742
FXUS65 KPSR 071002
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
302 AM MST TUE JUL 7 2026
KEY MESSAGES
- VERY HOT TEMPERATURES ARE EXPECTED THROUGH THIS WEEK, RESULTING
IN WIDESPREAD MODERATE HEAT RISK AND AREAS OF MAJOR HEAT RISK
THROUGH AT LEAST THURSDAY.
- DUE TO THE EXPECTED MAJOR HEAT RISK, AN EXTREME HEAT WARNING HAS
BEEN POSTED FOR THE LOWER DESERTS OF SOUTH-CENTRAL AND SOUTHWEST
ARIZONA, AND SOUTHEAST CALIFORNIA, THROUGH THURSDAY.
- OUTSIDE OF AN ISOLATED CHANCE OF A SHOWER OR THUNDERSTORM OVER
HIGHER TERRAIN AREAS OF EASTERN ARIZONA, DRY CONDITIONS WILL
PREVAIL FOR THE MAJORITY OF OUR FORECAST AREA THROUGH FRIDAY.
SHORT TERM /TODAY THROUGH THURSDAY/
THE MAIN FORECAST CONCERN OVER THE NEXT FEW DAYS WILL BE THE
BUILDING HEAT CREATING AREAS OF MAJOR HEATRISK. EXTREME HEAT
WARNINGS GO INTO EFFECT LATER THIS MORNING FOR THE BULK OF THE
AREA AND LAST THROUGH THURSDAY. A FAIRLY STRONG SUBTROPICAL RIDGE
IS CURRENTLY SHIFTING WESTWARD THROUGH THE REGION WITH H5 HEIGHTS
OF 592-594DM. THE RIDGE IS FORECAST TO STRENGTHEN INTO TONIGHT
REACHING H5 HEIGHTS OF 594-596DM, BEFORE THE RIDGE CENTER SHIFTS
WEST OF THE AREA ON WEDNESDAY. THE BUILDING HEIGHTS AND WARMING
ALOFT WILL ALLOW FOR DAYTIME HIGHS REACHING BETWEEN 110-114
DEGREES TODAY BEFORE PEAKING WEDNESDAY AND/OR THURSDAY BETWEEN
111-116 DEGREES. LOW LEVEL MOISTURE HAS ALSO INCREASED ENOUGH TO
CURTAIL EFFICIENT NOCTURNAL COOLING RESULTING IN VERY WARM
OVERNIGHT TEMPERATURES OVER THE NEXT FEW DAYS. EXPECT LOWS MOSTLY
IN THE 80S FOR RURAL LOWER DESERT LOCATIONS TO AS WARM AS THE LOW
90S IN CENTRAL PHOENIX.
ALTHOUGH LOW LEVEL MOISTURE HAS INCREASED WITH SURFACE DEW POINTS
ANYWHERE FROM THE MID 40S TO THE MID 50S, MOISTURE WITHIN THE
REST OF THE BOUNDARY LAYER REMAINS ON THE LOWER SIDE. SUBSIDENCE
UNDER THE RIDGE WILL BE A LIMITING FACTOR FOR POTENTIAL CONVECTION
OVER THE NEXT FEW DAYS, BUT IT WON'T STOP IT FROM DEVELOPING OVER
THE EASTERN ARIZONA HIGH TERRAIN. HI-RES CAMS SHOW SCATTERED
SHOWERS AND STORMS DEVELOPING BOTH THIS AFTERNOON AND WEDNESDAY
AFTERNOON, BUT LIMITED CAPE AND VERY WEAK STEERING FLOW SHOULD
KEEP ANY STORMS ON THE WEAKER SIDE AND SHORT-LIVED. HOWEVER,
STRONG GUSTY WINDS OF 30-40 MPH SHOULD BE POSSIBLE UNDER ANY
THUNDERSTORMS THAT DEVELOP. GUIDANCE ALSO IS NOW SUGGESTING A
WESTWARD PROPAGATING OUTFLOW MAY REACH EASTERN PORTIONS OF THE
PHOENIX AREA THIS EVENING AND MAYBE AGAIN WEDNESDAY EVENING. THIS
OUTFLOW IS NOT EXPECTED TO BE ENOUGH TO SPARK OFF ANY CONVECTION
WITHIN THE LOWER DESERTS AND WIND GUSTS SHOULD MOSTLY STAY UNDER
30 MPH. GUIDANCE IS STILL FAVORING A DECREASE IN CONVECTIVE
POTENTIAL BY THURSDAY DUE TO THE RIDGE SHIFTING TO OUR WEST AND
SLIGHT DRYING OCCURRING OVER THE REGION. SUBSIDENCE IS ALSO
EXPECTED TO INCREASE LATE WEEK WHICH SHOULD FURTHER LIMIT ANY HIGH
TERRAIN CONVECTIVE POTENTIAL.
LONG TERM /FRIDAY THROUGH MONDAY/
ABOVE NORMAL TEMPERATURES WITH AT LEAST HIGH-END MODERATE HEATRISK
IS FORECAST FOR FRIDAY, BEFORE SOME GRADUAL COOLING AND THEN
EVENTUALLY A BIG UPTICK ON MONSOON STORM ACTIVITY IS LIKELY OVER
THE WEEKEND INTO EARLY NEXT WEEK. FORECAST HIGHS FRIDAY ARE STILL
RANGING FROM 110-114 DEGREES ACROSS THE WESTERN LOWER DESERTS,
WHILE LOWERING HEIGHTS FOR CENTRAL AND EASTERN ARIZONA SHOULD
ALLOW FOR HIGHS TO LOWER TO 108-112 DEGREES. LOW LEVEL MOISTURE IS
ALSO SHOWN TO START INCREASING AGAIN AS EARLY AS FRIDAY WITH
MOISTURE STREAMING OFF THE GULF OF CALIFORNIA. HOWEVER, DRIER AIR
ALOFT WILL DILUTE SOME OF THIS LOW LEVEL MOISTURE INCREASE AND
IT'S LIKELY TO TAKE A COUPLE DAYS FOR MOISTURE AND INSTABILITY TO
INCREASE ENOUGH FOR STORM POTENTIAL TO RAMP BACK UP. SHOWER AND
STORM CHANCES ARE CURRENTLY EXPECTED TO PICK UP ON SATURDAY ACROSS
AT LEAST SOUTHEAST ARIZONA WITH SOME POTENTIAL FOR DECAYING
ACTIVITY INTO THE SOUTH-CENTRAL ARIZONA LOWER DESERTS SATURDAY
EVENING/NIGHT.
STARTING SUNDAY OR NEXT MONDAY, MODELS ARE REALLY SETTING UP THE
REGION TO BECOME QUITE ACTIVE AS THERE IS GOOD AGREEMENT SHIFTING
THE HIGH CENTER SOMEWHERE TO OUR NORTHEAST. GUIDANCE IS FAVORING A
VERY LARGE RIDGE WITH RECORD OR NEAR RECORD H5 HEIGHTS SETTING UP
OVER THE NORTHERN PLAINS BY SUNDAY. THE RIDGE IS EXPECTED TO BE
VERY EXPANSIVE STRETCHING AS FAR WEST AS THE FOUR CORNERS AREA AND
AS FAR EAST AS THE OHIO RIVER VALLEY. AS OF RIGHT NOW, THE LARGE
SCALE FLOW IS LIKELY TO BECOME BLOCKED WITH THIS RIDGE LASTING
THROUGH MOST, IF NOT ALL OF NEXT WEEK.
THE EXPECTED LARGE EXPANSE AND STRENGTH OF THIS RIDGE SHOULD BE
QUITE BENEFICIAL FOR INCREASING MOISTURE AND STORM CHANCES OVER
MUCH OF THE DESERT SOUTHWEST NEXT WEEK. ALTHOUGH UNCERTAINTY
REMAINS, ESPECIALLY WITH HOW MUCH MOISTURE AND WITH ANY POTENTIAL
DISTURBANCES THAT ARE LIKELY TO MOVE OVER OR NEAR OUR REGION, WE
ARE ANTICIPATING OUR FIRST DECENT PERIOD OF MONSOON ACTIVITY NEXT
WEEK. IT IS TOO EARLY TO SPECULATE ON WHICH DAYS WILL BE THE MOST
ACTIVE, BUT NBM/WPC POPS FOR SUNDAY ARE ALREADY AS HIGH AS 30-40%
OVER EASTERN AND SOUTH-CENTRAL ARIZONA. ONCE THE MONSOON ACTIVITY
KICKS INTO GEAR, TEMPERATURES SHOULD ALSO BEGIN TO DIP CLOSER TO
SEASONAL NORMALS.
AVIATION
UPDATED AT 0900Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
AN EASTERLY OUTFLOW PRODUCING SOME MINOR GUSTY WINDS EARLY THIS
EVENING WILL BE THE MAIN AVIATION WEATHER ISSUE THROUGHOUT THE TAF
PERIOD. IN THE MEANTIME, EASTERLY WINDS EARLY THIS EVENING WILL
TRANSITION OUT OF THE WEST BY THE MID/LATER MORNING WITH SOME
OCCASIONAL AFTERNOON GUSTS INTO THE MID TO UPPER TEENS. ISOLATED TO
WIDELY SCATTERED STORMS OVER THE HIGHER TERRAIN EAST OF PHOENIX IS
LIKELY TO SEND AN EASTERLY OUTFLOW INTO THE AREA TERMINALS EARLY
THIS EVENING, WITH PEAK GUSTS UPWARDS OF 20 KTS. MOSTLY CLEAR SKIES
WITH THE EXCEPTION OF A FEW MID TO HIGH LEVEL CLOUDS CAN BE EXPECTED
THROUGHOUT THE PERIOD.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
SOME MINOR GUSTY WINDS, ESPECIALLY AT KBLH, WILL BE THE MAIN
AVIATION WEATHER ISSUE THROUGHOUT THE TAF PERIOD UNDER CLEAR SKIES.
AT KIPL, SOUTHEAST WINDS WILL PREVAIL THROUGH THIS AFTERNOON BEFORE
SHIFTING OUT OF THE WEST FOR A PERIOD EARLY THIS EVENING. AT KBLH,
WINDS WILL GENERALLY FLUCTUATE BETWEEN THE SOUTH-SOUTHEAST TO
SOUTHWEST. OVERALL SUSTAINED SPEEDS WILL REMAIN AOB 12 KTS, WITH
SOME OCCASIONAL AFTERNOON GUSTS NEAR 20 KTS AT KBLH.
FIRE WEATHER
GUSTY AND ERRATIC THUNDERSTORM WINDS AND ISOLATED DRY LIGHTNING
OVER THE FAR EASTERN DISTRICTS THE NEXT FEW AFTERNOONS WILL BE
THE MAIN FIRE WEATHER CONCERNS. OUTSIDE OF ANY POTENTIAL
OUTFLOWS, WINDS SHOULD FAVOR LIGHT AND DIURNAL TRENDS WITH TYPICAL
AFTERNOON BREEZINESS AROUND 20 MPH. AFTERNOON RH VALUES BETWEEN
10-15% WILL BE COMMON ACROSS THE REGION. OVERNIGHT RECOVERIES
WILL OFFER ONLY LIMITED TO MODEST RELIEF AS MAXRH VALUES RANGE
GENERALLY BETWEEN 20-45%. TEMPERATURES ARE EXPECTED TO RUN WELL
ABOVE NORMAL THROUGH THE MIDDLE OF THE WEEK, WITH THE LOWEST
ELEVATIONS REACHING BETWEEN 110-115 DEGREES. A DECREASE IN MONSOON
ACTIVITY IS LIKELY LATE WEEK, BEFORE PICKING UP AGAIN AND BECOMING
MORE WIDESPREAD BY EARLY NEXT WEEK. MOISTURE LEVELS AND HUMIDITIES
SHOULD ALSO IMPROVE CONSIDERABLY BY EARLY NEXT WEEK, ALLEVIATING
MUCH OF THE FIRE WEATHER CONCERNS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM MST
THURSDAY FOR AZZ530>534-536>551-553>555-559-560-562.
CA...EXTREME HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM PDT
THURSDAY FOR CAZ562-564>570.
SHORT TERM...KUHLMAN
LONG TERM...KUHLMAN
AVIATION...LOJERO
FIRE WEATHER...KUHLMAN
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