876
FXUS65 KPSR 092336
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
435 PM MST FRI OCT 9 2026
UPDATE
UPDATED AVIATION
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 2335Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE PRIMARY WEATHER ISSUE WILL BE SHRA MOVING INTO THE AREA SATURDAY
AFTERNOON AS MIDLEVEL CIGS THICKEN AND LOWER. CONFIDENCE IN WIND
DIRECTION EARLY THIS EVENING IS LOW, GENERALLY OSCILLATING 140V200
UNTIL REVERTING BACK TO AN E/SE COMPONENT. CIGS WILL ALSO DEVELOP IN
A 10-15K FT AGL LAYER WITH WIDESPREAD VIRGA DEVELOPING, WHICH COULD
LOCALLY AFFECT WIND SPEEDS AND DIRECTIONS BRIEFLY. WINDS SHOULD
MAINTAIN A SE TRAJECTORY SATURDAY, HOWEVER SHRA ENTERING THE AREA IN
THE AFTERNOON MAY CREATE ERRATIC DIRECTIONS. COVERAGE OF SHRA
APPEARS LOW ENOUGH TO PRECLUDE A PREDOMINANT MENTION, AND WILL
ADVERTISE A PROLONGED PERIOD OF VCSH. A FEW EMBEDDED TSRA WILL ALSO
BE POSSIBLE, BUT ODDS ONLY JUSTIFY A PROB30 MENTION AT THIS TIME.
SUNDAY OUTLOOK: HIGH IMPACT WEATHER STILL APPEARS TO BE ARRIVING AT
ALL TERMINALS SUNDAY MID/LATE MORNING THROUGH THE AFTERNOON.
SHRA/TSRA SHOULD SURGE INTO THE AREA WITH GUSTY SOUTH WINDS AND
MVFR/IFR CIGS. THE LOWER CIGS AND TSRA THREAT SHOULD BE RATHER SHORT
LIVED OVER A 3-4 HOUR WINDOW LATE MORNING THROUGH EARLY AFTERNOON
BEFORE LIFTING OUT OF THE AERODROME SPACE. HOWEVER, VERY STRONG S/SW
WINDS WILL FILL IN BEHIND THE SHRA WITH GUSTS 35KT OR HIGHER
THROUGHOUT THE AFTERNOON.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
SHOWERS MOVING INTO THE AREA SATURDAY MORNING AND AFTERNOON WITH
THICK MIDLEVEL CIGS WILL BE THE MAIN WEATHER ISSUE THIS TAF PERIOD.
CONFIDENCE IS VERY GOOD THAT WINDS WILL SWING FROM A SOUTHERLY
DIRECTION TO MORE OF A W/SW DIRECTION THROUGH THE EVENING AS MIDLEVEL
CLOUD DECK BEGIN TO INCREASE. SCATTERED SHRA WILL BEGIN TO MOVE INTO
THE REGION SATURDAY MORNING AS CIGS LOWER TO AROUND 10K FT AGL,
THOUGH COVERAGE ONLY DICTATES A VCSH MENTION. WHILE AN ISOLATED TSRA
IS POSSIBLE, ODDS ARE TOO LOW TO INCLUDE IN THIS TAF PACKAGE. FAR
MORE IMPACTFUL WEATHER WILL ARRIVE AFTER THE TAF TIME FRAME SATURDAY
NIGHT THROUGH SUNDAY AFTERNOON.
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...18
FIRE WEATHER...WHITTOCK/LOJERO
CLIMATE...RW
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