448
FXUS65 KPSR 210857
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
157 AM MST FRI AUG 21 2026
KEY MESSAGES
- HIGHS WILL RETURN TO AROUND 110 DEGREES TODAY ACROSS THE LOWER
DESERTS AND CONTINUE INTO EARLY NEXT WEEK BEFORE HEATING UP TO
AROUND 114 DEGREES DURING THE LATTER HALF OF NEXT WEEK.
- EXTREME HEAT WARNINGS HAVE BEEN EXTENDED THROUGH NEXT FRIDAY
EVENING DUE TO CONTINUED AREAS OF MAJOR HEATRISK THROUGH EARLY
NEXT WEEK AND INCREASING TO WIDESPREAD EXTREME HEATRISK DURING
THE LATTER HALF OF NEXT WEEK.
- ISOLATED THUNDERSTORMS ARE EXPECTED TO REMAIN CONFINED TO THE
HIGH TERRAIN THROUGH AT LEAST SATURDAY.
SHORT TERM /TODAY THROUGH SATURDAY/
THE SUBTROPICAL HIGH IS CURRENTLY CENTERED OVER THE FOUR CORNERS
REGION EARLY THIS MORNING AND MODELS ARE IN GOOD AGREEMENT THAT IT
WILL SLOWLY PROGRESS EASTWARD THROUGH TOMORROW AND EVENTUALLY
SETTLE OVER EASTERN CO/NM. THIS WILL CAUSE WINDS OVER OUR REGION
TO BECOME MORE SOUTHERLY, WHICH WILL USHER IN MUCH DRIER AIR.
PWATS EARLY THIS MORNING CURRENTLY RANGE FROM 1.0-1.5" OVER OUR
AREA AND MODELS SHOW PWATS DECREASING TO 0.9-1.3". MODELS ALSO
SHOW MIXING RATIOS AS LOW AS 7-8 G/KG. THIS WILL RESULT IN DRY
CONDITIONS ACROSS THE LOWER DESERTS AND ONLY SLIGHT CHANCES FOR
SOME ISOLATED SHOWERS AND STORMS OVER THE HIGHER TERRAIN AREAS.
MODELS DO SHOW SLIGHT CHANCES OF A WEAK OUTFLOW BOUNDARY TRYING TO
MOVE INTO THE LOWER DESERTS. HOWEVER, ANY OUTFLOWS ARE EXPECTED TO
WASH OUT AS THEY MOVE OFF THE TERRAIN, SIMILAR TO LAST NIGHT.
DESPITE THE HIGH SHIFTING EASTWARD OVER THE NEXT COUPLE OF DAYS,
MODELS SHOW 500MB HEIGHTS OF 593-596DM OVER OUR AREA. SKIES WILL
RETURN TO MOSTLY CLEAR BY THIS AFTERNOON, WHICH WILL ALLOW
TEMPERATURES TO HEAT BACK UP TODAY AND ARE FORECASTED TO BE AROUND
110-114 (98-108) DEGREES ACROSS THE LOWER DESERTS (HIGHER
TERRAIN) THIS AFTERNOON. SIMILAR TEMPERATURES ARE FORECASTED FOR
SATURDAY AND MAY BE A DEGREE OR TWO WARMER THAN TODAY IN SOME
LOCATIONS. THESE HOT TEMPERATURES WILL RESULT IN WIDESPREAD MAJOR
HEATRISK ACROSS THE LOWER DESERTS AND IN SOME AREAS OF THE HIGHER
TERRAIN (SPECIFICALLY THE SAN CARLOS AREA). AS A RESULT, THE
EXTREME HEAT WARNING FOR THE LOWER DESERTS AND SAN CARLOS AREA
REMAINS IN EFFECT. MAKE SURE TO PRACTICE SMART HEAT SAFETY BY
DRINKING PLENTY OF WATER AND ELECTROLYTES AND LIMITING YOUR TIME
OUTDOORS, ESPECIALLY DURING THE AFTERNOONS.
LONG TERM /SUNDAY THROUGH NEXT FRIDAY/
MODEL UNCERTAINTY REMAINS QUITE HIGH FOR THE FIRST HALF OF NEXT
WEEK AS THE POSITION OF THE HIGH IS LIKELY TO SET UP SOMEWHERE
OVER EASTERN NEW MEXICO AND WESTERN TEXAS BY MONDAY. THIS
POSITION CAN CAUSE HIGHER UNCERTAINTY IN MOISTURE LEVELS FOR OUR
AREA WITH THE LATEST GUIDANCE TRYING TO ADVECT SOME MOISTURE INTO
OUR AREA BY SUNDAY OR MONDAY, BUT NBM FORECAST POPS ARE AT MOST
10-15% FOR THE LOWER DESERTS. AT THIS POINT, WE COULD CONTINUE TO
SEE MOSTLY SLIGHT CHANCES FAVORING THE HIGH TERRAIN INTO EARLY
NEXT WEEK, BUT IF MOISTURE DOES EVENTUALLY IMPROVE ENOUGH STORM
CHANCES ARE LIKELY TO BE HIGHER THAN WHAT THE NBM IS DEPICTING.
ANOTHER WILDCARD WILL BE THE POTENTIAL INFLUENCE OF AN UPPER LEVEL
TROUGH THAT MAY ATTEMPT TO MOVE INTO WESTERN PORTIONS OF OUR
REGION SUNDAY INTO MONDAY. IF THIS OCCURS, IT MAY BE ENOUGH TO
IMPROVE CONVECTIVE POTENTIAL ACROSS SOUTHEAST CALIFORNIA AND
WESTERN ARIZONA FOR SUNDAY AND/OR MONDAY. BY TUESDAY, DRIER AIR
WILL FILTER BACK INTO THE REGION AS THE SUBTROPICAL HIGH BEGINS TO
RETROGRADE BACK OVER OUR REGION. THIS WILL END LIMIT LOW END RAIN
CHANCES TO THE HIGHER TERRAIN AREAS WITH THE LOWER DESERTS
REMAINING DRY. BY THE LATTER HALF OF NEXT WEEK, THE NBM SHOWS POPS
BEING CONFINED TO THE MOGOLLON RIM WITH NO CHANCES FOR OUR CWA.
TEMPERATURES ARE EXPECTED TO CONTINUE TO BE MORE INFLUENCED BY THE
STRONG SUBTROPICAL HIGH AS H5 HEIGHTS HOVER BETWEEN 593-596DM
ACROSS THE DESERT SOUTHWEST THROUGH EARLY NEXT WEEK. DAYTIME HIGHS
ARE NOT EXPECTED TO CHANGE MUCH FROM SUNDAY TO MONDAY, BARRING
ANY SIGNIFICANT CHANGE WITH THE CONVECTIVE CHANCES. AS MENTIONED
ABOVE, BY TUESDAY THE SUBTROPICAL HIGH WILL START TO RETROGRADE
BACK TO THE WEST AND CENTER WILL EVENTUALLY SETTLE OVER AZ/NM
DURING THE LATTER HALF OF THE WORKWEEK. THE HIGH WILL ALSO
STRENGTHEN TO AROUND 595-597DM 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) WILL
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 FORECASTED
FOR THE MAJORITY OF THE CWA FOR THE LATTER HALF OF THE WORKWEEK.
DUE TO THESE HOT TEMPERATURES AND WIDESPREAD EXTREME HEATRISK
EXPECTED NEXT WEEK, THE EXTREME HEAT WARNING HAS BEEN EXTENDED
THROUGH NEXT FRIDAY.
AVIATION
UPDATED AT 0510Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR AVIATION WEATHER CONCERNS ARE EXPECTED THROUGHOUT THE TAF
PERIOD UNDER FEW-SCT MID/HIGH CLOUD DECKS. THE OVERALL WIND
PATTERN WILL FOLLOW THE TYPICAL DIURNAL TENDENCIES WITH OVERALL
SPEEDS REMAINING AOB 10 KTS. WIND DIRECTIONS DO BECOME A BIT MORE
UNCERTAIN FRIDAY EVENING AS THERE ARE SOME INDICATIONS FROM THE
HI-RES GUIDANCE THAT STORM ACTIVITY ACROSS SOUTHEAST AZ MAY SEND
A DECAYING OUTFLOW BOUNDARY INTO THE AREA, WITH A POTENTIAL WIND
SHIFT OUT OF THE SOUTH-SOUTHWEST TO SOUTH. HOWEVER, AT THIS TIME,
NO SIGNIFICANT GUSTS ARE ANTICIPATED IF THE OUTFLOW COMES TO
FRUITION.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION WEATHER CONCERNS ARE EXPECTED THROUGHOUT THE TAF
PERIOD UNDER FEW-SCT MID/HIGH CLOUD DECKS. WINDS WILL GENERALLY
FLUCTUATE OUT OF THE SOUTHEAST TO SOUTHWEST DIRECTION WITH SPEEDS
UNDER 12 KTS. PERIODS OF LIGHT VARIABILITY WILL BE COMMON DURING
THE EARLY MORNING HOURS.
FIRE WEATHER
DRIER AIR WILL FILTER INTO THE REGION TODAY AND SATURDAY WITH
EVEN LOWER CHANCES FOR RAIN WHILE TEMPERATURES HEAT BACK UP TO
5 TO 8 DEGREES ABOVE NORMAL. ONLY SLIGHT CHANCES FOR ISOLATED
STORMS EXISTS OVER THE HIGHER TERRAIN THROUGH SATURDAY. MINRHS OF
15-25% TODAY DECREASE TO 12-20% TOMORROW. MINRH THEN INCREASES
AGAIN TO 15-25% SUNDAY AND MONDAY BEFORE DECREASING BACK TO 10-20%
BEGINNING TUESDAY. OVERNIGHT RECOVERY WILL GENERALLY BE IN THE
30-60% RANGE, WITH THE BEST NIGHT BEING SUNDAY NIGHT. WINDS
SHOULD OVERALL FOLLOW THE TYPICAL DIURNAL TENDENCIES WITH SOME
MODEST AFTERNOON UPSLOPE GUSTINESS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST FRIDAY FOR AZZ530>544-546-
548>551-553>555-559-560.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT FRIDAY FOR CAZ562-565>567-
569-570.
SHORT TERM...BERISLAVICH
LONG TERM...BERISLAVICH/KUHLMAN
AVIATION...LOJERO
FIRE WEATHER...BERISLAVICH
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