056
FXUS65 KPSR 220909
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
209 AM MST SAT AUG 22 2026
KEY MESSAGES
- HIGH TEMPERATURES REACH OR EXCEED 110 DEGREES NEARLY EVERY DAY
THROUGH THE NEXT WEEK AND WILL BE WITHIN A FEW DEGREES OF DAILY
RECORDS, WHILE MORNING LOWS REMAIN UNUSUALLY WARM.
- EXTREME HEAT WARNINGS ARE IN EFFECT THROUGH FRIDAY EVENING WITH
DAILY MAJOR TO EXTREME HEATRISK.
- THUNDERSTORMS WILL PRIMARILY FAVOR HIGHER TERRAIN AREAS THROUGH
EARLY 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. EARLY MORNING OBJECTIVE ANALYSIS
SHOWS A 596DM HIGH PRESSURE CENTERED OVER CO/NM. MODELS SHOW THAT
THIS HIGH WILL SLOWLY PROGRESS EASTWARD THROUGH THE BEGINNING OF
NEXT WEEK. DESPITE THE CENTER OF THE HIGH MOVING AWAY FROM OUR
REGION, H5 HEIGHTS OVER OUR REGION WILL REMAIN IN A 594-597DM
RANGE. WITH HEIGHTS OF THIS MAGNITUDE, THE NBM CONTINUES TO SHOW
AFTERNOON HIGHS (MORNING LOWS) OF 110-116 (83-91) DEGREES ACROSS
THE LOWER DESERTS AND 100-110 (70-80) DEGREES ACROSS THE HIGHER
TERRAIN AREAS. TEMPERATURES OF THIS MAGNITUDE ARE 5-8 DEGREES
ABOVE DAILY NORMALS AND SOME LOCATIONS COULD TIE OR BREAK THEIR
DAILY RECORDS (SEE CLIMATE SECTION BELOW). THESE TEMPERATURES WILL
LEAD TO WIDESPREAD HIGH-END MODERATE TO MAJOR HEAT RISK ACROSS
MUCH OF THE CWA AND THEREFOR THE EXTREME HEAT WARNING REMAINS IN
EFFECT.
THE BEST THUNDERSTORM CHANCES WILL EXIST ACROSS THE HIGHER TERRAIN
AREAS THROUGH THE BEGINNING OF NEXT WEEK WITH ONLY SLIGHT CHANCES
FOR SOME ISOLATED ACTIVITY ACROSS THE LOWER DESERTS. THUNDERSTORM
CHANCES ACROSS THE LOWER DESERTS FOR THIS AFTERNOON ARE AROUND
10-20%. WHILE SOME HI-RES MODELS (HRRR AND RRFS) ARE TRYING TO
PICK UP ON SOME MORE SCATTERED ACTIVITY ACROSS SOUTH- CENTRAL AZ
(INCLUDING THE PHOENIX METRO) THEY ARE LIKELY OVERDOING THE
COVERAGE. MODELS SHOW LIMITED MOISTURE TODAY (PWATS OF 1.0-1.3"),
MIXING RATIOS ONLY AROUND 6-7 G/KG, MUCAPE VALUES LESS THEN 500
J/KG, AND AROUND 25-50 J/KG OF CIN. THE HI- RES MODELS SHOWING
SCATTERED TO WIDESPREAD ACTIVITY FOR THIS EVENING ARE LIKELY
PICKING UP ON SOME UPPER-LEVEL DIVERGENCE AND COLLIDING OUTFLOWS.
WHILE THERE WILL LIKELY BE MULTIPLE OUTFLOWS MOVING OFF THE HIGHER
TERRAIN THIS EVENING NOT MUCH ACTIVITY (OTHER THAN SOME ISOLATED
SHOWERS AND MAYBE A FEW ISOLATED STORMS) IS EXPECTED EVEN IF THEY
DO COLLIDE DUE TO ALL THE LIMITING FACTORS MENTIONED EARLIER.
STRONG TO LOCALLY SEVERE WIND GUSTS AND AREAS OF BLOWING DUST WILL
BE THE PRIMARY HAZARD WITH ANY STORM THIS AFTERNOON AND EVENING,
WITH HIGH DCAPE VALUES (1800-2000 J/KG).
MODELS ARE IN DECENT AGREEMENT THAT THERE WILL BE A SLIGHT
INCREASE IN MOISTURE ON SUNDAY AND MONDAY (PWATS INCREASE TO
AROUND 1.1-1.6" ACROSS THE AREA) WITH THE HIGHEST MOISTURE
EXPECTEDON MONDAY. INSTABILITY WILL BE ABOUT THE SAME ON SUNDAY
AS TODAY, BUT WILL INCREASE TO AROUND 1000-1500 J/KG ON MONDAY.
ADDITIONALLY, MIXING RATIONS WILL INCREASE TO AROUND 10 G/KG ON
MONDAY. DESPITE THE INCREASE IN MOISTURE, INSTABILITY, AND MIXING
RATIOS MODELS SHOW AN INCREASE IN CIN (100-200 J/KG). ACTIVITY
EACH DAY WILL DEPEND ON HOW THE DAY PRIOR PLAYS OUT. BUT RIGHT
NOW, MONDAY LOOKS TO HAVE SLIGHTLY BETTER CHANCES THAN SUNDAY.
EITHER WAY, MOST OF THE LOWER DESERTS ARE EXPECTED TO REMAIN DRY
WITH THE BEST CHANCES (AND COVERAGE) OF THUNDERSTORMS EXPECTED
ACROSS THE HIGHER TERRAIN AREAS TO THE EAST OF THE PHOENIX METRO.
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
STARTS TO RETROGRADE BACK 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 WILL BE OVER AZ.
AS THE HIGH MOVES OVERHEAD, PWATS WILL DROP INTO A 0.8-1.2" RANGE
ACROSS OUR REGION AND STEERING FLOW WILL BE OUT OF THE S/SW. THE
COMBINATION OF THESE FACTORS WILL LEAD TO POOR CHANCES FOR
THUNDERSTORM DEVELOPMENT 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
GRADUAL 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 110-116 (85-95) DEGREE RANGE ACROSS THE
LOWER DESERTS AND IN THE 100-110 (75-85) DEGREE RANGE ACROSS THE
HIGHER TERRAIN AREAS. THE INCREASE IN TEMPERATURES WILL ALSO
RESULT IN AN INCREASE IN HEATRISK, WITH WIDESPREAD EXTREME
HEATRISK FORECAST FOR THE MAJORITY OF THE CWA BY WEDNESDAY. THERE
REMAINS HIGH CONFIDENCE IN THE HEAT FORECAST FOR NEXT WEEK. SO,
THE EXTREME HEAT WARNING REMAINS IN EFFECT THROUGH NEXT FRIDAY AND
WILL LIKELY NEED TO BE EXPANDED TO MORE AREAS BY THE MIDDLE OF
THE WEEK AND MAY EVENTUALLY NEED TO BE EXTENDED INTO NEXT WEEKEND.
AVIATION
UPDATED AT 0515Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR AVIATION CONCERNS ARE EXPECTED THROUGH EARLY SATURDAY
AFTERNOON UNDER SCT TO SOMETIMES BKN CLOUD DECKS. WINDS WILL
FOLLOW FAMILIAR DIURNAL TRENDS WITH PERIODS OF VRB CONDITIONS
DURING THE OVERNIGHT HOURS. FORECAST CONFIDENCE DECREASES FOR LATE
SATURDAY AFTERNOON INTO THE EVENING TIMEFRAME. THERE IS A SIGNAL
THAT VCSH/VCTS WILL INITIATE AS EARLY AS 23Z, THOUGH RAIN CHANCES
ARE ONLY AROUND 20% AT THIS TIME. TO REFLECT CONVECTIVE
UNCERTAINTY, PROB30 GROUPS HAVE BEEN ADDED TO EACH METRO
TERMINAL. IF STORMS DO DEVELOP, THEY COULD PROVIDE MULTIPLE
OUTFLOWS, RESULTING IN GUSTY AND ERRATIC WINDS, AND DEPENDING ON
WHERE THE OUTFLOW ORIGINATE, BLDU COULD ALSO BECOME A OPERATIONAL
FACTOR. CHANGES IN SUBSEQUENT TAF UPDATES SHOULD BE ANTICIPATED.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED THROUGH THE FRONT HALF OF
THE TAF PERIOD. WINDS WILL FAVOR A WESTERLY COMPONENT AT KIPL,
WHILE VRB CONDITIONS WILL BE COMMON AT KBLH THROUGH SATURDAY
MORNING. FORECAST CONFIDENCE DECREASES AS WE TRANSITION INTO THE
AFTERNOON TIMEFRAME DUE TO UNCERTAINTY OF CONVECTIVE ACTIVITY.
VCTS HAVE BEEN HINTED AT FOR KIPL, BUT RAIN CHANCES CURRENTLY
STAND AT <10%. THIS TS SIGNAL HAS BEEN CONSISTENT FOR THE PAST
SEVERAL HOURS, SO AS TO NOT COMPLETELY IGNORE THE POTENTIAL, A
PROB30 GROUP HAS BEEN ADDED TO THE TAF. GUSTY
WESTERLY/SOUTHWESTERLY WINDS AND BRIEF REDUCTIONS IN VIS WILL BE
THE MAIN CONCERNS WITH ANY STORMS THAT COME TO FRUITION.
CONVECTION LOOKS AS IF IT WILL REMAIN OUTSIDE THE VICINITY OF
KBLH, BUT ANY CHANGES IN FORECAST GUIDANCE MAY YIELD THE ADDITION
OF A PROB30 OR VCTS INTO THAT TAF AS WELL.
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 MOST AFTERNOONS. 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 21 114 IN 2019 115 IN 1969 117 IN 1969
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 FRIDAY FOR AZZ530>555-559-
560.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT FRIDAY FOR CAZ562-565>567-
569-570.
SHORT TERM...BERISLAVICH
LONG TERM...BERISLAVICH
AVIATION...RW
FIRE WEATHER...BERISLAVICH/BENEDICT
CLIMATE...18
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