841
FXUS65 KPSR 241001
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
301 AM MST MON AUG 24 2026
KEY MESSAGES
- EXTREME HEAT WARNINGS REMAIN IN EFFECT THROUGH SATURDAY WITH
DAILY MAJOR TO EXTREME HEATRISK.
- HIGH TEMPERATURES WILL REACH OR EXCEED 110 DEGREES NEARLY EVERY
DAY THIS WEEK, PEAKING RIGHT AROUND DAILY RECORDS TUESDAY
THROUGH THURSDAY.
- MONSOON STORM CHANCES FOR THE UPCOMING WORKWEEK WILL BE VERY
LIMITED WITH CHANCES BRIEFLY COMING TO AN END STARTING TUESDAY
BEFORE SLOWLY RETURNING BY NEXT WEEKEND.
SHORT TERM /TODAY THROUGH THURSDAY/
EARLY MORNING LINGERING SHOWERS AND A FEW THUNDERSTORMS WILL
GRADUALLY DIMINISH BY SUNRISE LEAVING A SOMEWHAT OVERTURNED
ATMOSPHERE AND SLIGHTLY COOLER TEMPERATURES ACROSS MUCH OF
SOUTHERN AND CENTRAL ARIZONA. THE SUBTROPICAL HIGH, WHICH IS
CURRENTLY CENTERED ALONG THE NEW MEXICO/TEXAS BORDER, IS SET TO
SHIFT WESTWARD TODAY INTO TUESDAY WITH THE CENTER REACHING
WESTERN NEW MEXICO ON TUESDAY. DRIER AIR IS ALREADY STARTING TO
MOVE IN FROM THE SOUTH AND THIS WILL CONTINUE THROUGH AT LEAST
TUESDAY, DROPPING LOW LEVEL MIXING RATIOS TO BETWEEN 6-8 G/KG.
THIS DRIER AIR IN COMBINATION WITH INCREASING SUBSIDENCE FROM THE
RIDGE WILL BASICALLY END RAIN CHANCES BEGINNING TUESDAY. FOR TODAY
HOWEVER, THERE SHOULD STILL BE ENOUGH LINGERING MOISTURE AND NOT
TOO HIGH OF CIN FOR A FEW ISOLATED SHOWERS OR WEAK STORMS ACROSS
HIGHER TERRAIN AREAS ACROSS ARIZONA AND SOUTHEAST CALIFORNIA. RAIN
CHANCES SHOULD THEN FALL TO BELOW 10% STARTING TUESDAY AND LIKELY
STAY THAT WAY THROUGH THURSDAY WITH THE RIDGE EVENTUALLY MOVING
DIRECTLY OVER SOUTHEAST ARIZONA AND SOUTHWEST NEW MEXICO.
THE MAIN FORECAST CONCERN FOR THE REST OF THE WEEK WILL BE THE
LATE AUGUST EXTREME HEAT. EXTREME HEAT WARNINGS REMAIN IN EFFECT
FOR THE MAJORITY OF THE AREA THROUGH SATURDAY WITH EXPECTATIONS OF
SOME EXPANSION OF THE WARNING INTO HIGHER TERRAIN LOCATIONS FOR
THE LATTER HALF OF THE WEEK. THE SLIGHTLY RAIN-COOLED AIR SHOULD
KEEP DAYTIME HIGHS TODAY MOSTLY IN A 106-110 DEGREE RANGE, BUT
THAT WILL QUICKLY CHANGE BEGINNING TUESDAY. THE DRYING CONDITIONS
AND INCREASING HEIGHTS FOR THE MIDDLE PART OF THE WEEK ARE
EXPECTED TO PUSH DAYTIME HIGHS WELL ABOVE 110 DEGREES. THE LATEST
NBM TEMPERATURES HAVE TRENDED DOWNWARD OVER THE PAST COUPLE OF
DAYS OF RUNS, BUT WITH THE NBM'S RECENT TRACK RECORD OF UNDER
DOING TEMPERATURES, WE HAVE BUMPED HIGHS UP A DEGREE OR TWO.
DAYTIME HIGHS ARE LIKELY TO REACH 112-116 DEGREES TUESDAY THROUGH
THURSDAY, POTENTIALLY TYING OR BREAKING A FEW DAILY RECORDS. VERY
WARM OVERNIGHT LOWS ARE ALSO FORECAST, EVENTUALLY LEADING TO
FAIRLY WIDESPREAD EXTREME HEATRISK BY WEDNESDAY.
LONG TERM /FRIDAY THROUGH SUNDAY/
ENSEMBLE GUIDANCE FAVORS SOME WEAKENING OF THE SUBTROPICAL HIGH
STARTING FRIDAY AS IT STARTS TO SHIFT BACK TO THE EAST. THIS SHIFT
ASSUMES A PACIFIC TROUGH MOVING INTO THE NORTHWESTERN U.S. LATE
WEEK. MODELS ALSO FAVOR SOME GRADUAL MOISTURE ADVECTION BY FRIDAY
AND LASTING THROUGH THE UPCOMING WEEKEND. GIVEN THE EXPECTED
INCREASE IN MOISTURE AND WEAKENING SUBSIDENCE, RAIN CHANCES SHOULD
RETURN AS EARLY AS FRIDAY BUT MORE LIKELY OVER THE WEEKEND.
NBM/WPC POPS SHOW 10-15% CHANCES OVER HIGH TERRAIN AREAS FRIDAY
AND SATURDAY BEFORE INCREASING AND EXPANDING INTO THE LOWER
DESERTS BY SUNDAY. THESE POPS MAY BE UNDERDONE SOMEWHAT
CONSIDERING WHAT THE LATEST MODELS RUNS SHOW, SO WE ANTICIPATE
HIGHER POPS SOON FROM THE NBM. TEMPERATURES SHOULD ALSO BEGIN TO
IMPROVE LATE WEEK AND THROUGH THE WEEKEND AS MOISTURE INCREASES
AND HEIGHTS GRADUALLY LOWER. THE LATEST FORECAST HIGHS STILL
MAINTAIN OR EVEN TOP 110 DEGREES THROUGH SATURDAY BEFORE DROPPING
TO BELOW 110 DEGREES BY SUNDAY OR MONDAY OF NEXT WEEK.
AVIATION
UPDATED AT 0550Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
GUSTY WINDS AND SHRA/TSRA ACTIVITY IN THE VICINITY DURING THE NEXT
COUPLE OF HOURS WILL BE THE MAIN AVIATION WEATHER CONCERN
THROUGHOUT THE TAF PERIOD. SHRA/TSRA ACTIVITY, WITH THE GREATEST
CONCENTRATION TO THE SOUTHWEST OF THE TERMINALS WILL CONTINUE
THROUGH 07Z, WITH VCSH LINGERING A BIT LONGER INTO THE OVERNIGHT
PERIOD. WIND DIRECTIONS THROUGH AT LEAST THE FIRST PART OF THE
OVERNIGHT WILL CONTINUE TO REMAIN ERRATIC DUE TO CONVECTIVE
ACTIVITY NEARBY BEFORE BECOMING LIGHT AND VARIABLE TO LIGHT
EASTERLY BY SUNRISE THROUGH EARLY MONDAY MORNING BEFORE SHIFTING
OUT OF THE WEST BY THE LATE MORNING HOURS. MUCH QUIETER CONDITIONS
ARE EXPECTED ON MONDAY WITH NO THREAT OF OUTFLOWS/THUNDERSTORMS.
SCT-BKN MID TO HIGH CLOUDS WILL CONTINUE THROUGH THE OVERNIGHT
PERIOD BEFORE COVERAGE DECREASES TO FEW-SCT DURING THE DAY MONDAY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS UNDER FEW-SCT MID/HIGH CLOUD DECKS CAN
BE EXPECTED THROUGHOUT THE TAF PERIOD. WINDS WILL GENERALLY BE OUT
OF THE SOUTHEAST AT KIPL AND WILL FLUCTUATE BETWEEN THE SOUTH-
SOUTHEAST TO SOUTHWEST AT KBLH. OVERALL WIND SPEEDS WILL RANGE
BETWEEN 8-15 KTS, HIGHEST AT KBLH.
FIRE WEATHER
HOT AND SEASONALLY DRY CONDITIONS WILL PREVAIL FOR MUCH IF NOT ALL
OF THE COMING WEEK. STRONG HIGH PRESSURE WILL SETTLE OVER THE
REGION BY MIDWEEK WITH GRADUAL DRYING CONDITIONS. MINIMUM RHS
TODAY WILL MOSTLY FALL BETWEEN 20-30%, BEFORE DROPPING BACK INTO
THE TEENS STARTING TUESDAY. TEMPERATURES WILL BE AROUND 5-10
DEGREES ABOVE NORMAL, WITH LOWER DESERT HIGHS ECLIPSING 110
DEGREES NEARLY EVERY AFTERNOON. EXPECT OVERALL LIGHT WINDS
FOLLOWING TYPICAL DIURNAL TENDENCIES WITH SOME MODEST AFTERNOON
UPSLOPE GUSTINESS.
CLIMATE
RECORD HIGHS:
DATE PHOENIX YUMA EL CENTRO
---- ------- ---- ---------
AUG 24 115 IN 2020 119 IN 1985 117 IN 1985
AUG 25 113 IN 2011 116 IN 1962 117 IN 1962
AUG 26 117 IN 2011 115 IN 2020 115 IN 1981
AUG 27 114 IN 2023 120 IN 1981 117 IN 1981
AUG 28 117 IN 2023 118 IN 2023 117 IN 2009
AUG 29 116 IN 2023 117 IN 1954 117 IN 2005
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST SATURDAY FOR AZZ530>555-559-
560.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT SATURDAY FOR CAZ562-565>567-
569-570.
SHORT TERM...KUHLMAN
LONG TERM...KUHLMAN
AVIATION...LOJERO
FIRE WEATHER...KUHLMAN
CLIMATE...18/KUHLMAN
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