554
FXUS65 KPSR 072126
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
226 PM MST FRI AUG 7 2026
KEY MESSAGES
- EXTREME HEAT WILL CONTINUE THROUGH THE WEEKEND, WITH AFTERNOON
HIGHS HOVERING NEAR TO SEVERAL DEGREES ABOVE NORMAL WHILE
HUMIDITY VALUES REMAIN HIGHER THAN NORMAL.
- SHOWER AND THUNDERSTORM ACTIVITY WILL BE MAINLY CONFINED TO
HIGHER TERRAIN AREAS OF SOUTHCENTRAL AZ THROUGH THIS WEEKEND
WITH GUSTY OUTFLOW WINDS AND BLOWING DUST THE MOST LIKELY
IMPACTS FOR THE LOWER DESERTS.
- MONSOON RAINFALL CHANCES BECOME MORE FAVORABLE AND WILL BEGIN TO
EXPAND INTO THE LOWER DESERTS BY LATE THIS WEEKEND AND INTO THE
START OF NEXT WEEK.
SHORT TERM /TODAY THROUGH SATURDAY/
LATEST VISIBLE SATELLITE IMAGERY INDICATES A GROWING CU FIELD
OVER THE MOGOLLON RIM AND WHITE MOUNTAINS AS WELL AS ACROSS
PORTIONS OF SOUTHEAST AZ. MESOANALYSIS INDICATES MLCAPE VALUES
INCREASING TO AROUND 1200-1500 J/KG OVER THE HIGHER TERRAIN OF
GILA COUNTY AND FAR E MARICOPA COUNTIES WHERE SKIES ARE CLEAR AND
SFC DEW POINTS ARE IN THE MID 50S TO LOWER 60S. HIGH-RES GUIDANCE
SUGGESTS STORMS CONTINUING TO DEVELOP OVER THE RIM AND PUSHING
INTO S GILA COUNTY BY EARLY THIS EVENING. WE WILL CONTINUE TO
MONITOR FOR A POTENTIAL OUTFLOW BOUNDARY THAT COULD SURGE INTO E
MARICOPA COUNTY, HOWEVER SUBSIDENCE ALOFT FROM A STRONG 596-598
DAM HIGH AND A STRONG CAPPING INVERSION (MLCIN -80 TO -100 J/KG)
WILL LIKELY LIMIT STORM ACTIVITY ACROSS THE LOWER DESERTS TONIGHT.
THEREFORE, POPS REMAIN ON THE ORDER OF 10-25% ACROSS MARICOPA AND
PINAL COUNTIES. IF ANY STORM DOES DEVELOP ALONG AN OUTFLOW
BOUNDARY, STRONG TO MARGINALLY SEVERE WIND GUSTS WILL BE POSSIBLE
WHICH COULD GENERATE AREAS OF BLOWING DUST. STORM CHANCES WILL
DIMINISH AFTER 06Z, LEADING TO A QUIET REST OF THE NIGHT. WITH THE
ADDITIONAL CLOUD COVER AND HIGHER DEW POINTS, OVERNIGHT LOWS WILL
REMAIN ABOVE NORMAL IN THE MID 80S TO AROUND 90 DEGREES.
EVEN THOUGH THE HIGH WILL REMAIN IN A FAVORABLE POSITION OVER THE 4-
CORNERS REGION FOR CONTINUED MONSOONAL ACTIVITY, HIGH PRESSURE ALOFT
WILL STRENGTHEN FURTHER ON SATURDAY. THIS WILL AGAIN PROVIDE A
STRONG SUBSIDENCE INVERSION OVER THE LOWER DESERTS. SLIGHTLY DRIER
AIR IS ALSO ANTICIPATED WITH SFC DEW POINTS FALLING INTO THE LOW TO
MID 50S. THESE CONDITIONS WILL LIKELY LIMIT STORM ACTIVITY ACROSS
THE LOWER DESERTS ASIDE FROM ANOTHER POTENTIAL OUTFLOW EMANATING
FROM CONVECTION OVER THE HIGH TERRAIN. NBM POPS DO APPEAR TO REFLECT
THIS SCENARIO AS RAIN CHANCES ARE VERY SIMILAR TO TODAY (10-20% FOR
THE LOWER DESERTS AND AROUND 30% OVER THE FOOTHILLS AND MOUNTAINS NE
OF PHOENIX).
THE UNSEASONABLY STRONG SUB-TROPICAL HIGH WILL CONTINUE TO REMAIN
ENTRENCHED OVER THE 4-CORNERS REGION THROUGH THIS WEEKEND WITH
500 MB HGHTS REMAINING AROUND 595-597 DAM THROUGH SUNDAY. HGHTS OF
THIS MAGNITUDE ARE IN THE 90TH-95TH PERCENTILE OF CLIMO FOR THIS
TIME OF YEAR. ALTHOUGH RECORD BREAKING TEMPERATURES ARE NOT
ANTICIPATED, AFTERNOON HIGHS WILL RUN A GOOD 4-8 DEGREES ABOVE
NORMAL FOR EARLY AUGUST, TRANSLATING TO READINGS RANGING NEAR
107-115 DEGREES. THESE TEMPERATURES WILL CONTINUE TO PROMOTE A
MODERATE TO MAJOR HEATRISK AND THUS AN EXTREME HEAT WARNING WILL
REMAIN IN EFFECT THROUGH THE REMAINDER OF THIS WEEKEND.
LONG TERM /SUNDAY THROUGH THURSDAY/
THE RELATIVE PAUSE IN CONVECTIVE ACTIVITY SHOULD BE FAIRLY SHORT
LIVED AS THE HIGH WILL EVENTUALLY BECOME PARKED OVER THE FOUR
CORNERS, INDUCING SOUTHEASTERLY FLOW OVER THE REGION WHICH SHOULD
PROVIDE RENEWED MOISTURE FLUX. POPS HAVE FALLEN SLIGHTLY COMPARED TO
24 HOURS AGO, MAINLY FOR LOWER ELEVATION AREAS, BUT THAT IS NOT MUCH
OF A SURPRISE AS IT MAKE TAKE A LITTLE BIT MORE TIME TO GET MOISTURE
PROFILES BACK TO MORE FAVORABLE LEVELS. THE MORE FAVORABLE SPOTS TO
SEE CONVECTION WILL ONCE AGAIN BE THE HIGH COUNTY AND SOUTHEAST
ARIZONA, BUT DOWNSTREAM EFFECTS FROM ANY ACTIVITY THAT DOES FORM
COULD HAVE IMPACTS ON OUR LOWER ELEVATION ZONES. ONCE WE GET
CLOSER, AND GET INSIDE THE HI-RES WINDOW, WE WILL HAVE A BETTER
IDEA ON WHAT IMPACTS TO EXPECT.
DAILY CHANCES FOR SHOWER AND THUNDERSTORMS WILL REACH INTO THE FRONT
HALF OF THE NEXT WORKWEEK AS SUFFICIENT MOISTURE STAYS IN PLACE. THE
LOWER DESERTS, IF NOT BY SUNDAY, MAY FINALLY GET IN ON SOME OF THE
ACTION AS LOW-LEVEL MOISTURE LOOKS TO IMPROVE WITH MODEL SOUNDINGS
INDICATING MIXING RATIOS REACHING 11-12 G/KG. THAT WILL AID IN
INCREASING INSTABILITY AND LIMITING THE CAP THAT HAS BEEN SO
PREVALENT THE PAST FEW DAYS. AS TYPICAL WITH THE MONSOON, HOW ONE
DAY PLAYS OUT WILL HEAVILY INFLUENCE WHAT HAPPENS THE SUBSEQUENT
DAY, SO DAY-TO-DAY FORECAST CHANGES SHOULD BE EXPECTED, BUT WITH
MOISTURE LEVELS NOT LIKELY TO FALL OFF THROUGH AT LEAST THE MIDDLE
PART OF THE WEEK, WE MAY BE LOOKING AT ONE OF THE MORE ACTIVE
PERIODS WE HAVE SEEN SO FAR THIS SUMMER.
TEMPERATURES WILL REMAIN SEVERAL DEGREES ABOVE SEASONAL LEVELS
THROUGH SUNDAY, BUT THERE APPEARS TO BE AT LEAST SOME RELIEF ON THE
HORIZON. WITH INCREASED MOISTURE, STORM COVERAGE, AND CLOUD COVER,
AFTERNOON HIGHS OVER SOUTH-CENTRAL ARIZONA ARE EXPECTED TO FALL MUCH
CLOSER TO NORMAL FOR THIS TIME OF YEAR WITH PROJECTED LOWER-DESERT
HIGHS BETWEEN 101-106 DEGREES BY TUESDAY. AREAS FURTHER DISPLACED
FROM THE STORM ACTIVITY, NAMELY SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA, WILL SEE TEMPERATURES GRADUALLY DECREASE TOO THANKS TO A
WEAKENING TREND WITH THE PREVAILING HIGH, BUT READINGS SHOULD REMAIN
SLIGHTLY HIGHER RELATIVE TO LOCATIONS FURTHER EAST. HIGHS FOR THOSE
WESTERN DESERT LOCATIONS WILL BE CLOSER TO 105-110 DEGREES THROUGH
AT LEAST THURSDAY.
AVIATION
UPDATED AT 1840Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
OUTFLOW WINDS, BLDU, REDUCED VIS, AND A VERY SLIM CHANCE FOR
THUNDERSTORM ACTIVITY THIS EVENING WILL BE THE MAIN AVIATION
WEATHER CHALLENGES DURING THE UPCOMING TAF PERIOD. IN THE
MEANTIME, CONDITIONS WILL REMAIN RELATIVELY TRANQUIL THROUGH THIS
AFTERNOON WITH WESTERLY WINDS THIS AFTERNOON AND EVENING. SOME
OCCASIONAL AFTERNOON GUSTS IN THE MID TO UPPER TEENS WILL BE
POSSIBLE. HEADING INTO THIS EVENING, THUNDERSTORM ACTIVITY ACROSS
THE HIGHER TERRAIN TO THE NORTH AND EAST MAY APPROACH THE PHOENIX
METRO. CONFIDENCE IS INCREASING THAT THESE THUNDERSTORMS WILL NOT
BE STRONG ENOUGH/BE CLUSTERED TOGETHER ENOUGH TO SEND A STRONG
ENOUGH OUTFLOW INTO THE PHOENIX METRO AND ANY OUTFLOW FROM THESE
STORMS IS EXPECTED TO WASHOUT PRIOR TO REACHING THE METRO.
HOWEVER, CONFIDENCE IS NOW INCREASING THAT THERE WILL BE A STRONG
ENOUGH COMPLEX OF STORMS IN SE AZ TO SEND AN OUTFLOW UP INTO THE
PHOENIX METRO. DESPITE CONFIDENCE INCREASING IN AN OUTFLOW FROM
THE S/SE, CONFIDENCE REMAINS LOW ON IF IT WILL REACH THE METRO AND
IF IT DOES HOW STRONG WILL IT BE AND IF IT WILL BE CARRYING BLDU
AND THE ASSOCIATED REDUCED VIS. THIS OUTFLOW LOOKS TO ARRIVE IN
THE PHOENIX METRO BETWEEN 05-06Z. CONFIDENCE IS HIGH ENOUGH THAT I
HAVE INTRODUCED A TEMPO GROUP, FROM 05-06Z, OF 6SM VIS AND HZ AT
KIWA, BUT HAVE LEFT IT OUT OF THE OTHER TAFS. IF THIS OUTFLOW IS
STRONG ENOUGH WE COULD SEE ANOTHER REPEAT EVENT FROM MONDAY AND
WEDNESDAY, WHICH COULD ALSO MEAN LINGERING DUST AND REDUCED VIS
INTO TOMORROW MORNING/AFTERNOON WITH SLANTWISE VISIBILITY ISSUES.
BEHIND THIS OUTFLOW WINDS ARE EXPECTED TO RETURN TO THEIR TYPICAL
DIURNAL PATTERNS WITH A SE'RLY WIND DEVELOPING DURING THE
OVERNIGHT/EARLY MORNING HOURS ON SATURDAY AND THE TYPICAL WESTERLY
SHIFT BY LATE TOMORROW MORNING/EARLY TOMORROW AFTERNOON. WINDS ARE
EXPECTED TO GO LIGHT AND VARIABLE DURING THE OVERNIGHT/EARLY
MORNING HOURS AT KSDL AND KDVT. FEW HIGH CLOUDS ARE EXPECTED THIS
AFTERNOON WITH COVERAGE INCREASING TO SCT-BKN AGAIN THIS EVENING.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS UNDER FEW TO OCCASIONALLY SCT MID TO
HIGH-LEVEL CLOUD DECKS CAN BE EXPECTED THROUGHOUT THE TAF PERIOD.
AT KIPL, SOUTHEASTERLY WINDS WILL PREVAIL THROUGH THIS AFTERNOON
WITH A WESTERLY SHIFT LIKELY THIS EVENING AND THEN BACK
SOUTHEASTERLY EARLY TOMORROW MORNING. AT KBLH, WINDS WILL
GENERALLY FLUCTUATE OUT OF THE SOUTH TO SOUTHWEST. OVERALL SPEEDS
WILL REMAIN AOB 10 KTS.
FIRE WEATHER
HOT TEMPERATURES WITH ELEVATED HUMIDITY LEVELS WILL CONTINUE THROUGH
THE WEEKEND. ALTHOUGH HUMIDITY LEVELS WILL TREND DOWN, REGIONAL
READINGS SHOULD REMAIN AT 15% OR ABOVE THROUGH SATURDAY, AND
INCREASE BACK TO AROUND 20% OR GREATER ON SUNDAY. OVERNIGHT RECOVERY
WILL OFFER MODEST TO DECENT RELIEF AS MAXRHS RANGE GENERALLY BETWEEN
30-55% THROUGH SUNDAY, WITH EVEN BETTER READINGS EXPECTED BY EARLY
NEXT WEEK. RAIN CHANCES THROUGH SATURDAY WILL BE MOSTLY CONFINED TO
HIGH TERRAIN AREAS AND SOUTHEASTERN ARIZONA, WITH LOWER DESERT
CHANCES REMAINING 15% OR BELOW. BY SUNDAY, INCREASING MOISTURE WILL
RESULT IN AN UPTREND IN LOWER ELEVATION SHOWER AND THUNDERSTORM
CHANCES, WHICH APPEARS LIKELY TO PERSIST INTO THE FOLLOWING WEEK.
OUTSIDE OF THUNDERSTORM OUTFLOWS, WINDS WILL FOLLOW FAMILIAR DIURNAL
TRENDS, WITH TYPICAL AFTERNOON UPSLOPE BREEZINESS AROUND 20 MPH.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST SUNDAY FOR AZZ530>544-546-
548>551-553>555-559.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT SUNDAY FOR CAZ560>570.
SHORT TERM...SALERNO
LONG TERM...RW
AVIATION...BERISLAVICH
FIRE WEATHER...RW/SALERNO
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