657
FXUS65 KPSR 071756
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1056 AM MST WED OCT 7 2026
UPDATE
UPDATED 18Z AVIATION DISCUSSION.
KEY MESSAGES
- WELL ABOVE NORMAL TEMPERATURES WILL PERSIST THROUGH THE END OF THE
WORK WEEK 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 AREAS OF
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/
LATEST OBJECTIVE ANALYSIS SHOWS A BROAD RIDGE OF HIGH PRESSURE
OVER THE DESERT SOUTHWEST WITH A VERY WEAK DISTURBANCE NEAR THE AZ
AND UT BORDER. THIS DISTURBANCE COMBINED WITH ENOUGH MID-LEVEL
MOISTURE MAY HELP SPARK A FEW SHOWERS MAINLY OVER THE WHITE
MOUNTAINS THIS AFTERNOON AND THURSDAY AFTERNOON AS IT MOVES
SOUTHEASTWARD THROUGH THE FOUR CORNERS. OTHERWISE, WITH HIGH
PRESSURE IN CONTROL, DRY CONDITIONS WILL PREVAIL THROUGH MUCH OF
THE AREA THROUGH THE REST OF THE WEEK.
THE MAIN STORY THROUGH THE END OF THE WEEK WILL BE THE WELL-ABOVE
NORMAL TEMPERATURES. 500 MB HEIGHTS TODAY AND THURSDAY WILL RANGE
BETWEEN 586-590 DAM WITH 850 MB TEMPERATURES PEAKING BETWEEN 25-27C.
THIS WILL TRANSLATE TO SURFACE HIGH TEMPERATURES SURPASSING THE
TRIPLE DIGITS ACROSS MUCH OF THE LOWER DESERT COMMUNITIES WITH
READINGS RANGING BETWEEN 98-103 DEGREES ACROSS SOUTH-CENTRAL AZ
AND 104-108 DEGREES ACROSS THE WESTERN DESERTS. WITH TEMPERATURES
10-13 DEGREES ABOVE NORMAL AND NEARING DAILY RECORDS IN YUMA AND
EL CENTRO, AREAS OF MAJOR HEATRISK ARE EXPECTED AND THUS EXTREME
HEAT WARNINGS ARE IN EFFECT STARTING TODAY 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 WHEN THE
HOTTEST TEMPERATURES ARE EXPECTED. BY FRIDAY, EVEN THOUGH THE
RIDGE WILL WEAKEN AS A BROAD TROUGHING PATTERN BEGINS TO IMPINGE
INTO THE WEST COAST, LOW-LEVEL THERMAL PROFILES WILL STILL REMAIN
WARM ENOUGH FOR AFTERNOON HIGHS TO ONCE AGAIN SURPASS THE TRIPLE
DIGITS, WITH READINGS RANGING BETWEEN 98-101 DEGREES ACROSS SOUTH-
CENTRAL AZ AND 104-107 DEGREES ACROSS THE WESTERN DESERTS. WITH
AREAS OF MAJOR HEATRISK CONTINUING IN YUMA AND THE IMPERIAL
VALLEY, THE EXTREME HEAT WARNINGS WILL REMAIN IN EFFECT FOR THESE
AREAS.
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
LONG TERM...LOJERO
AVIATION...BERISLAVICH/18
FIRE WEATHER...LOJERO
CLIMATE...RW
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