959
FXUS65 KPSR 120524
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1024 PM MST THU SEP 11 2025
UPDATE
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
- TEMPERATURES GRADUALLY COOL, WITH NEAR TO BELOW-NORMAL READINGS
EXPECTED THROUGH THE WEEKEND.
- BREEZY CONDITIONS WILL DEVELOP ONCE AGAIN THIS AFTERNOON FOR
PARTS OF THE REGION WITH PEAK GUSTS AROUND 25-30 MPH.
- OUTSIDE OF SOME ISOLATED TO SCATTERED RAIN CHANCES FOR EASTERN
ARIZONA THROUGH THE END OF THE WORKWEEK, THE MAJORITY OF OUR
FORECAST AREA SHOULD REMAIN DRY OVER THE NEXT SEVERAL DAYS.
SHORT TERM /TODAY THROUGH FRIDAY/
THE LATEST WATER VAPOR SATELLITE IMAGERY AS WELL AS STREAMLINE
ANALYSIS DEPICT AN UPPER-LEVEL TROUGH SITUATED NEAR EASTERN OREGON
WITH THE SUBTROPICAL HIGH SITUATED OVER THE SOUTHERN PLAINS. THIS
PATTERN CONFIGURATION HAS RESULTED IN SOUTHWESTERLY FLOW ALOFT
ACROSS MUCH OF THE DESERT SOUTHWEST. HOWEVER, AT LOW-LEVELS AT
AROUND 700 MB, THE FLOW IS OUT OF THE SOUTH AND THUS LOW-LEVEL
MOISTURE CONTINUES TO BE ADVECTED NORTHWARD THROUGH CENTRAL AND
SOUTHERN AZ WITH PWATS ABOVE 1.0". EVEN THOUGH THE MOISTURE
CONTENT IS MARGINAL, ENOUGH MOISTURE WILL BE PRESENT TO SPARK THE
DEVELOPMENT OF SHOWER AND THUNDERSTORM ACTIVITY THROUGH EARLY
THIS EVENING, WITH THE FOCUS REMAINING ACROSS THE EASTERN THIRD OF
AZ, PARTICULARLY ACROSS SOUTHERN GILA AND EASTERN PINAL COUNTIES.
THE MAIN IMPACT WITH ANY OF THESE THUNDERSTORMS WILL BE SOME
STRONG GUSTY WINDS, WHICH CAN SEND AN OUTFLOW WESTWARD INTO THE
LOWER ELEVATIONS OF SOUTH-CENTRAL AZ, WITH THE LATEST HREF
MEMBERSHIP INDICATING A 30-50% CHANCE OF GUSTS EXCEEDING 35 MPH.
ENOUGH LOW-LEVEL MOISTURE WILL REMAIN PRESENT FOR FRIDAY TO RESULT
IN AROUND ROUND OF AFTERNOON AND EARLY EVENING THUNDERSTORMS
ACROSS THE EASTERN THIRD OF AZ BEFORE CONDITIONS DRY OUT
COMPLETELY OVER THE WEEKEND.
ASIDE FROM THE THUNDERSTORM ACTIVITY ACROSS THE EASTERN THIRD OF AZ
THROUGH FRIDAY, THE REST OF THE AREA SHOULD REMAIN DRY WITH SOME
AFTERNOON AND EARLY EVENING BREEZINESS LINGERING WITH GUSTS
UPWARDS OF 25-30 MPH AT TIMES. WITH THE TROUGH MOVING THROUGH THE
WESTERN CONUS, TEMPERATURES DURING THE NEXT COUPLE OF DAYS WILL
CONTINUE TO REMAIN NEAR TO SLIGHTLY BELOW NORMAL WITH AFTERNOON
HIGHS IN THE MID TO UPPER 90S ACROSS THE WESTERN DESERTS TO
AROUND 100 DEGREES ACROSS THE PHOENIX AREA WITH THE OVERALL
HEATRISK LEVELS REMAINING IN THE MINOR CATEGORY.
LONG TERM /SATURDAY THROUGH THURSDAY/
HEADING INTO THE WEEKEND, MODELS HAVE THE PACIFIC TROUGH CONTINUING
ITS EASTWARD PROGRESSION, CLEARING ARIZONA BY LATE SATURDAY/EARLY
SUNDAY. AS IT MIGRATES TOWARDS THE GREAT PLAINS, UNSEASONABLY DRY
AIR WILL CUT OFF ANY FURTHER RAIN CHANCES FOR OUR AREA AS PWATS
FALL TO ONLY 50% OF NORMAL FOR THIS TIME OF YEAR. THE GOOD NEWS
IS, EVEN AS WE FULLY DRY OUT, TEMPERATURES WILL NOT REBOUND AS
QUICKLY AS WE HAVE SEEN THIS SUMMER AS FLOW ALOFT BECOMES MORE
ZONAL RATHER THAN RAPIDLY SHIFTING BACK TO INCREASING HIGH
PRESSURE. TEMPERATURES THIS WEEKEND WILL CONTINUE THEIR END-OF-
WEEK TREND, WITH HIGHS HOVERING NEAR TO SLIGHTLY BELOW NORMAL.
THE OVERALL PICTURE BECOMES A LITTLE LESS CLEAR AS WE APPROACH NEXT
WEEK. A LOT OF THIS UNCERTAINTY STEMS FROM WHAT COULD BECOME THE
NEXT TROPICAL CYCLONE OVER THE EASTERN PACIFIC. AS OF NOW, MODELS
GENERALLY FAVOR THE TRACK OF THIS SYSTEM REMAINING OFF THE WESTERN
COAST OF THE BAJA PENINSULA BEFORE EVENTUALLY FALLING APART.
HOWEVER, IT APPEARS THAT SOME MODELS WANT TO BRING SOME REMNANT
TROPICAL MOISTURE TOWARD OUR FORECAST AREA, WHICH COULD RESULT IN
CONSIDERABLE CLOUD COVER AND EVEN RAIN CHANCES. SUBTLE SHIFTS IN THE
FORECAST COULD YIELD A VASTLY DIFFERENT FOREAST SOLUTIONS FOR
THIS TIMEFRAME, SO HOW THIS POTENTIAL SYSTEM EVOLVES WILL BE
SOMETHING TO MONITOR IN THE COMING DAYS. AS OF NOW, GLOBAL MODELS
FAVOR THE RETURN OF BROAD RIDGING BY NEXT WEEK, WHICH WOULD
TRANSLATE TO INCREASING TEMPERATURES BACK TO ABOVE-NORMAL LEVELS,
BUT THERE IS A NOTICEABLE SPREAD IN THE INTERQUARTILE TEMP
FORECAST POTENTIALLY REFLECTING MODEL UNCERTAINTY RELATING TO THE
AFOREMENTIONED TROPICAL SYSTEM.
AVIATION
UPDATED AT 0525Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO AVIATION CONCERNS EXPECTED THROUGH THE TAF PERIOD. EXPECT
PERIODS OF LIGHT AND VARIABLE WINDS ALONG WITH THE TYPICAL DIURNAL
SHIFT OUT OF THE EAST THROUGH TONIGHT INTO LATE TOMORROW MORNING
WHERE WINDS WILL SHIFT OUT OF THE WEST WITH LATE MORNING THROUGH
AFTERNOON INTO EARLY TOMORROW EVENING GUSTS UP TO 20-25KTS. SKIES
CONTINUE TO CLEAR OUT AND WILL BE MOSTLY CLEAR TOMORROW, KIWA
BEING THE LONE TERMINAL WITH A SCT LAYER AT 11 KFT. GUIDANCE DOES
SHOW SHOWERS AND THUNDERSTORMS DEVELOPING ACROSS THE HIGHER
TERRAIN EAST OF PHOENIX FRIDAY AFTERNOON. HOWEVER, UNLIKE THURSDAY
MOST OF THE FORMATION IS EXPECTED TO DEVELOP EVEN FURTHER EAST
WITH ANY ASSOCIATED OUTFLOWS NOT EXPECTED TO IMPACT THE VALLEY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION CONCERNS UNDER CLEAR SKIES ARE EXPECTED THROUGH THE
FORECAST PERIOD. WESTERLY WINDS WILL PREVAIL WITH A PERIOD OF
LIGHT AND VARIABLE WINDS WITH GENERAL FLOW OUT OF THE WNW FOR KBLH
KBLH. SUSTAINED WIND SPEEDS WILL MOSTLY REMAIN LESS THAN 10 KTS
AT BOTH TERMINALS.
FIRE WEATHER
NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES WILL BE COMMON ACROSS
THE REGION THROUGH THIS WEEKEND THANKS TO AN AREA OF LOW PRESSURE
PASSING TO OUR NORTH. OUTSIDE OF SOME BREEZY CONDITIONS THIS
AFTERNOON WITH PEAK GUSTS AROUND 25-30 MPH, WINDS OVER THE NEXT
SEVERAL DAYS WILL FAVOR FAMILIAR DIURNAL TRENDS. MOST OF OUR
FORECAST AREA WILL REMAIN DRY, BUT SOME SLIGHT CHANCES OF WETTING
RAINS DO EXIST FOR THE HIGH TERRAIN OF GILA COUNTY BOTH THIS
AFTERNOON AND FRIDAY. 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 THIS WEEKEND, EVEN DRIER CONDITIONS ARE
EXPECTED.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...LOJERO
LONG TERM...RW
AVIATION...95
FIRE WEATHER...RW/LOJERO
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