185
FXUS65 KPSR 240924
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
224 AM MST WED DEC 24 2025
KEY MESSAGES
- A FLOOD WATCH AND WIND ADVISORY WILL BE IN EFFECT FOR THE
WESTERN, HIGHER ELEVATION PORTION OF JOSHUA TREE NATIONAL PARK
FOR MUCH OF TODAY.
- AN UNSETTLED WEATHER PATTERN WILL CARRY US THROUGH THE CHRISTMAS
HOLIDAY AND POTENTIALLY BEYOND, WITH GRADUALLY COOLING
TEMPERATURES AND A COUPLE PERIODS OF INCREASED RAIN CHANCES, ONE
EARLY TODAY AND ANOTHER THIS EVENING INTO THURSDAY.
SHORT TERM /TODAY THROUGH THURSDAY/
AN IMPRESSIVE UPPER LEVEL TROUGH IS CURRENTLY SITUATED OFF THE
WEST COAST WITH THE LOW CENTER WEST OF WASHINGTON AND OREGON AND
THE BASE OF THE TROUGH EXTENDING AS FAR SOUTH AS 20 DEGREES N
LATITUDE, OR EQUIVALENT TO THE SOUTHERN TIP OF BAJA. THE BASE OF
THE TROUGH IS ALSO SHOWING H5 HEIGHTS AT AROUND RECORD MIN FOR
THIS TIME OF YEAR AND THIS IS FORECAST TO CONTINUE THROUGH EARLY
THURSDAY.
FOR OUR REGION, WE REMAIN PARTIALLY COVERED BY RIDGING ACROSS
EASTERN PORTIONS OF THE REGION AND IT IS LIKELY TO STAY THAT WAY
AS THE DEEP TROUGH IS NOT EXPECTED TO MAKE ANY ADDITIONAL EASTWARD
PROGRESS. HOWEVER DUE TO THE CLOSE PROXIMITY OF THE TROUGH, WE
HAVE SEEN STRONG MOISTURE ADVECTION OVER THE PAST 12 HOURS PUSHING
PWATS TO OVER 1" ACROSS SOUTHEAST CALIFORNIA AND THROUGH MOST OF
THE ARIZONA LOWER DESERTS. THE MOISTURE ADVECTION IS ALSO
COINCIDING WITH THE PASSAGE OF A WEAK SHORTWAVE TROUGH WHICH HAS
HELPED TO SPARK OFF SOME LIGHT SHOWER ACTIVITY ACROSS PORTIONS OF
THE REGION. THIS SHOWER ACTIVITY IS FORECAST TO MOVE OVER EASTERN
PORTIONS OF ARIZONA LATER THIS MORNING BEFORE COMING TO AN END
DURING THE AFTERNOON HOURS.
THE NEXT ROUND OF PRECIPITATION WILL BE ASSOCIATED WITH THE MAIN
SHORTWAVE AND UPPER LEVEL JET MAX COMING ONSHORE IN CALIFORNIA,
BUT THE TRAJECTORY OF THIS BAND OF RAIN WILL LARGELY KEEP IT
NORTHWEST OF OUR AREA AS STRONG RAIN SHADOWING IS EXPECTED INTO
SOUTHEAST CALIFORNIA. HOWEVER, JOSHUA TREE NP MAY SEE PORTIONS OF
THIS BAND WITH A PERIOD OF MODERATE TO HEAVY RAINFALL POSSIBLE
FOCUSED FROM LATE AFTERNOON THROUGH AROUND MID EVENING. A FLOOD
WATCH REMAINS IN EFFECT FOR WESTERN PORTIONS OF JOSHUA TREE NP
FROM MID MORNING THROUGH THIS EVENING.
FOR THE REST OF THE AREA, ANOTHER BATCH OF RAIN IS LIKELY TO
DEVELOP BY LATE THIS EVENING, POTENTIALLY LASTING THROUGH THURSDAY
MORNING. THIS BAND IS LIKELY TO FORM SOMEWHERE ACROSS SOUTHWEST OR
SOUTH-CENTRAL ARIZONA IN AN AREA OF INCREASING UPPER LEVEL FORCED
ASCENT IN COMBINATION WITH UPSLOPE LOW AND MID LEVEL
SOUTHWESTERLY FLOW. THIS BAND WILL BE THE MAIN SHOT AT RAINFALL
ACROSS THE LOWER DESERTS AND IT MAY INVOLVE A PERIOD OF MODERATE
RAINFALL AND AMOUNTS OVER 0.25" IN SOME SPOTS. ADDITIONAL PERIODS
OF ISOLATED TO SCATTERED SHOWERS ARE LIKELY FOR THE REST OF
THURSDAY WITH THE MAIN AREA OF FOCUS OVER THE FOOTHILLS AND HIGHER
TERRAIN AREAS OF CENTRAL ARIZONA.
TEMPERATURES WILL TAKE A BIT OF A HIT TODAY INTO THURSDAY, BUT
DUE TO THE WARM NATURE OF THE WEATHER SYSTEM AND THE FACT THE
RIDGE IS STILL OVER EASTERN PORTIONS OF THE REGION, READINGS WILL
STAY NEAR 10 DEGREES ABOVE NORMALS.
LONG TERM /FRIDAY THROUGH TUESDAY/
THE DEEP PACIFIC TROUGH IS FORECAST TO WEAKEN QUICKLY GOING INTO
FRIDAY WITH THE SYSTEM BREAKING APART INTO TWO PIECES, ONE QUICKLY
EJECTING NORTHEASTWARD INTO THE NORTHERN ROCKIES AND ANOTHER
DRIFTING SOUTHWARD OFF THE COAST OF CALIFORNIA. DRIER AIR IS
EXPECTED TO PUSH INTO OUR REGION FROM THE SOUTHWEST FRIDAY INTO
THE WEEKEND WITH PWATS EVENTUALLY FALLING TO BELOW NORMAL ACROSS
AT LEAST WESTERN PORTIONS OF THE REGION. WHAT HAPPENS WITH THE
LEFTOVER ENERGY FROM THE TROUGH AND ITS TRACK IS STILL QUITE
UNCERTAIN, BUT TRENDS HAVE BEEN PULLING IT FARTHER AWAY FROM OUR
REGION. IF THIS CONTINUES, WE ARE LIKELY TO SEE A BREAK IN THE
RAIN CHANCES BY THE END OF FRIDAY AND LASTING THROUGH THE WEEKEND.
A COOLER AIR MASS SHOULD EVENTUALLY SETTLE IN OVER OUR REGION BY
FRIDAY AND LAST THROUGH THE WEEKEND WITH HIGHS DROPPING INTO THE
UPPER 60S TO THE LOWER 70S.
MODEL UNCERTAINTY INCREASES A GOOD DEAL BY EARLY NEXT WEEK AS THE
LEFTOVER TROUGH ENERGY MAY DRIFT BACK CLOSER TO OUR REGION,
POTENTIALLY BRINGING ANOTHER ROUND OF MOISTURE ADVECTION AND RAIN
CHANCES AS EARLY AS MONDAY AND LASTING THROUGH THE MIDDLE OF NEXT
WEEK.
AVIATION
UPDATED AT 0559Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
SHRA AND LOWERED CIGS THROUGH THE OVERNIGHT HOURS WILL BE THE
PRIMARY AVIATION WEATHER ISSUES DURING THE NEXT 24 HOURS. LIGHT
SHOWER ACTIVITY CONTINUES TO PUSH ACROSS PARTS OF THE PHOENIX
METRO THIS EVENING AND WILL CONTINUE INTO THE OVERNIGHT HOURS.
CIGS WILL LOWER DURING THIS TIME TO AT LEAST 7-8K FT, AND PERHAPS
AS LOW AS 5-6K FT AT TIMES. MODEL PROBABILITIES OF CIGS <6K FT
ARE ONLY AROUND 10%. THERE ALSO MAY BE FEW TO SCT LOWER CLOUDS
DOWN TO 3K FT AROUND MOUNTAIN FEATURES. SHOWERS SHOULD DIMINISH BY
15-17Z WITH SCT TO BKN 7-8K FT CLOUDS PERSISTING THROUGHOUT THE
REST OF THE DAY. WINDS THROUGH THE TAF PERIODS WILL PREDOMINANTLY
FAVOR THE EAST WITH SPEEDS MOSTLY AOB 10 KTS AND PERIODS OF
VARIABILITY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
SHOWER ACTIVITY HAS MOSTLY DIMINISHED ACROSS SOUTHEAST CALIFORNIA,
HOWEVER, LOWER CIGS WILL CONTINUE INTO THE OVERNIGHT HOURS. CIGS
DOWN TO AROUND 6-7 KFT ARE EXPECTED THROUGH TOMORROW MORNING.
WINDS WILL PREDOMINANTLY FAVOR THE E-SE AT KIPL, WHILE WINDS WILL
FAVOR THE E-NE AT KBLH BEFORE SWITCHING AROUND TO THE SOUTH LATE
WEDNESDAY MORNING. EXPECT PERIODS OF LIGHT AND VARIABLE WINDS TO
OCCUR AT BOTH TERMINALS THROUGHOUT THE PERIOD.
FIRE WEATHER
AN UNSETTLED WEATHER PATTERN WILL RESULT IN GRADUALLY COOLING
TEMPERATURES, INCREASED HUMIDITIES, AND PERIODIC CHANCES FOR
LIGHT TO MODERATE RAIN SHOWERS MAINLY THROUGH THURSDAY. MINRHS
WILL IMPROVE DRAMATICALLY TODAY, RANGING BETWEEN 40-60% AREAWIDE
AND STAYING ELEVATED INTO THE WEEKEND. WINDS WILL MOSTLY PREVAIL
OUT OF THE SOUTH TO SOUTHEAST THROUGH THURSDAY, WITH SPEEDS
GENERALLY 5-15 MPH, AND LOCALLY STRONGER GUSTS UPWARDS OF 20 TO 30
MPH ACROSS PORTIONS OF SOUTHWEST AZ AND SOUTHEAST CA TODAY.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...WIND ADVISORY FROM 8 AM TO 6 PM PST WEDNESDAY FOR CAZ560.
FLOOD WATCH FROM 9 AM PST WEDNESDAY THROUGH WEDNESDAY EVENING
FOR CAZ560.
SHORT TERM...KUHLMAN
LONG TERM...KUHLMAN
AVIATION...SMITH
FIRE WEATHER...KUHLMAN
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