293
FXUS65 KPSR 160611
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1111 PM MST WED JUL 15 2026
UPDATE
UPDATED 06Z AVIATION DISCUSSION.
KEY MESSAGES
- HOT AND MUGGY CONDITIONS WILL CONTINUE TODAY, HOWEVER
TEMPERATURES WILL COOL INTO A NEAR TO BELOW NORMAL RANGE BY THE
END OF THE WEEK.
- SHOWER AND THUNDERSTORMS CHANCES WILL INCREASE TODAY ACROSS
EASTERN AND CENTRAL ARIZONA WITH GUSTY WINDS AND LOCALLY HEAVY
RAINFALL POSSIBLE.
- THUNDERSTORMS MAY BECOME MORE WIDESPREAD THURSDAY AND FRIDAY
WITH THE POTENTIAL FOR HEAVY RAINFALL AND FLASH FLOODING.
SHORT TERM /TODAY THROUGH FRIDAY/
EXPANSIVE RIDGING ALOFT COVERS MUCH OF THE CONUS THIS AFTERNOON
UNDER A QUASI-REX BLOCK PATTERN FEATURING A DISTINCT EASTERLY
CUTOFF LOW OVER CENTRAL TEXAS BOUNDED BY HIGH PRESSURE ARCING FROM
THE MID- ATLANTIC TO THE NORTHERN PLAINS, THEN INTO THE
SOUTHWEST. THIS PLACES THE FORECAST AREA UNDER DEEP EASTERLY FLOW
SUBJECT TO SHORTWAVE ENERGY PASSING FROM THE AFOREMENTIONED TEXAS
CUTOFF TOWARDS THE SOUTHERN PERIPHERY OF THE HIGH PRESSURE RIDGE
SITUATED OVER ARIZONA. THIS GENERAL PATTERN IS TYPICAL FOR
MID/LATE JULY, ALBEIT MORE AMPLIFIED WITH STRONGER ANOMALY CENTERS
THAN IS TYPICAL, RESULTING IN MORE IMPRESSIVE FORCING MECHANISMS
AROUND THE REGION. MEANWHILE, THIS SYNOPTIC PATTERN HAS ALLOWED
AMPLE MOISTURE TO STREAM INTO MUCH OF THE CWA WITH BOUNDARY LAYER
MIXING RATIOS IN A FAVORABLE 10-12 G/KG RANGE WHILE TOTAL COLUMN
PWATS EXCEED 1.50" SETTING THE STAGE FOR HEAVY RAINFALL POTENTIAL
WITH ANY SLOW MOVING OR TRAINING THUNDERSTORMS.
WITH THE LOCAL ENVIRONMENT RECOVERING FROM CONVECTION SUNDAY AND
MONDAY, THE FORECAST AREA IS SITUATED IN A FAIRLY FAVORABLE
LOCATION FOR SUSTAINED THUNDERSTORMS WITH MODEST STRETCHING AND
DIVERGENCE AT JET LEVEL BETWEEN WELL DEFINED EASTERLY
WAVES/CUTOFFS OVER TEXAS AND WESTERN MEXICO AND A SW JET OVER THE
GREAT BASIN. FORECAST BUFR SOUNDINGS FOR THIS AFTERNOON/EVENING
SUGGEST MLCAPE 500-750 J/KG MATERIALIZING AFTER DAYTIME HEATING
AND COINCIDENT WITH MINIMAL CINH. WHILE THE MOISTENING OF THE
BOUNDARY LAYER HAS REDUCED DCAPE SOMEWHAT, VALUES IN EXCESS OF
1200 J/KG STILL APPEAR PROBABLE INDICATING ROBUST OUTFLOWS LIKELY
PRODUCING VERY GUSTY WINDS (ALBEIT LARGELY SUB-SEVERE), BLOWING
DUST, AND SUFFICIENT LIFT CAPABLE OF INITIATING NEW STORMS. THE
MINIMAL INHIBITION MAY ALLOW NEW STORMS TO FORM ALONG A SINGLE
OUTFLOW, HOWEVER COLLIDING OUTFLOWS WILL BE MORE BENEFICIAL, AND
THE PREPONDERANCE OF MODEL OUTPUT INDICATES THESE COLLISIONS
FOCUSED OVER WESTERN MARICOPA COUNTY THIS EVENING. FORWARD STORM
MOTION AND INFLUENCE FROM RAPIDLY PROPAGATING OUTFLOWS SHOULD
RESTRICT THE FLASH FLOOD THREAT THIS EVENING, THOUGH CONGEALING
STORMS COULD PRODUCE A LOCALIZED THREAT.
THE SYNOPTIC PATTERN WILL BECOME EVEN MORE CONDUCIVE FOR ROBUST
THUNDERSTORMS THURSDAY AS AT LEAST ONE SHORTWAVE SHED FROM THE
AFOREMENTIONED TEXAS CUTOFF PROGRESSES TOWARDS SOUTH-CENTRAL
ARIZONA DURING PEAK HEATING. WITH CONVECTIVE DEBRIS AND OUTFLOWS
PUMPING ADDITIONAL MOISTURE INTO THE MIDDLE AND LOWER TROPOSPHERE,
TOTAL COLUMN PWATS 1.75-2.00" SHOULD BE COMMON WHILE BOUNDARY
LAYER MIXING RATIOS SETTLE AROUND 12-13 G/KG BY THURSDAY
AFTERNOON. THIS MOISTURE PROFILE SHOULD RESULT IN A NEAR EQUAL
MLCAPE/DCAPE BALANCE IN A "SWEET SPOT" OF 1000-1500 J/KG
HISTORICALLY PRESENT DURING BIG MONSOON THUNDERSTORM EVENTS.
CONVECTIVE INHIBITION SHOULD BE NEARLY ABSENT LATE AFTERNOON/EARLY
EVENING, AND WITH UNDERLYING DEEP LAYER ASCENT, IT SHOULD ONLY
TAKE WEAK OUTFLOWS TO INITIATE ADDITIONAL STORMS. INTERSECTING
OUTFLOW BOUNDARIES ARE ALSO LIKELY WITH CONSOLIDATING STORMS OVER
PARTS OF THE CWA RESULTING IN HEAVY RAINFALL AND FLASH FLOODING.
RAINFALL RATES AT LEAST 2-3"/HR APPEAR LIKELY GIVEN THE MOISTURE
PROFILES, AND A FLASH FLOOD WATCH HAS BEEN ISSUED FOR SOUTH-
CENTRAL ARIZONA COUNTIES. AT THIS POINT, HREF AND GLOBAL MODEL
OUTPUT SUGGESTS NORTHERN PINAL AND SW MARICOPA COUNTIES AS THE
FOCUS FOR THE HEAVIEST RAINFALL.
CONSIDERABLE FORECAST UNCERTAINTY EXISTS FRIDAY CONTINGENT UPON
THE STRENGTH AND EXPANSE OF THUNDERSTORMS THURSDAY NIGHT. A LARGE
SUBSET OF MODELING INDICATES THE ATMOSPHERE BECOMING COMPLETELY
OVERTURNED BY STORMS AND OUTFLOWS FRIDAY MORNING WITH FORECAST
SOUNDINGS DEPICTING A CLASSIC, POST-EVENT MOIST ADIABATIC PROFILE.
SHOULD THIS COME TO FRUITION (BETTER THAN A 50% CHANCE),
CONVECTIVE POTENTIAL THE REMAINDER OF FRIDAY WOULD BECOME MINIMAL,
AT BEST, GIVEN THE COMBINED EXTENSIVE CLOUD COVER AND POOR LAPSE
RATES RESULTING IN ESSENTIALLY NO INSTABILITY. A SLIGHT
ALTERNATIVE OUTCOME IS HINTED AT BY RECENT OPERATIONAL ECMWF AND
NAMNEST OUTPUT WHICH SUGGESTS A WELL DEFINED MCV JUXTAPOSED WITH A
POOL OF HIGHER THETA-E ADVECTING NORTH THROUGH THE PHOENIX METRO
FRIDAY MORNING. WHILE THESE TYPE MODEL FORECASTS WITH MORNING
STORMS FORCED BY AN MCV AND COPIOUS DEEP MOISTURE ARE COMMON
DURING THE MONSOON, THEY ONLY COME TO FRUITION OCCASIONALLY EVERY
SUMMER, BUT WHEN THIS SCENARIO UNFOLDS, VERY EFFICIENT RAIN RATES
AND FLOODING ENSUES. REGARDLESS, THE STRONGEST MODEL EVIDENCE
INDICATES ONLY SMALL POCKETS OF INSTABILITY REMAINING FRIDAY
AFTERNOON, AND HAVE CUT MANDATED NBM POPS SUBSTANTIALLY AS EVEN
THE MOST AGGRESSIVE MODELING THAT ALWAYS FORECASTS STORMS HAS
LITTLE CONVECTIVE RESPONSE FRIDAY AFTERNOON/EVENING.
LONG TERM /SATURDAY THROUGH TUESDAY/
MODERATE FORECAST UNCERTAINTY IS STILL AN ISSUE FOR THIS WEEKEND
INTO NEXT WEEK AS DAY-TO-DAY SHOWER AND THUNDERSTORM CHANCES ARE
LIKELY TO PERSIST. SOME SLIGHT DRYING OVER THE WEEKEND, AS THE
EASTERLY WAVE TO OUR EAST SOUTHEAST GRADUALLY WEAKENS, IS LIKELY
TO BRING LOWER RAIN CHANCES COMPARED TO THURSDAY AND FRIDAY, BUT
THAT DOES NOT MEAN IT WILL NOT BE ACTIVE IN SOME AREAS. AS OF
RIGHT NOW, GUIDANCE IS FAVORING THE ARIZONA HIGH TERRAIN THIS
WEEKEND WITH DAILY POPS OF 50-70%. AN EASTERLY STEERING FLOW IS
ALSO LIKELY TO PERSIST WHICH WILL ENABLE AT LEAST SOME CHANCES
(20-30%) OF SHOWERS AND STORMS INTO THE LOWER DESERTS THIS
WEEKEND. LINGERING ASCENT ALSO LOOKS POSSIBLE THIS WEEKEND FROM
THE EASTERLY WAVE, ALTHOUGH THIS IS MORE LIKELY TO BENEFIT FAR
SOUTHEAST ARIZONA AND NORTHERN MEXICO.
MODEL UNCERTAINTY INCREASES FURTHER DURING THE FIRST HALF OF NEXT
WEEK AS GUIDANCE IS SHIFTING WHERE THE SUBTROPICAL HIGH CENTER
MAY BE AND WHETHER OR NOT ANOTHER EASTERLY WAVE WILL IMPACT OUR
REGION. THERE SEEMS TO AT LEAST BE SOME AGREEMENT IN GRADUALLY
SHIFTING THE HIGH CENTER SOUTHWESTWARD TO SOMEWHERE OVER THE
CENTRAL ROCKIES OR CENTRAL PLAINS SUNDAY INTO MONDAY, BUT WHERE IT
GOES THEREAFTER IS MUCH MORE UNCERTAIN. THE GEFS FAVORS THE HIGH
CENTER SETTLING ANYWHERE FROM THE FOUR CORNERS AREA TO INTO
CENTRAL NEW MEXICO, WHILE THE EPS SHOWS IT MORE OVER NEW MEXICO
INTO WESTERN TEXAS. THE FIRST HALF OF NEXT WEEK IS STILL LIKELY TO
BE FAIRLY ACTIVE AS FAR AS STORM POTENTIAL, AND COULD EVEN BE
VERY ACTIVE IF THE EASTERLY WAVE BECOMES A BIG FACTOR. HOWEVER,
THE LATTER HALF OF NEXT WEEK MAY INVOLVE A DECREASE IN MONSOON
ACTIVITY IF THE HIGH CENTER TRULY MOVES CLOSER TO OR INTO ARIZONA.
NBM TEMPERATURE TRENDS SHOW BELOW NORMAL TEMPERATURES LASTING
THROUGH THE WEEKEND FOR MUCH OF ARIZONA AND LIKELY PERSISTING BUT
GRADUALLY WARMING THROUGH THE FIRST HALF OF NEXT WEEK. LOCATIONS
ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA SHOULD SEE
TEMPERATURES RIGHT AROUND NORMAL WITH MOST DAYS SEEING LITTLE
MONSOON CONVECTION.
AVIATION
UPDATED AT 0611Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
A POTENTIAL EXTENDED PERIOD OF ERRATIC WINDS AND VCTS/TSRA IMPACTS
THURSDAY EVENING THROUGH THURSDAY NIGHT WILL BE THE PRIMARY
AVIATION IMPACT AND FORECAST CHALLENGE. AHEAD OF THAT TIME PERIOD,
THERE IS LOW POTENTIAL (10%) FOR SOME HIGH-BASED SHOWERS AND MAYBE
A STORM TO DEVELOP EARLY THURSDAY MORNING. TOO LOW FOR INCLUSION
IN THE TAFS. STORMS THURSDAY AFTERNOON ARE FORECAST TO FOCUS
INITIALLY TO THE NORTH AND THEN TO THE SOUTH AND SOUTHEAST, WHICH
MAY LEAD TO PROMINENT OUTFLOWS FROM BOTH DIRECTIONS, WITH A
NORTHERLY OUTFLOW FAVORED FIRST IN THE LATE AFTERNOON. THERE ARE
GOOD CHANCES (40-60%) FOR VCTS/TSRA & VCSH/SHRA AT TERMINALS
HEADING INTO THE LATE EVENING AND OVERNIGHT HOURS THURSDAY. SOME
STORMS MAY PRODUCE VERY HEAVY, BLINDING, RAINFALL. CLOUD BASES
WILL MOSTLY STAY AT OR ABOVE 8-10K FT AGL, BUT THERE IS POTENTIAL
FOR LOWER CLOUD BASES, DOWN TO 6-7K FT AGL. THE DUST POTENTIAL
THURSDAY IS LOW.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED DURING THE NEXT 24 HOURS.
SE WINDS WILL BE COMMON AT KIPL, THOUGH A BRIEF SWITCH OF THE W/SW
MAY DEVELOP THURSDAY EVENING. S/SW'RLY WINDS WILL PREVAIL AT KBLH.
A BRIEF WINDOW OF GUSTS AROUND 20-25 KT OVERNIGHT MAY DEVELOP AT
BOTH TERMINALS AND AGAIN THURSDAY AFTERNOON. INCREASING MID-LEVEL
CLOUDS TONIGHT INTO THURSDAY MORNING IS EXPECTED. THERE IS LOW
POTENTIAL (10-20%) FOR AN ISOLATED SHOWER OR STORM THURSDAY
MORNING AND IN THE AFTERNOON AND EVENING, CONDITIONAL ON THE
EVOLUTION OF DISTURBANCES TO THE EAST OF THE AREA.
FIRE WEATHER
ACTIVE MONSOON WEATHER WITH ELEVATED MOISTURE LEVELS WILL CONTINUE
THROUGH THE REST OF THE WEEK. SHOWER AND THUNDERSTORM CHANCES WILL
INCREASE OVER THE EASTERN DISTRICTS TODAY THROUGH THURSDAY WITH ONLY
ISOLATED CHANCES OVER THE WESTERN DISTRICTS. HEAVY RAINFALL WILL
ALSO BE POSSIBLE ACROSS THE EASTERN DISTRICTS BY THURSDAY AFTERNOON.
MINRHS WILL IMPROVE FROM EAST TO WEST OVER THE NEXT FEW DAYS,
INCREASING FROM 20-35% TODAY TO 30-50% BY FRIDAY. OUTSIDE OF
POTENTIAL THUNDERSTORM OUTFLOWS, WINDS FOR THE EASTERN DISTRICTS
WILL TEND TO BE LIGHT AND SOMEWHAT FAVOR DIURNAL TRENDS.
WINDS WILL PREDOMINATELY FAVOR THE SOUTH WHILE BECOMING BREEZY
STARTING THURSDAY ACROSS THE WESTERN DISTRICTS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST THURSDAY FOR AZZ530-532.
FLOOD WATCH FROM THURSDAY AFTERNOON THROUGH LATE THURSDAY NIGHT
FOR AZZ534-537>563.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT THURSDAY FOR CAZ562-563-
565>567-569-570.
SHORT TERM...18
LONG TERM...KUHLMAN
AVIATION...BENEDICT
FIRE WEATHER...KUHLMAN
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