937
FXUS65 KPSR 281833
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1133 AM MST MON JUL 28 2025
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- WIDESPREAD MODERATE HEATRISK WITH LOWER DESERT HIGH TEMPERATURES
AROUND 110 DEGREES WILL BE COMMON EACH DAY THIS WEEK.
- A RETURN TO A MORE TYPICAL MONSOON PATTERN WILL ALLOW SHOWER AND
THUNDERSTORM ACTIVITY TO INCREASE FOR EASTERN PORTIONS OF
ARIZONA TODAY INTO TUESDAY AND THEN INTO SOUTH-CENTRAL ARIZONA
WEDNESDAY INTO THURSDAY.
SHORT TERM /TODAY THROUGH TUESDAY/
TODAY INTO TUESDAY WILL BE A TRANSITION PERIOD FOR MUCH OF THE
REGION AS THE UPPER LEVEL TROUGH TO OUR NORTHWEST SHIFTS FARTHER
AWAY WHILE THE SUBTROPICAL RIDGE CURRENTLY CENTERED OVER THE
LOWER MS RIVER VALLEY CONTINUES TO NUDGE BACK INTO OUR REGION. THE
DRY AIR MASS WHICH HAS BEEN PRESENT OVER OUR REGION SINCE THE
MIDDLE OF LAST WEEK WILL ALSO BEGIN TO MODIFY. THIS WILL BE AIDED
BY A WEAK INVERTED TROUGH WHICH IS NOW MOVING INTO SONORA AND IS
FORECAST TO REACH FAR SOUTHEAST ARIZONA LATER TODAY INTO TONIGHT.
MOISTURE WILL IMPROVE MODESTLY ACROSS SOUTHEAST ARIZONA TO AS FAR
NORTH AS THE WHITE MTNS BY THIS AFTERNOON PROVIDING FOR SOME
SCATTERED SHOWERS AND A FEW THUNDERSTORMS. AS THE INVERTED TROUGH
MOVES INTO SOUTHEAST ARIZONA BY TONIGHT, SOUTHEASTERLY FLOW INTO
THE AREA WILL CONTINUE TO BRING BETTER MOISTURE INTO TUESDAY.
SHOWER AND STORM COVERAGE ON TUESDAY MAY BE SLIGHTLY BETTER THAN
TODAY, BUT OVERALL IT IS EXPECTED TO BE CONFINED TO HIGHER TERRAIN
AREAS OF EASTERN ARIZONA.
TEMPERATURES TODAY AND TUESDAY ARE FORECAST TO HEAT UP EVEN MORE
WITH THE LOWER DESERTS SEEING HIGHS BETWEEN 108-112 DEGREES (3-6
DEGREES ABOVE NORMAL), BUT OVERNIGHT LOWS ARE STILL EXPECTED TO
MOSTLY FALL WITHIN THE NORMAL RANGE.
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
THE INVERTED TROUGH SLOWLY PROGRESSING INTO FAR SOUTH-CENTRAL
ARIZONA ON WEDNESDAY WITH WEAK MOISTURE ADVECTING INTO THE AREA.
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 DCAPES WILL BE QUITE HIGH AT AROUND 1500
J/KG. THIS SHOULD AT LEAST POSE A VERY LOCALIZED THREAT FOR
STRONG WINDS ACROSS THE AREA.
THE INVERTED TROUGH IS LIKELY TO WASH OUT OVER SOUTH-CENTRAL
ARIZONA BY THURSDAY, BUT MOISTURE SHOULD CONTINUE TO INCREASE AND
REACH ITS PEAK DURING THE DAYTIME HOURS 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 MUCAPES
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 POSSIBLY EXTENDING INTO THE LOWER
DESERTS BY WEDNESDAY. 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 5-10% TODAY,
BEFORE INCREASING INTO THE TEENS BY WEDNESDAY. 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. MOISTURE AND RAIN CHANCES ARE THEN LIKELY TO SPREAD
WESTWARD INTO SOUTH-CENTRAL ARIZONA BY WEDNESDAY OR AT THE LATEST
ON THURSDAY WITH A MODEST INCREASE IN HUMIDITIES.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...KUHLMAN
LONG TERM...KUHLMAN
AVIATION...WHITTOCK/BERISLAVICH
FIRE WEATHER...KUHLMAN
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