181
FXUS65 KPSR 290500
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1000 PM MST MON JUL 28 2025
UPDATE
UPDATED AVIATION
KEY MESSAGES
- WIDESPREAD MODERATE HEATRISK WITH LOWER DESERT HIGH TEMPERATURES
AROUND 110 DEGREES THIS WEEK.
- INCREASING MOISTURE WILL RESULT IN BETTER SHOWER AND THUNDERSTORM
CHANCES FOR EASTERN PORTIONS OF ARIZONA TODAY AND TUESDAY, THEN
CHANCES 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 0500Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO SIGNIFICANT WEATHER ISSUES WILL EXIST THROUGH TUESDAY NIGHT UNDER
OCCASIONAL PERIODS OF MID/HIGH CLOUD DECKS. EAST WINDS WILL
EVENTUALLY SETTLE OVER THE AREA AFTER MIDNIGHT WITH DISTANT OUTFLOWS
SLOWLY PROGRESSING INTO THE AIRSPACE. THUNDERSTORMS WILL REMAIN
RELEGATED TO FAR EASTERN ARIZONA AGAIN TUESDAY AFTERNOON/EVENING
WITH OUTFLOWS TRYING TO PUSH WESTWARD. CONFIDENCE IS MODERATE
REGARDING TIMING OF WIND SHIFTS TUESDAY EVENING/OVERNIGHT AS
DECAYING OUTFLOWS MAY INFLUENCE AND HASTEN THE TYPICAL NOCTURNAL
EASTERLY SHIFT, OR COULD DISSIPATE PRIOR TO REACHING THE AERODROMES.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO WEATHER CONCERNS WILL EXIST THROUGH TUESDAY NIGHT UNDER CLEAR
SKIES. TRENDS IN WINDS WILL REMAIN SIMILAR TO THE PAST 24 HOURS
INCORPORATING LIMITED GUSTINESS AND EXTENDED PERIODS OF NEARLY CALM
CONDITIONS DURING LATE NIGHT/MORNING. OVERALL, DIRECTIONS WILL
GENERALLY VARY FROM SE TO SW THROUGH THE PERIOD.
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...18
FIRE WEATHER...KUHLMAN/BENEDICT
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