992
FXUS65 KPSR 230955
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
255 AM MST SUN AUG 23 2026
KEY MESSAGES
- ISOLATED TO SCATTERED THUNDERSTORMS, SOME STRONG TO POSSIBLY
EVEN SEVERE, ARE EXPECTED THIS EVENING ACROSS SOUTH-CENTRAL
ARIZONA.
- INCREASINGLY LESS FAVORABLE CONDITIONS FOR THUNDERSTORMS WILL
DEVELOP STARTING MONDAY WITH VIRTUALLY NO CHANCES FOR RAIN FROM
TUESDAY THROUGH THE REST OF THE WEEK.
- HIGH TEMPERATURES WILL REACH OR EXCEED 110 DEGREES NEARLY EVERY
DAY THIS WEEK AND WILL BE NEAR DAILY RECORDS, WHILE MORNING
LOWS REMAIN UNUSUALLY WARM.
- EXTREME HEAT WARNINGS ARE IN EFFECT THROUGH SATURDAY WITH DAILY
MAJOR TO EXTREME HEATRISK.
SHORT TERM /TODAY THROUGH MONDAY/
TODAY COULD SHAPE UP TO BE ANOTHER SOMEWHAT BUSY MONSOON DAY, BUT
UNLIKE LAST WEDNESDAY MOISTURE AND THE AMOUNT OF INSTABILITY WILL
BE MORE LIMITED. ATMOSPHERIC CONDITIONS AT THE MOMENT ARE NOT
VERY CONDUCIVE FOR CONVECTION DUE TO THE LIMITED MOISTURE, BUT THE
UPPER LEVELS ARE SOMEWHAT FAVORABLE FOR DEVELOPMENT. THE
SUBTROPICAL HIGH HAS SHIFTED FAR ENOUGH TO THE EAST (EASTERN NEW
MEXICO/WESTERN TEXAS) TO DECREASE THE SUBSIDENCE INVERSION. AN
UPPER LEVEL TROUGH HAS ALSO MOVED IN ALONG THE WEST COAST PLACING
MUCH OF OUR REGION WITHIN OR NEAR THE MORE FAVORABLE RIGHT
ENTRANCE REGION OF A WEAK UPPER JET. SO, DESPITE THE OVERALL
MEAGER MOISTURE CURRENTLY IN PLACE, OTHER ATMOSPHERIC INGREDIENTS
ARE MORE FAVORABLE AND BETTER MOISTURE IS EXPECTED TO ADVECT
NORTHWARD TODAY POTENTIALLY PUTTING SOUTHERN AND CENTRAL ARIZONA
BACK IN THE GAME FOR MONSOON STORMS.
GIVEN THE ANTICIPATED SCENARIO FOR LATE THIS AFTERNOON AND
EVENING, WE ARE BECOMING MORE CONFIDENT IN OUR CHANCES FOR
ISOLATED TO SCATTERED THUNDERSTORMS. PART OF THIS CONFIDENCE COMES
FROM THE 06Z HRRR WHICH SHOWS STORMS DEVELOPING NORTH OF PHOENIX
AND OVER PIMA COUNTY LATE THIS AFTERNOON WITH BOTH CLUSTERS
SENDING OUTFLOWS TOWARD THE PHOENIX METRO. WITH FORECAST MUCAPES
NEAR 1000 J/KG AND CIN FALLING TO BELOW 100 J/KG LATE THIS
AFTERNOON, ANY DECENT OUTFLOW COLLISION SEEMS LIKELY TO SPARK OFF
ADDITIONAL STORM DEVELOPMENT. THE 06Z HRRR SHOWS THIS EXACT
PROGRESSION WITH STORMS DEVELOPING OVER OR NEAR THE PHOENIX METRO
EARLY THIS EVENING. ADDITIONALLY, SINCE MOISTURE WILL BE MORE
LIMITED, DCAPES WILL BE VERY HIGH (1700-2000 J/KG) SUPPORTING
STRONG TO LOCALLY SEVERE WIND GUSTS. FORECAST POPS HAVE BEEN
RAISED INTO A 20-30% RANGE, WHICH BETTER MATCHES THE LATEST HIGH-
RES GUIDANCE.
CONVECTIVE CHANCES FOR MONDAY ARE EVEN MORE UNCERTAIN AS GUIDANCE
GENERALLY SHOWS AT MOST A 10% CHANCE DESPITE MOISTURE AND
INSTABILITY BEING BETTER THAN TODAY. HOWEVER, SUBSIDENCE WILL BE
MUCH STRONGER ON MONDAY AS THE SUBTROPICAL RIDGE BEGINS TO MOVE
WESTWARD BACK INTO OUR REGION. WE WILL HAVE TO WAIT UNTIL TONIGHT
TO HAVE A BETTER IDEA ON THE STORM POTENTIAL FOR MONDAY, BUT IT
DOES SEEM TO BE CONSIDERABLY LOWER THAN THIS AFTERNOON/EVENING.
TEMPERATURES TODAY WILL AGAIN BE RIGHT NEAR RECORD HIGHS WITH
LOWER DESERT READINGS FROM 110-115 DEGREES. THE INCREASED BOUNDARY
LAYER MOISTURE EXPECTED FOR MONDAY SHOULD HOLD DAYTIME HIGHS DOWN
A BIT WITH NBM FORECAST HIGHS CURRENTLY BETWEEN 106-111 DEGREES,
BUT HEAT INDICES WILL MOSTLY MATCH WHAT ARE EXPECTED TODAY.
LONG TERM /TUESDAY THROUGH SATURDAY/
FORECAST ATTENTION TURNS AWAY FROM MONSOON STORM POTENTIAL AND
BACK TOWARD THE EXTREME HEAT CONDITIONS STARTING TUESDAY. THE
SUBTROPICAL HIGH CENTER WILL CONTINUE TO SHIFT WESTWARD INTO OUR
REGION INTO THE MIDDLE PART OF THE WEEK WITH THE CENTER LIKELY
SETTLING SOMEWHERE OVER SOUTHERN ARIZONA FROM WEDNESDAY THROUGH AT
LEAST FRIDAY OR SATURDAY. FORECAST H5 HEIGHTS ARE ALSO SHOWN TO
REACH 594-597DM FOR THE LATTER HALF OF THE WEEK WHICH PLACES IT
JUST SHY OF CLIMATOLOGICAL RECORDS FOR LATE AUGUST. NBM
TEMPERATURE GUIDANCE REMAINS QUITE CONSISTENT SHOWING HIGHS RISING
INTO A 112-116 DEGREE RANGE FOR THE LATTER HALF OF THIS WEEK AS
CONDITIONS DRY OUT. DAILY TEMPERATURE RECORDS IN PHOENIX WILL
CONTINUE TO BE IN JEOPARDY THROUGH THE ENTIRE WEEK, BUT ARE LIKELY
TO FALL SHORT IN YUMA AND EL CENTRO. ONCE THE HIGH CENTER MOVES
OVERHEAD BY WEDNESDAY, RAIN CHANCES WILL ESSENTIALLY GO TO 5% OR
LESS. AS OF NOW, CONDITIONS FOR ANY MONSOON STORM ACTIVITY DO NOT
LOOK GOOD THROUGH NEXT WEEKEND.
AVIATION
UPDATED AT 0910Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE MAIN AVIATION CONCERN WILL BE THE GUSTY OUTFLOWS AND POTENTIAL
FOR REDUCED VISIBILITIES AND THUNDERSTORMS. UNTIL THEN EASTERLY
WINDS WILL CONTINUE THROUGH THE OVERNIGHT AND MORNING HOURS
SHIFTING OUT OF THE WEST NEAR 19-20Z THIS AFTERNOON. ANOTHER ROUND
OF ACTIVITY IS EXPECTED TO DEVELOP TO THE NORTHEASTERN HIGH
TERRAIN AND IN SOUTHERN PARTS OF AZ THIS AFTERNOON AND EVENING.
OUTFLOW BOUNDARIES WILL LIKELY DEVELOP AND PUSH INTO THE METRO
FROM THE NE AND S. KPHX AND KIWA WILL LIKELY BE AFFECTED BY THE
SOUTHERN OUTFLOW BETWEEN 04-07Z, WHILE MODELS SHOW KSDL AND KDVT
AFFECTED BY THE NORTHEASTERN OUTFLOW A LITTLE EARLIER, NEAR 01-05Z
TONIGHT. THIS IS REFLECTED IN THE MOST RECENT TAF PACKAGE BUT IS
SUBJECT TO CHANGE IN FUTURE PACKAGES DEPENDING ON HOW MODELS
HANDLE EACH OUTFLOW ACCORDINGLY. CHANCES FOR DIRECT TS IMPACTS
THIS EVENING REMAIN AT UP TO 30% CHANCE BUT ENOUGH UNCERTAINTY
REMAINS THAT NO PROB30 WAS INTRODUCED AT THIS POINT IN TIME. FEW-
SCT MID/HIGH CLOUD DECKS WILL BE COMMON THROUGHOUT THE PERIOD.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED THROUGH THE TAF PERIOD.
KIPL WILL MAINTAIN WEST WINDS THROUGH THE OVERNIGHT PERIOD THEN
GOING SE'RLY BY 15Z. TS ACTIVITY OVER THE BAJA SPINE MAY SEND AN
SOUTHWESTERLY OUTFLOW INTO KIPL BY THE LATE AFTERNOON HOURS, WITH
A LESS THAN 20% CHANCE FOR DIRECT TS IMPACTS. KBLH WILL SWING
BETWEEN SOUTH TO SW'RLY WINDS, FAVORING THE SW. OTHERWISE FEW-SCT
MID TO HIGH CLOUD DECKS WILL BE COMMON THROUGH THE PERIOD.
FIRE WEATHER
HOT TEMPERATURES WILL PREVAIL THROUGH THE ENTIRE WEEK WITH SHOWER
THUNDERSTORM CHANCES MAINLY TODAY AND POSSIBLY MONDAY. STRONG
GUSTY WINDS WILL BE POSSIBLE LATE THIS AFTERNOON AND EVENING WITH
ANY THUNDERSTORMS, WHILE CHANCES FOR WETTING RAINS WILL REMAIN
BELOW 20%. MINIMUM RHS WILL IMPROVE THROUGH MONDAY WITH READINGS
OF 15-25% TODAY AND 20-30% MONDAY, BEFORE DROPPING BACK INTO THE
TEENS INTO THE MIDDLE PART OF THE WEEK. TEMPERATURES WILL BE
AROUND 5-10 DEGREES ABOVE NORMAL, WITH LOWER DESERT HIGHS
ECLIPSING 110 DEGREES NEARLY EVERY AFTERNOON. 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 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
AUG 29 116 IN 2023 117 IN 1954 117 IN 2005
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...KUHLMAN
LONG TERM...KUHLMAN
AVIATION...LOJERO/RYAN
FIRE WEATHER...KUHLMAN
CLIMATE...18/KUHLMAN
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