544
FXUS65 KPSR 050537
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1037 PM MST WED JUN 4 2025
UPDATE
UPDATED 06Z AVIATION DISCUSSION.
KEY MESSAGES
- SCATTERED SHOWERS AND STORMS ARE EXPECTED OVER NORTHERN ARIZONA
THROUGH THE REST OF THE DAY, WITH ISOLATED ACTIVITY OVER THE
SOUTH CENTRAL ARIZONA HIGH TERRAIN OVER THE NEXT FEW HOURS.
- CONDITIONS RETURN TO SEASONABLY HOT AND DRY BY THE END OF THE
WORKWEEK AND THROUGH THE WEEKEND.
- AREAS OF MODERATE HEATRISK DEVELOP BY SATURDAY AND BECOME MORE
WIDESPREAD BY SUNDAY.
DISCUSSION
CURRENT UPPER LEVEL OBJECTIVE ANALYSIS PLACES THE CENTER OF A LOW
OVER CENTRAL AZ. AS THE UPPER LOW CONTINUES TO EJECT
NORTHEASTWARD, A MIDLEVEL SUBSIDENCE INVERSION IS SHOWN DEVELOPING
OVER MUCH OF THE EASTERN CWA, PRECLUDING THE DEVELOPMENT OF ANY
ROBUST SHOWER/STORM ACTIVITY OVER SOUTH-CENTRAL AZ, HOWEVER, THIS
MIDLEVEL INVERSION IS MUCH LESS PRONOUNCED IN GFS BUFR SOUNDINGS
FOR POINTS IN THE WESTERN CWA. AS SUCH, SOME DEEPER UPDRAFTS COULD
POTENTIALLY FORM FURTHER WEST, THOUGH MIDLEVEL LAPSE RATES ARE
STILL QUITE LOW, CAPE IS SKINNY, AND LCLS ARE HIGH. LATEST RUNS OF
SOME CAMS FEATURE ISOLATED CONVECTIVE SHOWERS FORMING OVER THE
KOFA, CHOCOLATE, AND WESTERN JTNP MOUNTAINS, CONSISTENT WITH
CURRENT CUMULUS BUILDUPS SEEN IN VISIBLE SATELLITE IMAGERY.
MEANWHILE, SOME LINGERING SHOWERS HAVE BEEN PASSING OVER PORTIONS
OF SOUTHERN GILA COUNTY SINCE LATE THIS MORNING, AND THIS ACTIVITY
HAS ALREADY LESSENED CONSIDERABLY. ALL CONVECTIVE ACTIVITY OVER
THE FORECAST AREA SHOULD CEASE BEFORE SUNSET. OVERALL, EXPECT
LITTLE TO NO ADDITIONAL RAINFALL FROM ANY CONVECTIVE SHOWERS
THROUGH THE REMAINDER OF THE AFTERNOON, THOUGH A FEW STRIKES OF
LIGHTNING CANNOT BE RULED OUT.
FOR THE REMAINDER OF THE WORKWEEK, ENSEMBLES SHOW SOME LEVEL OF
POSITIVELY-TILTED BROAD TROUGHING WILL EXIST OVER THE WESTERN US,
BUT A SUBTROPICAL RIDGE WILL START TO EDGE CLOSER FROM THE
SOUTHEAST, BRINGING POSITIVE MIDLEVEL HEIGHT ANOMALIES OVERHEAD.
AS A RESULT, EXPECT THERMAL PROFILES TO WARM THROUGH THE END OF
THE WORKWEEK, WITH A RETURN TO TRIPLE DIGIT HIGHS FOR THE
TYPICALLY HOTTER LOCALES ON THURSDAY (65% CHANCE FOR 100+ DEG F
AT PHOENIX SKY HARBOR BY THURSDAY, AND 98% CHANCE BY FRIDAY.)
BY THE WEEKEND, ENSEMBLES SHOW THE FORECAST AREA SOLIDLY UNDER THE
INFLUENCE OF THE AFOREMENTIONED SUBTROPICAL RIDGE, WITH ANOTHER
UPPER LEVEL EAST PACIFIC RIDGE POSITIONING ITSELF OFF THE PACIFIC
NORTHWEST COAST. IN BETWEEN THESE FEATURES, A CUTOFF LOW IS
PINCHED OFF THE BASE OF THE BROAD WESTERN US TROUGHING AND
RETROGRADES WEST OF CALIFORNIA (ALMOST DIRECTLY SOUTH OF THE EAST
PACIFIC RIDGE.) WITH THE SUBTROPICAL RIDGE OVERHEAD, EXPECT H5
HEIGHTS TO PEAK AROUND 590 DAM. THE LATEST NBM ADVERTISES LOWER
DESERT HIGHS PEAKING AROUND 105-109 ON SUNDAY-MONDAY, WITH A
10-20% PROBABILITIES OF REACHING 110F AT SKY HARBOR AND AROUND
30% PROBABILITIES FOR THAT OVER PORTIONS OF SOUTHEAST CA. WITH
THESE FORECAST HIGHS, MODERATE HEATRISK WILL DEVELOP OVER THE
REGION THIS WEEKEND, BUT IT SEEMS TEMPERATURES WILL NOT REACH
EXTREME HEAT LEVELS. GUIDANCE THEN MOSTLY FAVORS THE CUTOFF LOW
MOVING FROM JUST OFF THE CALIFORNIA COAST OVER THE WEEKEND INTO
OR NEAR OUR REGION BY AROUND NEXT TUESDAY. THIS FEATURE IS NOT
LIKELY TO BRING MUCH CHANGE FOR OUR REGION AS IT LOOKS QUITE DRY,
BUT IT MAY BE ENOUGH TO DROP DAYTIME HIGHS BACK INTO THE NORMAL
RANGE BY THE MIDDLE OF NEXT WEEK.
AVIATION
UPDATED AT 0536Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:
LIGHT DIURNAL WIND TENDENCIES AND MOSTLY CLEAR SKIES WILL PREVAIL
THROUGH THURSDAY. WIND SPEEDS WILL MOSTLY REMAIN <10 KTS WITH
EXTENDED PERIODS OF LIGHT VARIABILITY, ESPECIALLY TONIGHT THROUGH
THURSDAY MORNING.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO SIGNIFICANT AVIATION CONCERNS THROUGH THE TAF PERIOD WITH
MOSTLY CLEAR SKIES PREVAILING. WINDS AT KIPL WILL FAVOR S-E
DIRECTIONS AND S DIRECTIONS AT KBLH. WIND SPEEDS AT BOTH TERMINALS
WILL REMAIN MOSTLY AT OR BELOW 10 KTS. THERE WILL BE A SURGE OF
SOUTHERLY WINDS THURSDAY EVENING, BEGINNING AROUND 00-02Z AT BOTH
TERMINALS, THAT WILL BE CAPABLE OF PUSHING SPEEDS TO 10-15 KTS
WITH GUSTS INTO THE UPPER TEENS FOR A FEW HOURS.
FIRE WEATHER
A WEATHER SYSTEM WILL EXIT THE REGION LATER TODAY WITH LINGERING
CHANCES FOR SHOWERS AND ISOLATED THUNDERSTORMS INTO THE AFTERNOON
ACROSS THE ARIZONA HIGHER TERRAIN. DRYING CONDITIONS AND HOTTER
TEMPERATURES ARE THEN EXPECTED THROUGH THE REST OF THE WEEK.
MINRHS WILL REMAIN ELEVATED TODAY AT MOSTLY ABOVE 20-25% BEFORE
LOWING TO 10-15% BY FRIDAY. WINDS SHOULD FOLLOW FAIRLY TYPICAL
DIURNAL TENDENCIES WITH PERIODIC AFTERNOON UPSLOPE GUSTINESS.
THE DRY WEATHER PATTERN IS EXPECTED TO CONTINUE THROUGH THE
WEEKEND INTO EARLY NEXT WEEK WITH TEMPERATURES RUNNING 5-10
DEGREES ABOVE NORMAL AND DAILY MINRHS MOSTLY IN A 5-10% RANGE.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
DISCUSSION...WHITTOCK
AVIATION...BENEDICT
FIRE WEATHER...WHITTOCK/KUHLMAN
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