596
FXUS65 KPSR 092059
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
159 PM MST FRI OCT 9 2026
KEY MESSAGES
- GENERALLY DRY CONDITIONS ALONG WITH TEMPERATURES AROUND 10
DEGREES ABOVE NORMAL WILL PERSIST TODAY.
- AN EXTREME HEAT WARNING REMAINS IN EFFECT FOR WESTERN IMPERIAL
COUNTY AND YUMA THROUGH THIS EVENING.
- AN UNSETTLED PATTERN WILL TAKE SHAPE THIS WEEKEND ALONG THE WEST
COAST AND DRAG THE REMNANTS OF TROPICAL CYCLONE RACHEL INTO THE
SOUTHWEST UNITED STATES, RESULTING IN HEIGHTENED CHANCES FOR
SHOWERS AND THUNDERSTORMS, WIDESPREAD GUSTY WINDS ON SUNDAY, AND
MUCH COOLER TEMPERATURES.
SHORT TERM /TODAY THROUGH SATURDAY/
FAIRLY QUIET CONDITIONS WILL ROUND OUT THE WORK WEEK BEFORE
SEVERAL WEATHER SYSTEMS INTERACT TO BRING UNSETTLED AND REGIONALLY
IMPACTFUL RAIN, WIND, AND SEVERE WEATHER POTENTIAL OVER THE
WEEKEND. TODAY, THE INFLUENCE OF BROAD ANTICYCLONIC FLOW REMAINS
OVER THE DESERT SOUTHWEST, WITH H5 HEIGHTS ANALYZED BETWEEN
584-586 DAM AT THIS HOUR. THOUGH HEIGHTS ARE GRADUALLY ERODING
TODAY, THERMAL PROFILES HAVE YET TO RESPOND MEANINGFULLY, AND THUS
850 MB TEMPERATURES UPWARDS OF 24C-26C (ABOVE THE 90TH PERCENTILE
OF CLIMATOLOGY) WILL CONTINUE TO SUPPORT HIGHS AROUND 10F ABOVE
DAILY NORMALS. YUMA AND EL CENTRO WILL ONCE AGAIN BE WITHIN A
COUPLE OF DEGREES OF DAILY RECORDS, WITH AREAS OF MAJOR HEATRISK
STILL CONTINUING. THEREFORE, EXTREME HEAT WARNINGS REMAIN IN
EFFECT FOR THE IMPERIAL VALLEY AND YUMA AREAS THROUGH THIS
EVENING.
OVER THE EASTERN PACIFIC, TROPICAL STORM RACHEL AND A SUBTROPICAL
SHORTWAVE/CUTOFF LOW HAVE BEGUN TO INTERACT WELL OFFSHORE THE
NORTHERN BAJA PENINSULA, TURNING THE TROPICAL SYSTEM'S TRACK
NORTHEASTWARD. SOUTH SOUTHWESTERLY MOIST FLOW WILL INCREASE IN
EARNEST SATURDAY AND ESPECIALLY BY SATURDAY NIGHT, WITH NAEFS MEAN
IVT NEAR/EXCEEDING CLIMATOLOGICAL MAXIMUM FOR THIS TIME OF YEAR.
MOISTURE AND UPPER LEVEL SUPPORT ARE LIKELY TO PEAK SATURDAY
NIGHT/EARLY SUNDAY MORNING AS THE REMNANTS OF RACHEL QUICKLY EJECT
NORTHEASTWARD NEAR/ALONG THE LOWER COLORADO RIVER, RESULTING IN
THE MOST WIDESPREAD COVERAGE OF SHOWERS AND STORMS. HOWEVER,
BEFORE THE PEAK TIMING FOR RAIN CHANCES, SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO ERUPT AS EARLY AS LATE SATURDAY
MORNING/SATURDAY AFTERNOON. STRONG, GUSTY WINDS AND LOCALIZED
HEAVY RAINFALL REMAIN THE MAIN THREATS WITH THIS INITIAL
ACTIVITY. SPC HAS ISSUED A MARGINAL RISK FOR SEVERE STORMS
SATURDAY INTO EARLY SUNDAY MORNING, AND INDICATES AT LEAST A VERY
LOW CHANCE FOR A TORNADO OR TWO. THE STRENGTHENING WIND FIELDS DO
SUPPORT THIS, WITH GFS BUFR SOUNDINGS ALSO SHOWING A BRIEF WINDOW
WITH HIGHER MUCAPE (UPWARDS OF 500-1000 J/KG), EBWD 30-40 KTS,
SFC-1 KM SHEAR ABOVE 10 KTS, AND LCLS LOWERING BELOW 2000 M.
SUPERCELLULAR STORMS MODES DO LOOK LIKE THEY WILL BE SUPPORTED BY
THE ENVIRONMENT, AT LEAST FOR A TEMPORARY WINDOW OF TIME SATURDAY
NIGHT INTO SUNDAY MORNING. HOWEVER, IT IS IMPORTANT TO KEEP IN
MIND THIS IS A HIGHLY VOLATILE FORECAST, WITH SMALL UPSTREAM
CHANGES RESULTING IN LARGE DOWNSTREAM FORECAST SHIFTS. REGARDLESS,
WITH ANY ORGANIZED STORM MODES THAT DEVELOP SATURDAY PM INTO
SUNDAY, THE PRIMARY AND MORE WIDESPREAD THREAT WILL BE FOR
DAMAGING WIND GUSTS.
LONG TERM /SUNDAY THROUGH THURSDAY/
THE MORE IMPACTFUL WEATHER IS EXPECTED ON SUNDAY AS THE REMNANTS
OF RACHEL MOVE THROUGH. ACCORDING TO THE LATEST OFFICIAL FORECAST
TRACK FROM THE NATIONAL HURRICANE CENTER, RACHEL IS EXPECTED TO
ACCELERATE NORTH-NORTHEASTWARD ALONG THE VICINITY OF THE LOWER
COLORADO RIVER VALLEY. AN AREA OF HEAVY RAINFALL IS LIKELY TO
FOLLOW ALONG AND JUST TO THE WEST OF WHERE RACHEL TRACKS. EVEN
THOUGH THE OFFICIAL NHC FORECAST HAS THE SYSTEM TRACKING ALONG THE
VICINITY OF THE LOWER COLORADO RIVER VALLEY SUGGESTING THAT THE
HEAVY RAINFALL MAY FALL ACROSS PORTIONS OF SOUTHEAST CA, THERE IS
A LOT OF SPREAD AMONGST THE GUIDANCE IN THE TRACK AS SOME
SOLUTIONS HAVE RACHEL TRACKING NEAR THE SOUTHERN CA COAST WHEREAS
OTHER SOLUTIONS HAVE THE SYSTEM TRACKING AS FAR EAST AS SOUTHWEST
AZ. THEREFORE, THE RAINFALL FORECAST IS STILL HIGHLY VOLATILE AND
COULD STILL SIGNIFICANTLY SHIFT DEPENDING ON THE EVENTUAL TRACK.
THE GREATER IMPACT WITH RACHEL WILL BE THE POTENTIAL FOR STRONG
WINDS AS A BELT OF STRONG 850 MB WINDS IN EXCESS OF 40-50 KTS IS
LIKELY TO SET UP ALONG THE EASTERN QUADRANT OF RACHEL WITH MUCH
OF THE GUIDANCE SHOWING GUSTS EXCEEDING 40-50 MPH ACROSS MUCH OF
SOUTHWEST INTO SOUTH-CENTRAL AZ, ESPECIALLY EARLY SUNDAY MORNING
THROUGH SUNDAY AFTERNOON. WIND GUSTS THIS HIGH COULD CERTAINLY
RESULT IN AREAS OF BLOWING DUST ACROSS THE DUST PRONE AREAS.
GIVEN THE STRONG WIND POTENTIAL, A WIND ADVISORY HAS BEEN HOISTED
FROM EASTERN RIVERSIDE AND IMPERIAL COUNTIES THROUGH ALL OF
SOUTHWEST AND SOUTH-CENTRAL AZ. IN ADDITION TO THE WIND THREAT,
THERE WILL ALSO BE THE POTENTIAL ALONG THE EASTERN QUADRANT FOR
MULTIPLE ROUNDS OF WIDELY SCATTERED SHOWERS AND STORMS TO
MATERIALIZE. THERE IS A POTENTIAL FOR SOME OF THESE STORMS TO
REACH SEVERE LEVELS GIVEN THAT STRONG VERTICAL SHEAR IN EXCESS OF
50 KTS WILL BE PRESENT, HOWEVER, THE SEVERE POTENTIAL WILL BE
DEPENDENT ON HOW MUCH INSTABILITY WILL BE PRESENT.
EVEN THOUGH THE REMNANTS OF RACHEL WILL BE WELL NORTH OF THE AREA BY
SUNDAY EVENING, UNSETTLED CONDITIONS WILL CONTINUE RIGHT THROUGH
EARLY NEXT WEEK AS THE MAIN WEST COAST TROUGH MOVES THROUGH THE
REGION BRINGING ADDITIONAL CHANCES FOR SHOWERS AND ISOLATED
THUNDERSTORMS, WITH THE HIGHEST CHANCES ACROSS THE FOOTHILLS AND
HIGHER TERRAIN AREAS TO THE NORTH AND EAST OF PHOENIX FROM UPSLOPE
FLOW. THEREAFTER, DRIER AND QUIETER WEATHER IS EXPECTED BY THE
MIDDLE OF THE WEEK AS THE MAIN TROUGH AXIS LIFTS TO THE NORTHEAST.
UNDER THE PRESENCE OF THE TROUGHING PATTERN, WELL-BELOW NORMAL
TEMPERATURES ARE EXPECTED DURING THE FIRST HALF OF NEXT WEEK WITH
LOWER DESERTS HIGHS GOING FROM THE LOW TO MID 80S ON SUNDAY TO
MOSTLY 70S TUESDAY AND WEDNESDAY. EARLY MORNING LOWS WILL ALSO
TAKE A TUMBLE WITH THE COOLEST MORNING EXPECTED ON WEDNESDAY AS
TEMPERATURES ARE EXPECTED TO BOTTOM OUT IN THE 50S ACROSS MUCH OF
THE REGION WITH EVEN SOME 40S ACROSS THE HIGHER TERRAIN AREAS.
AVIATION
UPDATED AT 1744Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
MAIN WEATHER CONCERN WILL BE VCSH AND -SHRA BEGINNING TO DEVELOP
NEAR THE END OF THE CURRENT TAF PACKAGE. UNTIL THEN, CONFIDENCE IS
EXCELLENT THAT EAST WINDS WILL PREVAIL WELL INTO THIS AFTERNOON
WITH POTENTIALLY A FEW LATE MORNING GUSTS 15-20KT, ALBEIT
SPATIALLY AND TEMPORALLY LIMITED. VERY LOW CONFIDENCE REMAINS
REGARDING WIND DIRECTIONS LATER THIS AFTERNOON AND EARLY EVENING
WHERE SOME TERMINALS MAY OBTAIN A LIGHT SOUTHERLY/SOUTHWESTERLY
CROSS RUNWAY COMPONENT, OR POTENTIALLY BECOME LIGHT AND VARIABLE
FOR A SHORT TIME. AREAS OF VIRGA AND POSSIBLY A FEW ISOLATED SHRA
ARE EXPECTED TO DEVELOP, FURTHER COMPLICATING WIND DIRECTIONS.
REGARDLESS, DIRECTIONS SHOULD QUICKLY SWITCH BACK TO E/SE BY THE
MID EVENING TIMEFRAME. CLOUD DECKS WILL BEGIN TO THICKEN TO BKN-
OVC AS THE SYSTEM APPROACHES BUT SHOULD REMAIN AOA 10KFT, OR AT
LEAST ABOVE VFR CONDITIONS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
MAIN WEATHER CONCERN WILL BE VCSH AND -SHRA BEGINNING TO DEVELOP
NEAR THE END OF THE CURRENT TAF PACKAGE. WIND SPEEDS WILL BE
MOSTLY AOB 10 KT AT BOTH TERMINALS. AT KIPL, CURRENT WESTERLY
WINDS WILL GO SOUTHERLY THIS AFTERNOON THEN BACK WESTERLY THIS
EVENING. AT KBLH, CURRENT NORTHWESTERLY WINDS WILL GO SOUTHERLY
LATE THIS MORNING, SOUTHWESTERLY THIS EVENING, THEN BACK SOUTHERLY
OVERNIGHT. GRADUALLY INCREASING MIDLEVEL CLOUD DECKS WITH BASES
AOA 10 KFT WILL CONTINUE TO DEVELOP THROUGHOUT THE PERIOD.
FIRE WEATHER
A MUCH MORE UNSETTLED WEATHER PATTERN WILL DEVELOP OVER THE
WEEKEND AS INCREASING MOISTURE ASSOCIATED WITH THE REMNANTS OF
TROPICAL STORM RACHEL BRINGS INCREASING RAIN CHANCES. THE CHANCES
FOR SHOWERS AND STORMS INCREASE STARTING SATURDAY
AFTERNOON/EVENING AND CONTINUES INTO SUNDAY WITH A GREATER THAN
50-70% CHANCE OF WETTING RAINFALL AREA WIDE. WINDS WILL ALSO
INCREASE SIGNIFICANTLY, ESPECIALLY LATE SATURDAY NIGHT THROUGH
SUNDAY WITH WIDESPREAD GUSTS EXCEEDING 30-40 MPH. WITH THE
INCREASING MOISTURE AND COOLER TEMPERATURES, MINRH VALUES WILL
INCREASE FROM 25-40% SATURDAY TO 45-70% ON SUNDAY ALONG WITH GOOD
TO EXCELLENT OVERNIGHT RECOVERIES. ANOTHER WEATHER SYSTEM WILL
BRING ADDITIONAL CHANCES FOR WETTING RAINFALL EARLY NEXT WEEK,
MAINLY FOR THE EASTERN DISTRICTS, BEFORE QUIETER WEATHER SETTLES
IN BY THE MIDDLE OF THE WEEK.
CLIMATE
RECORD HIGHS:
DATE YUMA EL CENTRO
---- ---- ---------
OCT 9 106 IN 2024104 IN 1996
PSR WATCHES/WARNINGS/ADVISORIES
AZ...EXTREME HEAT WARNING UNTIL 8 PM MST THIS EVENING FOR AZZ532.
WIND ADVISORY FROM 2 AM TO 5 PM MST SUNDAY FOR AZZ530>533-535-
536.
WIND ADVISORY FROM 8 AM TO 5 PM MST SUNDAY FOR AZZ534-537>563.
CA...EXTREME HEAT WARNING UNTIL 8 PM PDT THIS EVENING FOR CAZ566-567.
WIND ADVISORY FROM 2 AM TO 5 PM PDT SUNDAY FOR CAZ560>570.
SHORT TERM...WHITTOCK
LONG TERM...LOJERO
AVIATION...RYAN
FIRE WEATHER...WHITTOCK/LOJERO
CLIMATE...RW
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