215
FXUS65 KPSR 222329
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
429 PM MST SAT AUG 22 2026
UPDATE...UPDATED 00Z AVIATION DISCUSSION
KEY MESSAGES
- HIGH TEMPERATURES REACH OR EXCEED 110 DEGREES NEARLY EVERY DAY
THROUGH THE NEXT WEEK AND WILL BE NEAR DAILY RECORDS, WHILE
MORNING LOWS REMAIN UNUSUALLY WARM.
- EXTREME HEAT WARNINGS ARE IN EFFECT THROUGH NEXT SATURDAY
EVENING WITH DAILY MAJOR TO EXTREME HEATRISK.
- AFTERNOON AND EVENING STRONG TO LOCALLY SEVERE THUNDERSTORMS
WILL PRIMARILY FAVOR HIGHER TERRAIN AREAS THROUGH THE START OF
NEXT WEEK, WITH DRIER AND LESS FAVORABLE CONDITIONS NEXT WEEK.
SHORT TERM /TODAY THROUGH MONDAY/
EXTREME HEAT WILL BE THE PRIMARY WEATHER HAZARD THROUGH THE SHORT
AND LONG TERM FORECAST WITH VERY STRONG HIGH PRESSURE PERSISTING
OVER THE REGION. LATEST OBJECTIVE ANALYSIS STILL SHOWS A 599DAM
ANTICYCLONE CENTERED OVER NORTHERN NM, WITH H5 HEIGHTS AROUND
595-597DAM OVER THE LOCAL AREA. THESE MAGNITUDES ARE AT OR ABOVE
THE 99TH PERCENTILE OF CLIMATOLOGY. THIS WILL CONTINUE LEADING TO
WELL ABOVE NORMAL HIGH AND LOW TEMPERATURES THROUGH THIS WEEKEND.
A DRYING AND WARMING OF THE PBL WAS OBSERVED OVER THE LAST 24
HOURS, AS SEEN IN OBSERVED SOUNDINGS. THIS SHOULD RESULT IN HIGH
TEMPERATURES THIS AFTERNOON 1-3 DEGREES WARMER THAN YESTERDAY,
WITH LOWER DESERTS TOPPING OUT AROUND 112-116 DEGREES. A SLIGHT
WEAKENING OF THE SUBTROPICAL HIGH, AND REPOSITIONING TO EASTERN
NM, SUNDAY INTO MONDAY WILL SUPPORT A SLIGHT COOLING OF
TEMPERATURES THROUGH MONDAY. POTENTIALLY MORE ACTIVE SHOWERS AND
STORMS SUNDAY EVENING/NIGHT IN SOUTH-CENTRAL AZ MAY ADD A BIT TO
THE COOLING INTO MONDAY. LATEST NBM FORECAST HIGHS FOR SUNDAY ARE
AROUND 108-114 DEGREES AND THEN 106-112 DEGREES FOR MONDAY.
MORNING LOW TEMPERATURES WILL REMAIN VERY WARM, UP TO 5-10 DEGREES
ABOVE NORMAL, IN THE MID 80S TO AROUND 90 DEGREES ACROSS THE LOWER
DESERTS. THE UNUSUALLY HOT TEMPERATURES WILL LEAD TO WIDESPREAD
MAJOR HEATRISK TODAY AND SUNDAY, WITH A DECREASE IN COVERAGE OF
MAJOR HEATRISK FOR MONDAY. AN EXTREME HEAT WARNING REMAINS IN
EFFECT THROUGH THIS WEEKEND.
AFTERNOON THUNDERSTORMS TODAY SHOULD MOSTLY FAVOR THE SAME AREAS
AS YESTERDAY, BUT WITH THE DRYING OF THE PBL, SURFACE-BASED
INSTABILITY WILL BE LOWER TODAY. MEAN MIXING RATIOS ARE DOWN 8
G/KG OR LOWER AND SURFACE DEW POINTS AT MIDDAY WERE MOSTLY AROUND
50-55 DEGREES. LOWER INSTABILITY MEANS OVERALL LESS INTENSE
UPDRAFT STRENGTH. THIS DOES NOT MEAN STORMS THAT DEVELOP CANNOT
STILL BECOME STRONG TO SEVERE. WITH THE HIGH T-TD SPREADS AND HIGH
LCLS, DCAPE REMAINS QUITE HIGH (>1500 J/KG), WHICH WILL PROMOTE
STRONG TO LOCALLY SEVERE DOWNBURSTS. LATEST HI-RES MODELS FAVOR
ISOLATED STORMS DEVELOPING MOSTLY ALONG THE MOUNTAINS EAST OF
PHOENIX AND OVER TERRAIN FEATURES SOUTH OF PHOENIX, WITH A FOCUS
MOSTLY IN CENTRAL PIMA COUNTY AND PORTIONS OF SOUTHERN MARICOPA
AND WESTERN PINAL COUNTIES. THE STORMS TO THE SOUTH WILL BE
CAPABLE OF SENDING DUSTY OUTFLOWS NORTHWARD HEADING INTO THE
EVENING, ALONG WITH DEBRIS CLOUDS AND PERHAPS SOME WEAK SHOWERS OR
VIRGA. JUST LIKE YESTERDAY, THE ODDS OF AN OUTFLOW POPPING OFF
STORMS CLOSER TO OR IN PHOENIX ARE LOW (5-10%), BUT IT IS STILL
NOT IMPOSSIBLE FOR 1-2 STRONG TO SEVERE STORMS TO POP UP WITH THE
RIGHT AMOUNT OF FORCING. SOME ACCAS SHOWERS ALSO CANNOT BE RULED
OUT ACROSS SOUTH-CENTRAL AZ HEADING INTO SUNDAY MORNING WITHIN
SOME OF THE DEBRIS CLOUDS MOVING ACROSS THE AREA.
FOR SUNDAY, MODELS CONTINUE TO SUPPORT A STRONG MOISTURE RETURN,
ALBEIT BRIEF, IN THE EVENING AND OVERNIGHT HOURS. THERE ARE
INDICATIONS THAT INSTABILITY WILL INCREASE AGAIN SOUTH AND
SOUTHWEST OF PHOENIX WITH STORMS AGAIN DEVELOPING IN SIMILAR
LOCATIONS WITH SIMILAR POTENTIAL FOR STRONG TO LOCALLY SEVERE WIND
GUSTS. THEN HEADING INTO THE EVENING AND OVERNIGHT HOURS IT LOOKS
LIKE THERE WILL BE A STRONG GULF SURGE AS WELL AS INDICATIONS OF
PERHAPS A SUBTLE SHORTWAVE/VORT MAX MOVING UP OUT OF SONORA. THIS
MAY INCREASE STORM SURVIVABILITY INTO THE PHOENIX AREA. NBM POPS
REMAIN QUITE LOW DESPITE THIS. THE 12Z HREF SHOWS A 30%
NEIGHBORHOOD PROBABILITY FOR DBZ>40 IN SOUTH-CENTRAL AZ, INCLUDING
PHOENIX, SUNDAY EVENING/NIGHT. SO, POPS WERE INCREASED SLIGHTLY
TO AT LEAST SHOW A SLIGHT CHANCE (10-20%) ACROSS SOUTH-CENTRAL AZ.
ISOLATED STORMS ARE AGAIN FORECAST OVER HIGHER TERRAIN FEATURES
FOR MONDAY AFTERNOON AND EVENING, BUT THERE MAY BE STRONGER STORMS
AND GREATER COVERAGE OVER SOME OF THE FEATURES WEST OF PHOENIX,
LIKE THE KOFAS TO HARCUVAR MTNS AND PORTIONS OF EASTERN RIVERSIDE
COUNTY FOLLOWING THE MOISTURE INCREASE THE NIGHT BEFORE.
LONG TERM /TUESDAY THROUGH NEXT FRIDAY/
ENSEMBLE MEMBERS ARE IN GOOD AGREEMENT THAT BY TUESDAY DRIER AIR
WILL START TO FILTER BACK INTO THE REGION AS THE SUBTROPICAL HIGH
RESTRENGTHENS AND STARTS TO RETROGRADE WESTWARD BACK TO OVER OUR
REGION. BY THE MIDDLE OF THE WEEK THE CENTER OF THE HIGH WILL BE
STRADDLING THE AZ/NM BORDER AND BY THE END OF THE WEEK THE CENTER
OF THE HIGH IS FORECAST TO BE OVER AZ. AS THE HIGH MOVES
OVERHEAD, PWATS ARE SHOWN TO DROP INTO A 0.9-1.2" RANGE ACROSS
OUR REGION AND WITH WARMER TEMPERATURES ALOFT AND SUBSIDENCE
CHANCES FOR THUNDERSTORMS WILL BE POOR ACROSS THE REGION. THE NBM
SHOWS THAT TUESDAY AND WEDNESDAY THERE COULD BE ENOUGH MOISTURE
AROUND TO SUPPORT ISOLATED THUNDERSTORM CHANCES FOR THE HIGHER
TERRAIN AREAS. BUT BY THE END OF NEXT WEEK THUNDERSTORM CHANCES
FOR OUR AREA SHUT OFF AND WILL MAINLY BE RELEGATED TO THE MOGOLLON
RIM.
UNUSUALLY HOT TEMPERATURES WILL BE THE MAIN STORY NEXT WEEK. AS
MENTIONED ABOVE THE SUBTROPICAL HIGH WILL SLOWLY RETROGRADE BACK
OVER OUR REGION BEGINNING ON TUESDAY, WHICH WILL RESULT IN A QUICK
WARMING TREND FOR OUR AREA. THE HIGH IS ALSO EXPECTED TO
STRENGTHEN TO AROUND 596-598DAM DURING THIS TIME. THE COMBINATION
OF THE CENTER SETTLING OVER OUR REGION AND STRENGTHENING WILL
RESULT IN TEMPERATURES HEATING UP TO AROUND 10 DEGREES ABOVE
NORMAL FOR THIS TIME OF YEAR. AFTERNOON HIGHS (MORNING LOWS) ARE
FORECASTED TO BE IN THE 112-118 (85-93) DEGREE RANGE ACROSS THE
LOWER DESERTS AND IN THE 102-112 (75-85) DEGREE RANGE ACROSS THE
HIGHER TERRAIN AREAS. THERE IS A GOOD CHANCE DAILY RECORD HIGHS
AND WARM LOWS WILL BE TIED OR BROKEN AND TEMPERATURES MAY EVEN
NEAR MONTHLY RECORDS. THE INCREASE IN TEMPERATURES WILL ALSO
RESULT IN AN INCREASE IN COVERAGE OF MAJOR HEATRISK, BACK TO
WIDESPREAD BEGINNING TUESDAY AND THEN WIDESPREAD EXTREME HEATRISK
BY THURSDAY. CONFIDENCE IN THE HEAT FORECAST FOR NEXT WEEK REMAINS
HIGH. SO, THE EXTREME HEAT WARNING WILL CONTINUE THROUGH THE
WORKWEEK AND HAS NOW BEEN EXTENDED THROUGH SATURDAY, IN
COLLABORATION WITH THE TUCSON OFFICE. THE WARNING WILL LIKELY BE
EXPANDED TO OUR ENTIRE CWA BY THE MIDDLE OF THE WEEK WITH THE
DEVELOPMENT OF WIDESPREAD EXTREME HEATRISK.
AVIATION
UPDATED AT 2325Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE POTENTIAL FOR A GUSTY OUTFLOW THIS EVENING CONTINUES TO BE THE
MAIN AVIATION WEATHER CHALLENGE THROUGH SUNDAY AFTERNOON. LIGHT
WESTERLY WINDS WILL PERSIST THROUGH THE EARLY EVENING HOURS BEFORE
THE POTENTIAL FOR AN OUTFLOW TO IMPACT THE TERMINALS AFTER
02-03Z. IF AN OUTFLOW WERE TO IMPACT THE AREA, IT WILL MOST LIKELY
COME FROM THE SOUTH. ALONG WITH SOME GUSTY WINDS, THERE WILL ALSO
BE THE POTENTIAL FOR SOME BLDU ISSUES AS WELL, ESPECIALLY AT KIWA
AND KPHX. OTHERWISE, CONDITIONS SHOULD BECOME MORE TRANQUIL AFTER
04-05Z, WITH EASTERLY WINDS LIKELY DURING THE OVERNIGHT AND EARLY
MORNING BEFORE THE WESTERLY SHIFT LATE MORNING/EARLY AFTERNOON.
FEW-SCT MID/HIGH CLOUD DECKS WILL BE COMMON THROUGHOUT THE PERIOD,
ALTHOUGH A PERIOD OF BKN COVERAGE WILL BE POSSIBLE, ESPECIALLY
THIS EVENING.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR WEATHER ISSUES UNDER FEW-SCT MID/HIGH CLOUD DECKS CAN BE
EXPECTED THROUGHOUT THE TAF PERIOD. TRENDS IN THE OVERALL WIND
DIRECTION SHOULD BE SIMILAR TO THE LAST 24 HOURS, WITH WESTERLY
WINDS THIS EVENING AND OVERNIGHT TURNING OUT OF THE SOUTHEAST
EARLY SUNDAY MORNING AT KIPL AND WINDS FLUCTUATING BETWEEN THE
SOUTH-SOUTHEAST AND SOUTHWEST AT KBLH. OVERALL SPEEDS WILL
GENERALLY REMAIN UNDER 12 KTS WITH SOME MODEST AFTERNOON/EARLY
EVENING GUSTS.
FIRE WEATHER
HOT AND SEASONALLY DRY CONDITIONS ARE EXPECTED NEARLY EVERY DAY,
THROUGH NEXT WEEK. ASIDE FROM A BRIEF INCREASE IN MOISTURE SUNDAY-
MONDAY, MINIMUM RH VALUES EACH AFTERNOON WILL BE AROUND 12-18% (15-
25% SUN-MON). TEMPERATURES WILL BE AROUND 5-10 DEGREES ABOVE NORMAL
THROUGH THE NEXT WEEK, WITH LOWER DESERT HIGHS ECLIPSING 110 DEGREES
NEARLY EVERY AFTERNOON. THERE WILL BE SLIGHT CHANCES FOR STORMS
EACH AFTERNOON THROUGH MONDAY, BUT THEY WILL MOSTLY FAVOR THE
HIGHER TERRAIN AREAS. DRIER CONDITIONS, WITH LOWER STORM CHANCES
ARE EXPECTED BY THE MIDDLE OF NEXT WEEK. OUTSIDE OF THUNDERSTORM
OUTFLOW WINDS, WINDS WILL FOLLOW THE TYPICAL DIURNAL TENDENCIES
WITH SOME MODEST AFTERNOON UPSLOPE GUSTINESS.
CLIMATE
RECORD HIGHS:
DATE PHOENIX YUMA EL CENTRO
---- ------- ---- ---------
AUG 22 113 IN 2011 115 IN 1969 117 IN 1969
AUG 23 114 IN 2011 115 IN 2011 116 IN 1969
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
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...BENEDICT
LONG TERM...BERISLAVICH/BENEDICT
AVIATION...LOJERO
FIRE WEATHER...BERISLAVICH/BENEDICT
CLIMATE...18
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