SONORA. ASSUMING THIS OCCURS,
IT WOULD BRING A QUICK DRYING TREND ON FRIDAY WITH LOWER DESERT
RAIN CHANCES DROPPING TO AROUND 10% AND TO 20-30% OVER THE EASTERN
ARIZONA HIGH TERRAIN. THIS PATTERN IS THEN LIKELY TO HOLD THROUGH
THE WEEKEND, ENDING RAIN CHANCES ACROSS THE LOWER DESERTS
COMPLETELY AND ONLY ALLOWING VERY LIMITED CHANCES OVER HIGHER
TERRAIN AREAS.
AVIATION
UPDATED AT 1830Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
CONFIDENCE IS GOOD THAT WINDS WILL CONTINUE TO FOLLOW THEIR
TYPICAL DIURNAL TENDENCIES THROUGH TUESDAY AFTERNOON. WINDS
SHOULD HAVE LIMITED GUSTINESS THIS AFTERNOON AFTER THE W/SW WIND
SHIFT AROUND 19-20Z. THUNDERSTORMS WILL REMAIN RELEGATED TO FAR
EASTERN ARIZONA, HOWEVER, CONFIDENCE IS MODERATE THAT DISTANT
OUTFLOWS WILL BE MAINTAINED INTO THE PHOENIX AIRSPACE SUCH THAT AN
EARLIER THAN USUAL, AND POSSIBLY ABRUPT WIND SHIFT WILL SWEEP
ACROSS AERODROMES LATE THIS EVENING (05-07Z). PERIODS OF
OCCASIONAL MID/HIGH CLOUD DECKS WILL CONTINUE.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO WEATHER CONCERNS WILL EXIST THROUGH TUESDAY MORNING UNDER
MOSTLY CLEAR SKIES. WINDS AT KIPL WILL EXHIBIT PERIODS OF
VARIABILITY BUT OVERALL FAVOR SE THEN W DURING THE EVENING INTO
THE OVERNIGHT HOURS. AT KBLH, WINDS WILL OVERALL FAVOR S BUT TEND
TOWARDS SW DURING THE EVENING. SPEEDS WILL GENERALLY REMAIN AOB 11
KTS, WITH MINIMAL AFTERNOON/EVENING GUSTINESS.
FIRE WEATHER
CHANCES FOR SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL RETURN
TO THE HIGH TERRAIN EAST OF PHOENIX BEGINNING THIS AFTERNOON,
WITH HIGHER CHANCES AND COVERAGE EXTENDING INTO THE LOWER DESERTS
WEDNESDAY AND PEAKING THURSDAY. THE NEXT COUPLE OF DAYS WILL ALSO
POSE AT LEAST A MINOR RISK OF DRY LIGHTNING ACROSS GILA COUNTY.
AFTERNOON MINRHS FOR THE LOWER DESERTS WILL REMAIN BETWEEN 5-15%
TODAY THROUGH WEDNESDAY, WITH 15-20% IN SOUTHERN GILA COUNTY.
MINRHS PEAK AROUND 15-25% ACROSS THE REGION THURSDAY BEFORE DRYING
AGAIN. OUTSIDE OF THE INFLUENCE OF THUNDERSTORMS, WINDS WILL
GENERALLY FOLLOW DIURNAL TENDENCIES WITH TYPICAL AFTERNOON UPSLOPE
GUSTINESS. TEMPERATURES WILL MOSTLY RUN 3-6 DEGREES ABOVE NORMAL
OVER THE NEXT SEVERAL DAYS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...BENEDICT
LONG TERM...KUHLMAN/BENEDICT
AVIATION...WHITTOCK/BERISLAVICH
FIRE WEATHER...KUHLMAN/BENEDICT
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