985
FXUS65 KPSR 091744
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1044 AM MST FRI OCT 9 2026
UPDATE
UPDATED 18Z AVIATION DISCUSSION.
KEY MESSAGES
- 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.
- A MUCH MORE UNSETTLED WEATHER PATTERN IS EXPECTED THIS WEEKEND THROUGH
EARLY NEXT WEEK AS A SERIES OF WEATHER SYSTEMS WILL AFFECT THE
REGION RESULTING IN MUCH COOLER TEMPERATURES, BREEZY TO WINDY
CONDITIONS, AND HEIGHTENED RAIN CHANCES.
SHORT TERM /TODAY THROUGH SATURDAY/
LATEST OBJECTIVE ANALYSIS SHOWS A RIDGE OF HIGH PRESSURE STILL
PREVAILING ACROSS THE REGION. HOWEVER, THE RIDGE WILL BE IN A
WEAKENING PHASE THROUGHOUT THE DAY AS A TROUGHING PATTERN BEGINS
TO MATERIALIZE ALONG THE WEST COAST. UNDER THE INFLUENCE OF THE
RIDGE, ANOTHER DAY OF DRY CONDITIONS ALONG WITH WELL-ABOVE NORMAL
TEMPERATURES CAN BE EXPECTED AS LOWER DESERT HIGHS ONCE AGAIN
REACH INTO THE TRIPLE DIGITS WITH READINGS RANGING BETWEEN 99-103
DEGREES ACROSS SOUTH-CENTRAL AZ AND 103-107 DEGREES ACROSS THE
WESTERN DESERTS. EL 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.
BIG CHANGES ARE THEN ON TAP STARTING ON SATURDAY AS A LARGE NORTHERN
STREAM TROUGH DIVES INTO THE PACIFIC NORTHWEST WHILE, ACROSS THE
EASTERN PACIFIC, TROPICAL STORM RACHEL WILL RECURVE NORTHEASTWARD
TOWARDS THE NORTHERN BAJA PENINSULA AS IT IS PICKED UP BY A CUTOFF
LOW. SOUTH TO SOUTHWEST FLOW ALOFT WILL ADVECT SIGNIFICANT MOISTURE
INTO THE REGION AS PWATS SURGE ABOVE 200% SATURDAY AFTERNOON/EVENING
ACCORDING TO THE EPS AND GEFS. THIS MOISTURE SURGE IN ADDITION TO
INCREASING UPPER-LEVEL FORCING FROM THE APPROACHING TROUGH WILL
RESULT IN AREAS OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
BREAKING OUT STARTING SATURDAY AFTERNOON AND CONTINUING THROUGH
SATURDAY EVENING THROUGH THE OVERNIGHT. LATEST HI-RES GUIDANCE
SHOWS ACTIVITY BREAKING OUT FIRST ACROSS CENTRAL AND SOUTHERN AZ
WITH ANOTHER AREA OF ACTIVITY MATERIALIZING FURTHER WEST ACROSS
PORTIONS OF SOUTHWEST AZ AND SOUTHEAST CA. GUSTY WINDS AND BRIEF
PERIODS OF MODERATE TO LOCALLY HEAVY RAINFALL WILL BE THE MAIN
THREATS. WITH THE INCREASE IN CLOUD COVER AND HEIGHTS ALOFT
LOWERING FROM THE APPROACHING TROUGH, AFTERNOON HIGH TEMPERATURES
WILL BE ABOUT 10 DEGREES COOLER THAN TODAY AS READINGS TOP OUT IN
THE LOW TO MID 90S ACROSS MUCH OF THE LOWER DESERTS.
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
DRY CONDITIONS ALONG WELL-ABOVE NORMAL TEMPERATURES WILL CONTINUE
TODAY AS LOWER DESERT HIGHS REACH INTO THE TRIPLE DIGITS.
AFTERNOON MINRHS TODAY WILL RANGE BETWEEN 15-25%. WINDS TODAY
WILL REMAIN MOSTLY LIGHT ACROSS MUCH OF THE AREA. A MUCH MORE
UNSETTLED WEATHER PATTERN THEN DEVELOPS 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 CAZ564-565-569-
570.
SHORT TERM...LOJERO
LONG TERM...LOJERO
AVIATION...RYAN
FIRE WEATHER...LOJERO
CLIMATE...RW
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