423
FXUS65 KPSR 221736
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1036 AM MST SAT AUG 22 2026
UPDATE
UPDATED AVIATION DISCUSSION.
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 HEATRISK ACROSS MUCH OF THE
CWA AND THEREFORE 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
EXPECTED ON 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 1735Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
UNCERTAINTY IN TSRA/SHRA COVERAGE AND CORRESPONDING GUSTY OUTFLOW
WINDS/WIND SHIFTS WILL BE THE PRIMARY FORECAST CHALLENGE THROUGH
SUNDAY AFTERNOON UNDER PERIODS OF MID/HIGH CLOUD DECKS. CONFIDENCE
IS GOOD THAT LIGHT E/SE OR VRB WINDS WILL SLOWLY TRANSITION TO
W/SW BY MID TO LATE AFTERNOON. TS DEVELOPMENT OVER HIGHER TERRAIN
AREAS MAY SEND GUSTY OUTFLOW WINDS TOWARDS THE PHOENIX TERMINALS
DURING THE LATE AFTERNOON/EARLY EVENING. CURRENT HI-RES GUIDANCE
SHOWS THE BEST COVERAGE OF SHOWERS AND STORMS WILL BE OVER
SOUTHWESTERN PINAL COUNTY, WHICH WOULD MAKE A SOUTHERLY OUTFLOW
THE MOST LIKELY/PREDOMINANT FAVORED DIRECTION. WHILE DIRECT TS
IMPACTS ARE NOT LIKELY AT THE TERMINALS, BRIEFLY GUSTY WINDS AND
DECAYING SHRA COULD AFFECT OPERATIONS EARLY-MID EVENING. IF MORE
CONCENTRATED STORMS CAN MATERIALIZE ALONG WITH MULTIPLE COLLIDING
OUTFLOW BOUNDARIES, BETTER CHANCES FOR ISOLATED TS DEVELOPMENT IN
LOWER ELEVATIONS WILL BE ENHANCED WITH STRONGER AND MORE PROLONGED
WIND GUSTS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR WEATHER ISSUES WILL EXIST THROUGH SUNDAY MORNING UNDER
MOSTLY CLEAR SKIES. TRENDS IN WINDS SHOULD BE SIMILAR TO THE PAST
24 HOURS, GENERALLY VARYING BETWEEN SE AND SW WITH EXTENDED
PERIODS OF NEARLY CALM CONDITIONS IN BETWEEN. TS ACTIVITY OVER THE
BAJA SPINE LATE THIS AFTERNOON MAY SEND AN OUTFLOW AND DECAYING
SHRA TOWARDS KIPL PRIOR TO SUNSET. CHANCES FOR DIRECT TSRA IMPACTS
ARE TOO LOW TO INCLUDE IN THE TAF, HOWEVER GUSTY SW WINDS JUSTIFY
A CONTINUED MENTION THROUGH THE EARLY EVENING.
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 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...WHITTOCK/18
FIRE WEATHER...BERISLAVICH/BENEDICT
CLIMATE...18
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page