044
FXUS65 KPSR 260013
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
513 PM MST FRI SEP 25 2026
UPDATE
UPDATED 00Z AVIATION DISCUSSION.
KEY MESSAGES
- QUIET CONDITIONS UNDER MOSTLY CLEAR SKIES CAN BE EXPECTED THROUGH
SATURDAY, WITH NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES.
- STARTING SUNDAY, MOISTURE WILL SURGE BACK INTO THE REGION WITH CLOUDY
SKIES AND EVENTUAL CHANCES FOR LIGHT RAIN LATER IN THE DAY.
- MONDAY AND TUESDAY MAY BRING GOOD CHANCES FOR RAIN AND POSSIBLY SOME
STRONG THUNDERSTORMS. HEAVY RAINFALL WILL ALSO BE POSSIBLE,
PARTICULARLY ACROSS THE ARIZONA HIGH TERRAIN.
- TEMPERATURES WILL COOL TO BELOW NORMAL DURING THE FIRST HALF OF
NEXT WEEK WITH HIGHS FROM THE MID EIGHTIES TO THE MID NINETIES.
SHORT TERM /TODAY THROUGH SATURDAY/
LATEST WATER VAPOR SATELLITE IMAGERY SHOWS THE MID-LEVEL LOW
FEATURE THAT BROUGHT UNSETTLED CONDITIONS DURING THE LAST 24-36
HOURS QUICKLY LIFTING TO THE NORTHEAST, WITH WESTERLY FLOW ALOFT
ENVELOPING MUCH OF THE REGION. THIS WESTERLY FLOW WILL ADVECT MUCH
DRIER AIR INTO THE REGION THROUGH SATURDAY WITH PWATS BOTTOMING
OUT UNDER ONE INCH. THEREFORE, EXPECT FAIRLY QUIET WEATHER WITH
MOSTLY CLEAR SKIES AND ZERO RAIN/STORM CHANCES. TEMPERATURES
DURING THE NEXT COUPLE OF DAYS WILL BE NEAR TO SLIGHTLY ABOVE
NORMAL. AFTERNOON HIGHS TODAY WILL TOP OUT IN THE MID TO UPPER 90S
ACROSS THE SOUTH-CENTRAL AZ LOWER DESERTS AND UPPER 90S TO LOWER
100S ACROSS THE WESTERN DESERTS, WITH SLIGHTLY WARMER READINGS FOR
SATURDAY.
LONG TERM /SUNDAY THROUGH THURSDAY/
A SIGNIFICANT WEATHER EVENT COULD BE SHAPING UP FOR NEXT MONDAY
INTO TUESDAY AS MODELS ARE BEGINNING TO COME TO A BETTER
CONSENSUS FOR A SEASONABLY STRONG UPPER LEVEL TROUGH MOVING
THROUGH OUR REGION. THE BIGGEST UNCERTAINTY STILL INVOLVES HOW
MUCH MOISTURE WILL BE AVAILABLE WHEN THE TROUGH DOES MOVE THROUGH,
BUT IT IS LOOKING MORE OPTIMISTIC COMPARED TO LAST NIGHT.
THIS NEXT EVENT IS EXPECTED TO START WITH STRONG UPPER LEVEL
MOISTURE ADVECTION FROM THE SOUTHWEST WHICH WILL ACTUALLY COME
FROM THE REMNANTS OF THE DECAYING TROPICAL SYSTEM ODALYS. ODALYS
IS FORECAST TO DRIFT NORTHWARD OVER THE NEXT DAY OR TWO BEFORE
GETTING ABSORBED INTO THE WESTERLIES AS A TROUGH DIGS
SOUTHEASTWARD OFF THE COAST OF CALIFORNIA. WE CAN ANTICIPATE
PLENTY OF HIGHER LEVEL MOISTURE AND CLOUDS OVERSPREADING OUR AREA
BEGINNING SATURDAY EVENING AND CONTINUING THROUGH MUCH OF SUNDAY.
THIS MOISTURE FETCH IS LIKELY TO BE VERY CONSISTENT FOR 18-24
HOURS WITH GRADUAL TOP-DOWN MOISTENING OF THE ATMOSPHERE. BY
SUNDAY MID TO LATE MORNING, SOME AREAS MAY START TO SEE SOME
SPRINKLES, OR EVEN VERY LIGHT RAIN, BUT NO MEASURABLE RAINFALL. IT
WOULD NOT BE SURPRISING TO SEE A FAIRLY NARROW BAND OF LIGHT RAIN
DEVELOPING BY SUNDAY EVENING SOMEWHERE ACROSS THE AREA, BUT
AMOUNTS ARE EXPECTED TO REMAIN VERY LIGHT.
ALSO STARTING SUNDAY, HURRICANE POLO IS FORECAST TO APPROACH
SOUTHERN BAJA BEFORE EVENTUALLY TRACKING TO THE NORTHEAST ACROSS
BAJA AND THE GULF OF CALIFORNIA MOST LIKELY LATER ON MONDAY. THE
LATEST NHC TRACK OF POLO KEEPS IT WELL TO OUR SOUTH AS IT IS
EXPECTED TO FALL APART QUICKLY AS IT MOVES ONSHORE INTO SOUTHERN
SONORA MEXICO. WE ARE NOT WORRIED ABOUT ANY DIRECT IMPACTS FROM
POLO, BUT IT IS BECOMING INCREASINGLY MORE LIKELY IT WILL HELP
DIRECT ADDITIONAL MOISTURE NORTHWARD INTO OUR REGION, SPECIFICALLY
IN THE LOW TO MID LEVELS. THIS MOISTURE WILL BE NECESSARY FOR ANY
DECENT RAINFALL TO OCCUR EARLY NEXT WEEK, SO ANY BIG DEVIATIONS IN
THE FORECAST MOISTURE WILL AFFECT OUR RAIN CHANCES FOR MONDAY AND
TUESDAY.
ALTHOUGH THE DETAILS ARE EXPECTED TO CHANGE, FORECAST CONFIDENCE
FOR A DECENT WEATHER/RAIN EVENT CONTINUES TO INCREASE. AS THE BULK
OF THE UPPER LEVEL MOISTURE FROM THE REMNANTS OF ODALYS MOSTLY
PUSHES INTO NEW MEXICO LATER ON SUNDAY, WE SHOULD BEGIN TO SEE
MOISTURE STREAM OUT OF THE SOUTH SOUTHWEST FROM POLO BY MONDAY
MORNING. THE BEST MOISTURE IS EXPECTED TO BYPASS OUR REGION TO THE
SOUTHEAST, BUT WE STILL SHOULD SEE GOOD MOISTURE WORKING INTO
MOST OF ARIZONA EARLY ON MONDAY, RIGHT AHEAD OF THE APPROACHING
UPPER LEVEL TROUGH. ENSEMBLE MEAN PWATS OF 200% OF NORMAL ARE
SHOWN FOR THE EASTERN 2/3RDS OF ARIZONA ON MONDAY WITH THE BULK OF
THIS MOISTURE FALLING IN THE LOW AND MID LEVELS, JUST WHERE IT
WOULD BE NEEDED FOR A DECENT RAIN EVENT.
THE UPPER LEVEL TROUGH WILL PLAY A VERY IMPORTANT ROLE EARLY NEXT
WEEK AS IT LOOKS LIKELY TO PROVIDE STRONG FORCING ON MONDAY AND
TUESDAY. UPPER LEVEL ASCENT IS EXPECTED TO BE QUITE GOOD, ALONG
WITH VERY GOOD 30-45 KTS OF SOUTHWESTERLY UPSLOPE FORCING WITHIN
THE MID LEVELS. IT IS STILL TOO EARLY TO HAVE A GREAT IDEA ON THE
DETAILS OF THE EVOLUTION OF THE RAINFALL, BUT IT COULD START IN
EARNEST BY MONDAY MORNING. NBM POPS INCREASE AREAWIDE BY MONDAY
MORNING WITH 30-50% CHANCES ACROSS THE WESTERN DESERTS TO 50-75%
FROM PHOENIX AND NORTH AND EAST OF PHOENIX. THESE POPS BASICALLY
HOLD THROUGH MONDAY NIGHT BEFORE GRADUALLY TAPERING OFF FROM WEST
TO EAST ON TUESDAY. WE MAY SEE FAIRLY STEADY UPSLOPE SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS SOUTH-CENTRAL AND EASTERN ARIZONA
MONDAY THROUGH EARLY TUESDAY.
WE ARE CURRENTLY LOOKING AT THREE POSSIBLE SCENARIOS FOR EARLY
NEXT WEEK. FIRST, AND THE MOST LIKELY OUTCOME (~60% CHANCE), IS
FOR A MODESTLY STRONG UPPER LEVEL TROUGH TO PUSH THROUGH MONDAY
INTO TUESDAY WITH VERY ADEQUATE, BUT NOT TROPICAL LEVEL MOISTURE
GETTING PULLED INTO OUR AREA RIGHT AHEAD OF THE PASSING TROUGH.
THIS SCENARIO WOULD SUPPORT WIDESPREAD RAINFALL AMOUNTS OF
0.10-0.30" OVER THE LOWER DESERTS TO 0.5-1.0" OVER THE HIGH
TERRAIN NORTH AND EAST OF PHOENIX. THIS SHOULD ALSO INVOLVE A
PERIOD OF STRONG THUNDERSTORMS DUE TO QUITE GOOD WIND SHEAR.
SECOND, (~20% CHANCE) WOULD KEEP THE BEST MOISTURE TO OUR SOUTH
AND/OR A MUCH WEAKER AND FASTER TROUGH. IN THIS SCENARIO, WE WOULD
EXPECT MUCH MORE SCATTERED RAINFALL WITH LOWER DESERT AMOUNTS
UNDER A 0.25" AND HIGHER TERRAIN AMOUNTS MORE LIKE 0.25-0.75". AT
THE OTHER END OF THE SPECTRUM (~20% CHANCE) WOULD LEAVE US WITH
THE UPPER END OF POTENTIAL MOISTURE COMBINING WITH A STRONGER AND
SLOWER TROUGH. THIS WOULD BRING A LONGER RAIN EVENT WITH LOWER
DESERT RAIN AMOUNTS AVERAGING FROM 0.2-0.5" OVER THE WESTERN
DESERTS TO 0.75-1.50" FOR THE SOUTH-CENTRAL ARIZONA LOWER DESERTS.
AS MUCH AS 2-3" WOULD ALSO BE VERY POSSIBLE OVER THE HIGH TERRAIN
NORTH AND EAST OF PHOENIX. THIS STRONGER EVENT IS ALSO LIKELY TO
INVOLVE A PERIOD OF STRONG TO SEVERE STORMS.
IT WILL BE ANOTHER DAY OR TWO UNTIL WE HAVE A GOOD IDEA ON THE
EXPECTED IMPACTS FOR THIS UPCOMING EVENT, BUT AS STATED ABOVE
THERE IS AT LEAST SOME POSSIBILITY OF A HIGH IMPACT EVENT. WE
WILL CONTINUE TO MONITOR THE MODEL TRENDS AND PROVIDE THE LATEST
UPDATES WITH THIS UPCOMING WEATHER EVENT.
TEMPERATURES ARE EXPECTED TO TAKE A BIG DIP EARLY NEXT WEEK WITH
LOWER DESERT HIGHS FALLING TO AS LOW AS THE MID 80S IN THE
PHOENIX AREA TO THE LOW TO MID 90S ACROSS THE WESTERN DESERTS.
ONCE THE WEATHER SYSTEM EJECTS TO THE EAST BY NEXT WEDNESDAY, WE
SHOULD FALL BACK INTO A DRIER AND WARMER PATTERN.
AVIATION
UPDATED AT 0015Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO AVIATION CONCERNS ARE EXPECTED DURING THE TAF PERIOD. WINDS
WILL FOLLOW FAMILIAR LIGHT AND DIURNAL TRENDS WITH SOME MOMENTS OF
VARIABILITY DURING DIRECTIONAL SHIFTS. A PERIOD OF SOUTHERLY
CROSSWINDS (KPHX AND KDVT) IS ALSO ANTICIPATED TOMORROW LATE
MORNING/EARLY AFTERNOON PRIOR TO THE WESTERLY SHIFT. SKIES WILL BE
MOSTLY CLEAR IN THE VICINITY OF THE TERMINALS THROUGH THIS
EVENING AHEAD OF HIGH CLOUDS MOVING IN EARLY TONIGHT.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION CONCERNS ARE EXPECTED DURING THE NEXT 24 HOURS. WINDS
WILL FAVOR LIGHT AND DIURNAL TRENDS, WITH PERIODS OF VRB
CONDITIONS TONIGHT INTO SATURDAY MORNING. CLEAR SKIES WILL GIVE
WAY TO INCREASING HIGH CLOUDS THIS EVENING.
FIRE WEATHER
MUCH DRIER AIR SETTLING INTO THE REGION WILL RESULT IN QUIET
WEATHER AND NEAR ZERO RAIN CHANCES THROUGH SATURDAY ALONG WITH
NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES. RAIN CHANCES WILL
INCREASE ONCE AGAIN STARTING SUNDAY AS MOISTURE LEVELS INCREASE.
THERE IS THE POTENTIAL FOR A MORE WIDESPREAD WETTING RAINFALL
EVENT EARLY NEXT WEEK. MINRHS TODAY WILL BOTTOM OUT BETWEEN 25-45%
ACROSS THE EASTERN DISTRICTS AND 15-25% ACROSS THE WESTERN
DISTRICTS BEFORE DROPPING FURTHER TO 15-25% IN MOST AREAS ON
SATURDAY. AS MOISTURE LEVELS INCREASE STARTING SUNDAY, MINRHS
WILL REBOUND ABOVE 20% ACROSS MOST AREAS. WINDS WILL GENERALLY
FOLLOW THE TYPICAL DIURNAL TENDENCIES WITH LIMITED TO NO AFTERNOON
GUSTS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...LOJERO
LONG TERM...KUHLMAN
AVIATION...BERISLAVICH/RW
FIRE WEATHER...LOJERO/KUHLMAN
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