623
FXUS65 KPSR 052159
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
259 PM MST WED AUG 5 2026
KEY MESSAGES
- EXTREME HEAT CONDITIONS WILL PERSIST THROUGH THE WEEKEND WITH
TEMPERATURES HOVERING NEAR TO SEVERAL DEGREES ABOVE NORMAL
WHILE HUMIDITY VALUES REMAIN HIGHER THAN NORMAL.
- SHOWER AND THUNDERSTORM CHANCES WILL FAVOR EAST AND SOUTHEAST
ARIZONA THE REMAINDER OF THE WEEK WITH GUSTY OUTFLOW WINDS AND
BLOWING DUST THE MOST LIKELY IMPACTS FOR SOUTH-CENTRAL ARIZONA.
- SHOWER AND THUNDERSTORM CHANCES START TO INCREASE ACROSS THE
LOWER DESERTS THIS WEEKEND AND INTO NEXT WEEK.
SHORT TERM /TODAY THROUGH THURSDAY/
EARLY THIS AFTERNOON, WATER VAPOR SATELLITE IMAGERY AND OBJECTIVE
ANALYSIS SHOW THE SUBTROPICAL RIDGE STRETCHED ACROSS THE
SOUTHWESTERN CONUS WITH H5 HEIGHTS OF 592-594 DM. THE SPC
MESOANALYSIS SHOWS THAT PWATS ACROSS THE REGION ARE IN THE
1.4-1.8" RANGE ACROSS OUR AREA. THE SUBTROPICAL HIGH IN
COMBINATION WITH THE INCREASED MOISTURE TRAPPED UNDER IT WILL
CONTINUE TO LEAD TO HOT AND HUMID CONDITIONS ACROSS THE REGION
OVER AT LEAST THE NEXT COUPLE OF DAYS. THE INCREASED MOISTURE
(120-130% OF NORMAL) WILL ALSO LEAD TO DAILY SHOWER AND
THUNDERSTORMS CHANCES, MAINLY ACROSS THE HIGHER TERRAIN AREAS.
WITH THE HIGH PRESSURE STILL OVERHEAD AFTERNOON HIGH TEMPERATURES
ARE STILL FORECASTED TO BE AT LEAST A FEW DEGREES ABOVE NORMAL TODAY
AND TOMORROW. AFTERNOON HIGH TEMPERATURES ARE FORECASTED TO BE IN
THE 107-112 DEGREE RANGE ACROSS THE LOWER DESERTS AND IN THE UPPER
90S TO LOW 100S ACROSS THE HIGHER TERRAIN. TEMPERATURES EARLY THIS
AFTERNOON ARE VERY SIMILAR TO THAT OF 24 HOURS AGO, SO AFTERNOON
HIGH TEMPERATURES WILL LIKELY BE SIMILAR TO THAT OF YESTERDAY,
ESPECIALLY WITH THE CLOUD COVER HANGING ON ACROSS MUCH OF THE CWA
LIKE YESTERDAY. THIS CLOUD COVER IS EXPECTED TO CLEAR BY THE LATE
AFTERNOON/EARLY EVENING HOURS. IF THERE IS ENOUGH BREAKS IN THE
CLOUDS THIS AFTERNOON I WOULDN'T BE SHOCKED TO SEE AFTERNOON HIGHS A
FEW DEGREES WARMER THAN YESTERDAY. WITH THE INCREASED LOW LEVEL
MOISTURE DEW POINTS ARE MOSTLY IN THE 60S ACROSS THE CWA, WITH SOME
LOCATIONS SEEING DEW POINTS IN THE LOW 70S. THESE HIGH DEW POINTS
ARE LEADING TO HOT "FEELS LIKE" TEMPERATURES WITH MAX "FEELS LIKE"
TEMPERATURES FORECASTED TO BE IN THE 110-120 DEGREE RANGE ACROSS THE
LOWER DESERTS TODAY AND TOMORROW. DUE TO THESE HOT TEMPERATURES
PAIRED WITH THE HOT "FEELS LIKE" TEMPERATURES, THE EXTREME HEAT
WARNING REMAINS IN EFFECT. SIMILAR CONDITIONS ARE EXPECTED AGAIN
TOMORROW.
WHILE CONVECTIVE POTENTIAL REMAINS HIGH ACROSS THE HIGHER TERRAIN
IN EASTERN AZ WITH STORMS ALREADY FIRING UP ALONG THE MOGOLLON
RIM. ACTIVITY HAS BEEN SLOWER TO FIRE UP IN SE AZ. CONVECTIVE
POTENTIAL, HOWEVER, REMAINS LOW ACROSS THE SOUTH-CENTRAL LOWER
DESERTS. AND WITH THE LINGERING CLOUD COVER THIS AFTERNOON
CONVECTIVE POTENTIAL CONTINUES TO DECREASE FOR THIS EVENING
ACROSS THE LOWER DESERTS. HOWEVER, THE CAMS CONTINUE TO SHOW AT
LEAST SOME POTENTIAL FOR SHOWERS AND STORMS TO DEVELOP ACROSS THE
LOWER DESERTS OF SOUTH- CENTRAL AZ LOWER DESERTS MAINLY BETWEEN
03-07Z THIS EVENING. CAMS CONTINUE TO SHOW MUCAPE VALUES AROUND
1000-1500 J/KG, HOWEVER THEY ALSO SHOW CIN AROUND 100-200 J/KG.
THE STORMS ACROSS THE MOGOLLON RIM AND POTENTIAL STORMS ACROSS SE
AZ ARE EXPECTED TO SEND MULTIPLE OUTFLOWS INTO THE LOWER DESERTS.
CONFIDENCE IS HIGH ON AN OUTFLOW FROM THE E/NE. HOWEVER, WITH THE
SLOWER DEVELOPMENT ACROSS SE AZ CONFIDENCE IN AN OUTFLOW FROM THAT
DIRECTION IS LOWER. IF WE DO GET AN OUTFLOW FROM THE SE, IT WOULD
BE STRONGER AND PRODUCE AREAS OF BLOWING DUST AND REDUCED
VISIBILITY. IF WE GET MULTIPLE OUTFLOWS IT MAY BE ENOUGH TO BREAK
THE CAP AND FIRE UP SOME STORMS, ESPECIALLY IF OUTFLOWS COLLIDE.
DESPITE THE HIGH AMOUNT OF MUCAPE, OVERCOMING THE CIN WILL BE THE
MAIN ISSUE FOR STORM DEVELOPMENT ACROSS THE LOWER DESERTS THIS
EVENING.
TOMORROW, THE SUBTROPICAL HIGH WILL START TO STRENGTHEN AGAIN, WITH
H5 HEIGHTS INCREASING TO AROUND 595-597 DM, AND THE CENTER WILL
SHIFT TO BE MORE OVER NORTHERN ARIZONA. AS A RESULT SOME DRIER AIR
WILL MOVE INTO THE REGION, WITH PWATS FORECASTED TO DECREASE FROM
AROUND 1.4-1.8" TODAY DOWN TO AROUND 1.2-1.5" TOMORROW. THEREFORE,
THERE WILL BE A SLIGHTLY LOWER CHANCE OF SHOWERS AND STORMS ACROSS
THE HIGHER TERRAIN IN EASTERN AZ, WITH LITTLE TO NO CHANCE ACROSS
THE LOWER DESERTS.
LONG TERM /FRIDAY THROUGH TUESDAY/
STRENGTHENING OF THE RIDGE IS FORECAST THROUGH FRIDAY BEFORE
GRADUALLY WEAKENING THIS WEEKEND INTO MONDAY. GUIDANCE AGREES H5
HEIGHTS WILL RISE TO 596-598DM ON FRIDAY BEFORE DROPPING BACK TO 594-
596DM BY SUNDAY. THE STRENGTH OF THIS RIDGE WILL EASILY BE AROUND
THE 99TH PERCENTILE OF CLIMATOLOGY ACROSS THE REGION ON FRIDAY,
DROPPING BACK TO 90-97TH PERCENTILE ON SUNDAY. DUE TO THE STRENGTH
OF THE RIDGE AND SOME SLIGHT DRYING, TEMPERATURES ARE FORECAST TO
PEAK ON FRIDAY AND/OR SATURDAY WITH HIGHS 110-115 DEGREES. SURFACE
DEW POINTS SHOULD FALL BACK INTO THE UPPER 50S TO LOWER 60S DURING
THIS TIME, BUT IT WILL STILL FEEL SOMEWHAT HUMID AS HEAT INDICES
COULD REACH AS HIGH AS 115-120 DEGREES ACROSS THE LOWER DESERTS OF
SOUTHEAST CALIFORNIA. THERE WAS ENOUGH CONFIDENCE IN GUIDANCE TO
ALSO EXTEND THE EXTREME HEAT WARNING THROUGH SUNDAY AS THE
CONVECTIVE POTENTIAL SHOULD BE FAIRLY LIMITED. THE STRENGTH OF THE
HIGH AND SLIGHT DIP IN MOISTURE IS EXPECTED KEEP CIN VALUES QUITE
HIGH ACROSS THE AREA, ESPECIALLY OVER THE LOWER DESERTS. HIGHER
TERRAIN AREAS OF EASTERN ARIZONA WILL KEEP DAILY 15-30% CHANCE POPS,
WHILE THE PHOENIX AREA MOSTLY STAY BETWEEN 10-15%.
BY EARLY NEXT WEEK, MODELS SHOW THE RIDGE WEAKENING AGAIN, WHILE
MOST LIKELY STAYING CENTERED TO OUR NORTH. THIS SHOULD ALLOW FOR
BETTER MONSOON STORM CHANCES WITH MODELS LEANING TOWARD SOME
IMPROVING MOISTURE AND BETTER UPPER LEVEL SUPPORT. NBM/WPC POPS SEEM
TOO HIGH FOR SUNDAY AT 30-40% OVER CENTRAL AND EASTERN ARIZONA, BUT
THOSE CHANCES MAY BE MORE REASONABLE FOR MONDAY AND/OR TUESDAY OF
NEXT WEEK. TEMPERATURES WILL ALSO DRIFT LOWER EARLY NEXT WEEK DUE TO
THE WEAKENING OF THE RIDGE AND WITH MORE CONVECTIVE ACTIVITY IN THE
AREA. THE LATEST NBM SHOWS TEMPERATURES BACK INTO THE NORMAL RANGE
BY AROUND MONDAY OR TUESDAY.
AVIATION
UPDATED AT 1700Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
UNCERTAINTY IN STRONG, GUSTY OUTFLOW WINDS AND THE POTENTIAL FOR
SCATTERED TSRA THIS EVENING ARE THE MAIN FORECAST CHALLENGES.
CONFIDENCE IS VERY GOOD THAT WEST WINDS WILL PREVAIL THROUGH THE
AFTERNOON WITH THE POTENTIAL FOR SOME 15-20KT LATE AFTERNOON GUSTS.
TSRA SHOULD INITIALLY FORM WELL EAST AND SOUTH OF TERMINALS THIS
AFTERNOON WITH MULTIPLE OUTFLOW BOUNDARIES FOCUSED TOWARDS THE METRO
THIS EVENING. MODEL INDICATIONS SUGGEST AN INITIAL EASTERLY WIND
SHIFT FOLLOWED BY A SOUTHERLY OUTFLOW BOUNDARY. THIS SECONDARY
COLLISION MAY ALLOW SCATTERED TSRA TO DEVELOP MID EVENING WITH
ADDITIONAL ERRATIC WIND DIRECTIONS AND LOWERED VSBY DUE TO IMPORTED
BLDU. CONFIDENCE IN THIS OUTCOME IS ONLY LOW TO MODERATE WITH PROB30
APPROPRIATE FOR THIS SCENARIO.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR WEATHER ISSUES WILL EXIST THROUGH THURSDAY AFTERNOON UNDER
PERIODS OF MID/HIGH CLOUD DECKS. TRENDS IN WINDS WILL BE SIMILAR TO
THE PAST 24 HOURS WITH A PREFERENCE TOWARDS A SOUTHERLY DIRECTION
AND MODEST AFTERNOON/EARLY EVENING GUSTS.
FIRE WEATHER
HOT TEMPERATURES WILL CONTINUE THROUGH THE WEEKEND WITH FAIRLY
ELEVATED HUMIDITIES, BUT SHOWERS AND THUNDERSTORMS WILL MOSTLY
REMAIN OVER FAR EASTERN AND SOUTHEASTERN ARIZONA. GUSTY OUTFLOW
WINDS ARE LIKELY TO IMPACT THE SOUTH-CENTRAL ARIZONA LOWER DESERTS
AGAIN TODAY WITH A 10-30% CHANCE OF STORMS. MINRHS WILL REMAIN
ELEVATED AT 20-30% THROUGH THURSDAY BEFORE DROPPING BACK INTO THE
TEENS OVER THE LOWER DESERTS FRIDAY INTO SATURDAY. OVERNIGHT
RECOVERIES WILL REMAIN FAIR TO GOOD AT 40-60%. OUTSIDE OF STORM
OUTFLOWS, WINDS WILL MOSTLY FOLLOW DIURNAL PATTERNS, WITH UPSLOPE
AFTERNOON GUSTS OF 15-20 MPH AT TIMES.
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...BERISLAVICH
LONG TERM...KUHLMAN
AVIATION...18
FIRE WEATHER...BERISLAVICH/KUHLMAN
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