632
FXUS65 KPSR 072048
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
148 PM MST WED OCT 7 2026
KEY MESSAGES
- WELL ABOVE NORMAL TEMPERATURES WILL PERSIST THROUGH THE END OF
THE WORKWEEK AS LOWER DESERT HIGHS TOP OUT IN THE TRIPLE DIGITS.
- AN EXTREME HEAT WARNING REMAINS IN EFFECT FOR PORTIONS OF
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA TODAY THROUGH FRIDAY
AS TEMPERATURES WARM TO NEAR RECORD LEVELS, RESULTING IN MAJOR
HEATRISK.
- DRY CONDITIONS WILL PERSIST THROUGH AT LEAST THE END OF THE
WORKWEEK BEFORE A MUCH MORE UNSETTLED PATTERN ARRIVES BY THE
WEEKEND WITH MUCH COOLER TEMPERATURES AND INCREASING RAIN
CHANCES.
SHORT TERM /TODAY THROUGH FRIDAY/
CURRENT REGIONAL ANALYSIS REVEALS BROAD, BUT SOMEWHAT MESSY, RIDGING
OVER MUCH OF THE WESTERN CONUS, WHILE A WEAK EMBEDDED SHORTWAVE
CONTINUES TO MEANDER AROUND THE FOUR CORNERS. THE LATTER OF THESE
FEATURES, COMBINED WITH SOME RELATIVELY DECENT MID-LEVEL MOISTURE,
MAY AID IN THE DEVELOPMENT OF SOME VERY ISOLATED AND AND
INCONSEQUENTIAL SHOWERS OVER THE WHITE MOUNTAINS THIS AFTERNOON
AS IT SLIDES DOWN INTO EASTERN ARIZONA. OUTSIDE OF THAT HOWEVER,
DOMINANT HIGH PRESSURE WILL PROMOTE DRY CONDITIONS ACROSS THE
DESERT SOUTHWEST AS WE TRANSITION TO THE BACK HALF OF THE WEEK.
THE MAIN FOCUS IN THE NEAR TERM WILL BE THE CONTINUATION OF WELL-
ABOVE NORMAL TEMPERATURES. WITH HEIGHTS ALOFT TOPPING OUT BETWEEN
587-590 DAM THIS AFTERNOON, A GOOD 1-1.5 STANDARD DEVIATION ABOVE
CLIMATOLOGICAL NORMAL FOR EARLY OCTOBER, ALONG WITH 850MB
TEMPERATURES PEAKING BETWEEN 25-27C, TRIPLE DIGIT HIGHS WILL BE
QUITE COMMON THE NEXT FEW DAYS ACROSS THE LOWER DESERTS. READINGS
FOR SOUTH-CENTRAL ARIZONA WILL RANGE BETWEEN 98-103 DEGREES WHILE
SLIGHTLY HOTTER OBSERVATIONS NEAR 102-109 DEGREES CAN BE EXPECTED
ACROSS THE WESTERN DESERTS. ALTHOUGH THESE VALUES ARE NOT ATYPICAL
DURING LATE SPRING AND SUMMER, THEY WILL STILL BE 10 OR SO
DEGREES ABOVE NORMAL FOR THIS OF YEAR WHILE NEARING DAILY RECORDS
AT YUMA AND EL CENTRO. THIS WILL RESULT IN AREAS OF MAJOR HEATRISK
AND THUS EXTREME HEAT WARNINGS HAVE NOW GONE INTO EFFECT FOR THE
IMPERIAL VALLEY AND YUMA, WITH THE WARNING EXPANDED TO INCLUDE THE
LOWER COLORADO RIVER VALLEY AND ALONG I-8 IN YUMA COUNTY FOR
THURSDAY.
ALTHOUGH THE RIDGE WILL BEGIN TO WANE FRIDAY, THERMAL PROFILES
WILL BE SLOW TO RESPOND WHICH WILL ALLOW FOR ONE MORE DAY OF
TRIPLE DIGIT HEAT. READINGS WILL NOT BE MUCH DIFFERENT FROM THE
DAYS PRIOR, BUT PERHAPS A DEGREE OR TWO "COOLER" FROM THURSDAY.
THIS WILL ALLOW FOR THE CESSATION OF AT LEAST PART OF THE EXTREME
HEAT WARNING, BUT WITH LINGERING MAJOR HEATRISK FOR THE IMPERIAL
VALLEY AND YUMA, THESE AREAS WILL REMAIN WITHIN SAID WARNING TO
FINISH OUT THE WORKWEEK.
LONG TERM /SATURDAY THROUGH TUESDAY/
A SIGNIFICANT PATTERN SHIFT IS STILL ANTICIPATED THIS WEEKEND
THROUGH EARLY NEXT WEEK AS THE MOST OF THE DETERMINISTIC AND
ENSEMBLE MODEL GUIDANCE CONTINUES TO SHOW A BROAD TROUGHING
PATTERN SETTING UP ACROSS MUCH OF THE WESTERN THIRD OF THE CONUS.
GUIDANCE CONTINUES TO SHOW A NORTHERN STREAM TROUGH DIVING INTO
THE PACIFIC NORTHWEST ON SATURDAY BEFORE SINKING SOUTHWARD OVER CA
ON SUNDAY. MEANWHILE, A MORE SOUTHERN STREAM SHORTWAVE TROUGH IS
LIKELY TO MOVE INTO THE SUBTROPICAL EASTERN PACIFIC AND PICK UP
THE REMNANTS OF HURRICANE RACHEL AS IT MOVES NORTHEASTWARD AND
PHASES WITH THE WEST COAST TROUGH. AS THIS WHOLE PATTERN EVOLUTION
TAKES SHAPE, THE INCREASING SOUTH TO SOUTHWESTERLY FLOW ALOFT
WILL ADVECT MOISTURE INTO THE DESERT SOUTHWEST STARTING SATURDAY,
WITH MOST OF THE MOISTURE AT FIRST CONFINED IN THE MID TO UPPER-
LEVELS BEFORE BETTER LOW-LEVEL MOISTURE MOVES IN ON SUNDAY AS THE
REMNANTS OF RACHEL GETS PULLED IN. COINCIDENTALLY, RAIN CHANCES
WILL BE ON THE INCREASE AS EARLY AS SATURDAY AFTERNOON ACROSS
SOUTH-CENTRAL AZ BEFORE PEAKING SUNDAY INTO MONDAY ACROSS MUCH OF
THE REGION WITH THE ARRIVAL OF BETTER LOW-LEVEL MOISTURE. THERE
CONTINUES TO BE A GREAT DEAL OF UNCERTAINTY IN RAINFALL AMOUNTS AS
IT WILL BE DEPENDENT ON THE OVERALL TRACK OF THE REMNANTS OF
RACHEL AND HOW IT INTERACTS WITH THE WEST COAST TROUGH. IT WILL
LIKELY TAKE AT LEAST ANOTHER COUPLE OF DAYS TO GET A BETTER IDEA
ON THE RAINFALL PERSPECTIVES AS GUIDANCE COMES INTO BETTER
AGREEMENT ON HOW THE OVERALL PATTERN SHAPES UP. IN ADDITION TO THE
RAINFALL POTENTIAL, WINDS WILL BE ANOTHER HAZARD TO CONTEND WITH
AS THE COMBINATION OF THE HEIGHT FALLS FROM THE TROUGH AND REMNANT
CIRCULATION OF RACHEL WILL LIKELY RESULT IN WIDESPREAD BREEZINESS.
AS 500 MB HEIGHTS LOWER WITH THE APPROACHING TROUGH ALONG WITH
THE INCREASING CLOUD COVER AND MOISTURE, MUCH COOLER TEMPERATURES
ARE EXPECTED THIS WEEKEND INTO EARLY NEXT WEEK. AFTERNOON HIGHS
ACROSS THE LOWER DESERTS WILL GO FROM MID TO UPPER 90S ON SATURDAY
TO LOW TO MID 80S BY MONDAY AND MAY POTENTIALLY DROP EVEN LOWER
ON TUESDAY WITH MANY LOCATIONS STUCK IN THE LOW 80S.
AVIATION
UPDATED AT 1756Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO WEATHER CONCERNS ARE EXPECTED THROUGH THAT TAF PERIOD. WINDS
WILL BE TYPICAL DIURNAL TRENDS WITH PERIODS OF VRB CONDITIONS
DURING TRANSITIONAL PERIODS. WINDS SPEEDS WILL REMAIN AOB 8KTS.
FEW MID TO HIGH CLOUDS ARE EXPECTED TO CLEAR BY THIS EVENING.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO WEATHER CONCERNS ARE EXPECTED THROUGH THE TAF PERIOD. EXTENDED
PERIODS OF LIGHT AND VARIABLE WINDS WILL BE COMMON WITH A
TENDENCY TOWARDS FOR NORTHERLY COMPONENT BACKING TO A WEST
TRAJECTORY AFTER SUNSET. WIND SPEEDS WILL BE AOB 7 KT. SKIES WILL
REMAIN CLEAR.
FIRE WEATHER
DRY CONDITIONS ALONG WELL-ABOVE NORMAL TEMPERATURES WILL CONTINUE
THROUGH THE END OF THE WORK WEEK AS LOWER DESERT HIGHS REACH INTO
THE TRIPLE DIGITS. WINDS THROUGH THURSDAY WILL GENERALLY BE LIGHT
AND DIURNALLY DRIVEN BEFORE INCREASING FRIDAY INTO THIS WEEKEND.
AFTERNOON MINRHS THROUGH THE END OF THE WORK WEEK WILL RANGE
BETWEEN 15-25% WITH FAIR TO GOOD OVERNIGHT RECOVERIES (35-60%). A
MORE UNSETTLED WEATHER PATTERN IS EXPECTED THIS WEEKEND THROUGH
EARLY NEXT WEEK AS A WEATHER SYSTEM AFFECTS THE AREA WITH MUCH
COOLER TEMPERATURES ALONG WITH INCREASING MOISTURE AND CHANCES FOR
WETTING RAINFALL.
CLIMATE
RECORD HIGHS:
DATE YUMA EL CENTRO
---- ---- ---------
OCT 7 111 IN 2024105 IN 1991
OCT 8 107 IN 1996 106 IN 1996
OCT 9 106 IN 2024104 IN 1996
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST FRIDAY FOR AZZ532.
EXTREME HEAT WARNING FROM 10 AM TO 8 PM MST THURSDAY FOR AZZ530-
536.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT FRIDAY FOR CAZ566-567.
EXTREME HEAT WARNING FROM 10 AM TO 8 PM PDT THURSDAY FOR CAZ569-
570.
SHORT TERM...LOJERO/RW
LONG TERM...LOJERO
AVIATION...BERISLAVICH/18 FIRE
WEATHER...LOJERO
CLIMATE...RW
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