293
FXUS65 KPSR 110524
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1024 PM MST WED SEP 10 2025
UPDATE
06Z AVIATION DISCUSSION
KEY MESSAGES
- AFTER ANOTHER MODERATE HEAT RISK DAY TODAY ACROSS THE SOUTH-
CENTRAL ARIZONA LOWER DESERTS, TEMPERATURES WILL BE COOLING TO
SLIGHTLY BELOW NORMAL OVER THE NEXT COUPLE OF DAYS.
- BREEZY CONDITIONS ARE EXPECTED AT TIMES TODAY AND THURSDAY WITH
PEAK WIND GUSTS IN THE AFTERNOON HOURS AT AROUND 25 MILES PER
HOUR.
- ASIDE FROM SOME SLIGHT CHANCES FOR RAIN ACROSS THE EASTERN
ARIZONA HIGH TERRAIN THROUGH THE END OF THE WORK WEEK, DRY
CONDITIONS ARE EXPECTED INTO NEXT WEEK.
SHORT TERM /TODAY THROUGH THURSDAY/
THE UPPER LEVEL PATTERN IS CHARACTERIZED BY A BROAD CLOSED LOW
CENTERED OVER NORCAL ACCORDING TO LATEST 500 MB RAP ANALYSIS,
CAUSING RIDGING TO SET UP DOWNSTREAM OVER THE CENTRAL CONUS, WITH
THE CENTER OF AN ANTICYCLONE OVER WEST TX/CHIHUAHUA. ONCE AGAIN THIS
MORNING, AN INVERSION INDICATIVE OF LARGE SCALE SUBSIDENCE
(ASSOCIATED WITH THE ANTICYCLONIC FLOW) WAS PRESENT JUST BELOW 500
MB IN THE 12Z PHOENIX SOUNDING, THOUGH IT DID NOT APPEAR AS
PROMINENT AS IT WAS YESTERDAY. PERHAPS MORE IMPORTANT TO INHIBITING
CONVECTIVE POTENTIAL TODAY IS A VERY DRY LAYER OF AIR SHOWN IN THE
12Z PHOENIX AND MODELED SOUNDINGS ABOVE THE SUBSIDENCE INVERSION. AS
A RESULT OF THE UPPER LEVEL PATTERN, FLOW ALOFT HAS TURNED SOUTHWEST
OVER THE WESTERN CWA AND MORE SO OUT OF THE SOUTH FOR THE EASTERN
CWA, SUCH THAT A SHALLOW LAYER OF MIDLEVEL MOISTURE IS STREAMING
INTO EASTERN AZ FROM SONORA, ALLOWING FOR SSW TO NNE ORIENTED
STREETS OF CUMULUS TO FORM DOWNSTREAM OF PROMINENT TERRAIN FEATURES.
EMBEDDED WITHIN THESE STREETS, A FEW ISOLATED SHOWERS AND WEAK
THUNDERSTORMS HAVE FORMED, MOSTLY EAST OF TUCSON, WITH ONLY WEAK
RADAR ECHOES OBSERVED SO FAR OVER THE HIGH TERRAIN OF SOUTHERN GILA
COUNTY. SOME STRONGER ELEVATED SHOWERS, PERHAPS EVEN A FEW WEAK
STORMS MAY FORM THROUGH THE REST OF THE AFTERNOON INTO THE EARLY
EVENING OVER THE HIGH TERRAIN EAST OF PHOENIX, WITH THE MAIN THREAT
BEING LOCALLY STRONG, GUSTY WINDS. ELSEWHERE, EXPECT DRY AND BREEZY
CONDITIONS THIS AFTERNOON, WITH GUSTS COMMONLY REACHING BETWEEN 20-
30 MPH.
THURSDAY, ENSEMBLES CONTINUE TO ADVERTISE THE UPPER LOW WEAKENING
SOMEWHAT AND SHIFTING OVER CENTRAL CA/SOUTHERN NEVADA, RESULTING IN
CONTINUED BREEZY AFTERNOON CONDITIONS AS WINDS ALOFT REMAIN ELEVATED
AND SIMILAR SHOWER/STORM CHANCES OVER THE HIGH TERRAIN EAST OF
PHOENIX. AS HEIGHTS ALOFT CONTINUE TO FALL, EXPECT HIGHS TO DROP
INTO A NEAR NORMAL RANGE FOR THE PHOENIX METRO (UPPER 90S TO LOWER
100S) AND SLIGHTLY BELOW NORMAL FOR THE WESTERN DESERTS (MIDDLE TO
UPPER 90S), RESULTING IN ONLY MINOR HEATRISK AREAWIDE.
LONG TERM /FRIDAY THROUGH TUESDAY/
MODEL GUIDANCE CONTINUES TO SHOW A WEAK SHORTWAVE TROUGH WITHIN
THE BROADER PACIFIC TROUGH PASSING THROUGH OUR REGION ON FRIDAY.
THE EASTERN ARIZONA HIGH TERRAIN MAY AGAIN SEE SOME ISOLATED RAIN
CHANCES FRIDAY, BUT POPS MOSTLY REMAIN BELOW 20%. DRIER AIR IS
SEEN SURGING IN BEHIND THIS SHORTWAVE TROUGH, FINALLY DROPPING
SURFACE DEW POINTS ACROSS SOUTH-CENTRAL AND EASTERN ARIZONA TO
BELOW 50 DEGREES FRIDAY AFTERNOON AND THEN INTO THE 30S ON
SATURDAY. THE COMING WEEKEND LOOKS VERY DRY UNDER CLEAR SKIES AS
THE TROUGH EXITS WELL TO THE NORTHEAST OF THE REGION LEAVING
BEHIND ZONAL FLOW TO WEAK RIDGING.
TEMPERATURES FRIDAY AND THROUGH THE WEEKEND WILL BE BELOW NORMAL
WITH HIGHS MOSTLY IN THE MID TO UPPER 90S ACROSS THE LOWER DESERTS
AND LOWS FROM THE MID 60S (RURAL AREAS) TO THE LOW 70S. ENSEMBLES
MOSTLY AGREE ON ANOTHER PACIFIC TROUGH MOVING INLAND AT SOME POINT
EARLY NEXT WEEK, BUT THEY DIFFER EXACTLY WHERE. THIS UNCERTAINTY
MEANS THE TEMPERATURE FORECAST FOR THE FIRST HALF OF NEXT WEEK
STILL HAS A FAIRLY WIDE RANGE. THE LOWER END OF GUIDANCE SHOWS
HIGHS STAYING IN THE MID TO UPPER 90S, WHILE THE UPPER RANGE SHOWS
HIGHS BACK TO NEAR 105 DEGREES. THE CURRENT NBM FORECAST IS MOSTLY
IN THE MIDDLE WITH HIGHS RANGING FROM 99-102 DEGREES FOR NEXT
MONDAY-WEDNESDAY. EITHER WAY, THE FORECAST CALLS FOR DRY
CONDITIONS TO PREVAIL THROUGH THE FIRST HALF OF NEXT WEEK.
AVIATION
UPDATED AT 0520Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR AVIATION CONCERNS ARE ANTICIPATED THROUGH THE FORECAST
PERIOD. WINDS WILL FOLLOW DIURNAL TENDENCIES WITH LIGHT EASTERLY
FLOW EXPECTED AT KIWA AND KPHX OVERNIGHT. WINDS WILL BE SLOW TO
TRANSITION TO WESTERLY ON THURSDAY WITH ANOTHER PROLONGED PERIOD
OF SOUTHERLY CROSS-RUNWAY WINDS AT KPHX BEGINNING AROUND 16Z.
WINDS WILL FINALLY VEER OUT OF THE WSW BY THE LATE AFTERNOON WITH
GUSTS RANGING FROM THE UPPER TEENS TO AROUND 20 KTS AT ALL AREA
TERMINALS. EXPECT ANOTHER ROUND OF CU ON THURSDAY AFTERNOON WITH
BASES 8-10 KFT.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION CONCERNS UNDER MOSTLY CLEAR SKIES ARE EXPECTED THROUGH
THE FORECAST PERIOD. THE PRIMARY WIND DIRECTION WILL BE W AT KIPL
AND S-SW AT KBLH. SPEEDS SHOULD REMAIN AOB 10 KTS THROUGH THURSDAY
AFTERNOON.
FIRE WEATHER
THE WEATHER PATTERN OVER THE NEXT SEVERAL DAYS WILL CONTINUE TO
BRING OVERALL DRY CONDITIONS WITH TEMPERATURES DROPPING TO
SLIGHTLY BELOW NORMAL THURSDAY INTO FRIDAY. A WEATHER SYSTEM
SLOWLY MOVING INTO THE REGION FROM THE NORTHWEST WILL RESULT IN
OCCASIONALLY BREEZY CONDITIONS WITH PEAK WINDS LIKELY TODAY AS
GUSTS REACH TO AROUND 25 MPH AT TIMES IN THE AFTERNOON. THERE WILL
BE SOME RAIN CHANCES ACROSS THE EASTERN ARIZONA HIGH TERRAIN TODAY
AND THURSDAY WITH WETTING RAIN CHANCES OF 10-20% ACROSS EASTERN
GILA COUNTY. MINRHS OVER THE NEXT FEW DAYS ARE LIKELY TO RANGE
FROM 10-15% ACROSS THE WESTERN DISTRICTS TO 15-25% ACROSS THE
EASTERN DISTRICTS. BY FRIDAY AND INTO THE WEEKEND, EVEN DRIER
CONDITIONS ARE EXPECTED WITH WINDS RETURNING TO A TYPICAL LIGHT
AND DIURNAL PATTERN.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...WIND ADVISORY UNTIL 2 AM PDT THURSDAY FOR CAZ562.
SHORT TERM...WHITTOCK
LONG TERM...KUHLMAN
AVIATION...SALERNO
FIRE WEATHER...KUHLMAN
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