319
FXUS65 KPSR 151737
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1037 AM MST FRI AUG 15 2025
UPDATE
UPDATED 18Z AVIATION DISCUSSION.
KEY MESSAGES
- ANOTHER ROUND OF SCATTERED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE TODAY AND TONIGHT WITH GUSTY WINDS, HEAVY RAIN,
BLOWING DUST, AND LIGHTNING THE MAIN THREATS.
- RAINFALL CHANCES DECREASE SUBSTANTIALLY OVER THE WEEKEND WITH
STORMS PRIMARILY RELEGATED TO HIGHER TERRAIN AREAS OF CENTRAL
AND EASTERN ARIZONA.
- TEMPERATURES WILL DROP INTO A SEASONAL NORMAL RANGE THROUGH THE
WEEKEND BEFORE READINGS REBOUND BACK ABOVE NORMAL BY THE MIDDLE
OF NEXT WEEK.
SHORT TERM /TODAY THROUGH SATURDAY/
SHOWERS AND THUNDERSTORMS HAVE BEEN ONGOING FOR SEVERAL HOURS
ACROSS SOUTHCENTRAL AZ, BRINGING POCKETS OF HEAVY RAINFALL AND
LOCALIZED FLASH FLOODING. THIS IS ALL DUE TO A LEADING SHORTWAVE
TROUGH WHICH IS ROTATING THROUGH THE REGION AHEAD OF A MAIN UPPER-
LVL LOW LOCATED OVER SOCAL. RAINFALL AMOUNTS HAVE RANGED FROM
AROUND 0.25-0.50" ACROSS THE PHOENIX METRO OVERNIGHT WITH ISOLATED
SPOTS RECEIVING OVER AN 1.00". STORM ACTIVITY WILL GRADUALLY
DIMINISH BY SUNRISE AND SHIFT OVER THE FOOTHILLS AND HIGHER
TERRAIN NE OF PHOENIX THIS MORNING. DUE TO ALL THE RAINFALL
ACTIVITY AND INCREASING MOISTURE TEMPERATURES HAVE FALLEN INTO
THE 70S AND LOWER 80S ACROSS THE PHOENIX METRO AND WE WILL FINALLY
SEE AN AFTERNOON WITH NEAR NORMAL TEMPERATURES WHICH AS BEEN
ELUDING US SINCE LATE JULY.
HEADING INTO THIS AFTERNOON AND EVENING, THE OVERALL SYNOPTIC
PATTERN REMAINS FAVORABLE FOR ADDITIONAL CONVECTIVE DEVELOPMENT
ACROSS SOUTHEASTERN AND SOUTHCENTRAL AZ. THE AFOREMENTIONED UPPER
LOW WILL LIFT INTO THE GREAT BASIN REGION THIS AFTERNOON,
PROMOTING AMPLE LARGE SCALE LIFT AS ADDITIONAL SHORTWAVES ROTATE
THROUGH OUR FORECAST AREA. LATEST FORECAST RAP 13 AND GFS BUFR
SOUNDINGS INDICATE THAT THE REGION WILL REMAIN LARGELY UNCAPPED
WITH LITTLE TO NO CIN AND BOUNTIFUL MOISTURE IN PLACE AS PWATS
HOVER AROUND 1.5"- 1.6". SUFFICIENT INSTABILITY WITH ML CAPE AND
DCAPE VALUES UP TO 1500 J/KG WILL PROVIDE A THREAT FOR STRONG TO
MARGINALLY SEVERE STORMS CAPABLE OF PRODUCING ROBUST DOWNDRAFTS
AND STRONG OUTFLOW WINDS UP TO 50-60 MPH. NBM POPS STILL REMAIN
AROUND 30-60% THIS AFTERNOON AND EVENING ACROSS THE LOWER DESERTS
AND FOOTHILLS OF MARICOPA AND PINAL COUNTIES. CHANCES WILL SLOWLY
DIMINISH TONIGHT, BUT THERE WILL STILL BE AT LEAST A 20% CHANCE
FOR RESIDUAL SHOWERS AND THUNDERSTORMS INTO EARLY SATURDAY
MORNING.
ON SATURDAY, THE PACIFIC TROUGH TO OUR NW WILL PROGRESS FARTHER
INLAND, WHICH IS EXPECTED TO USHER IN DRIER AIR INTO OUR AREA FROM
WEST TO EAST. THIS DRY AIR WILL FIRST MOVE IN ALOFT EARLY SATURDAY
AND THEN MIX DOWN INTO THE BOUNDARY LAYER SATURDAY AFTERNOON. THE
LINGERING BOUNDARY LAYER MOISTURE SHOULD BE ENOUGH TO SPARK OFF SOME
AFTERNOON CONVECTION OVER HIGHER TERRAIN AREAS (20-40% POPS), BUT
FOR THE SOUTH-CENTRAL ARIZONA LOWER DESERTS CHANCES WILL BE AT MOST
10-20%. DUE TO THE PRESENCE OF THE TROUGH BRINGING NEGATIVE HGHT
ANOMALIES TO THE DESERT SOUTHWEST, TEMPERATURES ARE EXPECTED TO
BE A FEW DEGREES BELOW AVERAGE WITH HIGHS MAINLY RANGING FROM
95-103 ACROSS THE LOWER DESERTS.
LONG TERM /SUNDAY THROUGH THURSDAY/
THE INFLUENCE OF THE PACIFIC TROUGH WILL HELP TO KEEP TEMPERATURES
NEAR NORMAL THROUGH THE REMAINDER OF THIS WEEKEND AND INTO EARLY
NEXT WEEK WITH HIGHS IN A NEAR NORMAL RANGE BETWEEN 102-105
DEGREES ACROSS THE LOWER DESERTS. WE WILL ALSO SEE NOTICEABLY
COOLER OVERNIGHT TEMPERATURES AS LOWS FALL BACK INTO THE 70S
ACROSS THE WESTERN DESERTS TO AROUND 80 OR THE LOWER 80S IN THE
PHOENIX AREA FOR SUNDAY AND MONDAY MORNINGS.
ENJOY THE MILD WEATHER WHILE YOU CAN BECAUSE THE PATTERN WILL BEGIN
TO SHIFT AGAIN BEGINNING EARLY NEXT WEEK AS THE SUBTROPICAL HIGHS
SHIFTS WESTWARD INTO OUR REGION BY NEXT TUESDAY. ENSEMBLE GUIDANCE
SHOWS THE RIDGE CENTER STRENGTHENING DURING THIS TIME BEFORE
REACHING ITS PEAK AT SOME POINT MID TO LATE NEXT WEEK. THIS WILL
LIKELY BRING H5 HEIGHTS OF 595-597DM BACK INTO OUR AREA BY THE
MIDDLE OF NEXT WEEK RESULTING IN HIGHS WARMING BACK TO AROUND 110
DEGREES BY NEXT TUESDAY. OVERNIGHT LOWS WILL ALSO BEGIN TO WARM, BUT
WITH LOW LEVEL MOISTURE REMAINING ON THE LOWER SIDE READINGS SHOULD
STAY NEAR OR JUST ABOVE NORMAL INTO MID WEEK. THE INEVITABLE
STRENGTH OF THE RIDGE WILL LEAD TO AREAS OF MAJOR HEATRISK AGAIN
BEGINNING AS EARLY AS WEDNESDAY AND PERSISTING THROUGH THE END OF
THE WEEK. ALTHOUGH STILL FAIRLY UNCERTAIN, MODELS DO SHOW SOME
MOISTURE BEGINNING TO CREEP BACK INTO THE REGION LATE NEXT WEEK
INTO THE FOLLOWING WEEKEND WHICH WILL PROVIDE AT LEAST A SHOT OF
SOME ISOLATED THUNDERSTORM ACTIVITY.
AVIATION
UPDATED AT 1730Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE MAIN AVIATION WEATHER CONCERN HEADING INTO EARLY THIS EVENING
WILL BE THE POTENTIAL FOR ANOTHER ROUND OF THUNDERSTORM ACTIVITY
IN THE VICINITY, RESULTING IN GUSTY AND ERRATIC WINDS AND
LOCALIZED HEAVY RAINFALL. IN THE MEANTIME, THROUGH THE MID-
AFTERNOON HOURS, WEATHER CONDITIONS SHOULD REMAIN RELATIVELY
TRANQUIL WITH THE OVERALL WIND PATTERN EXHIBITING THE FAMILIAR
DIURNAL TENDENCIES WITH A FEW HOURS OF SOUTHERLY CROSS-WINDS
LIKELY DURING THE DIURNAL TRANSITION. THEREAFTER, THE CHANCES OF
THUNDERSTORM ACTIVITY INCREASES. ACTIVITY WILL LIKELY DEVELOP
INITIALLY SOUTH OF PHOENIX, WITH AN OUTFLOW BOUNDARY LIKELY TO
INITIATE ADDITIONAL ACTIVITY OVER THE PHOENIX AREA. THE MOST
LIKELY TIMING FOR IMPACTS IS BETWEEN 01-04Z. THERE IS A 30-50%
CHANCE OF GUSTS EXCEEDING 30 KTS. CONDITIONS SHOULD IMPROVE BY THE
MID TO LATE EVENING HOURS WITH WINDS SHIFTING OUT THE EAST. FEW-
SCT MID TO HIGH-LEVEL CLOUDS WILL BE COMMON THROUGH THIS AFTERNOON
BEFORE BECOMING SCT-BKN BY THE EARLY EVENING HOURS AS THE
CONVECTIVE COVERAGE INCREASES.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION WEATHER CONCERNS UNDER CLEAR SKIES CAN BE
EXPECTED THROUGHOUT THE TAF PERIOD. AT KIPL, WINDS WILL BE OUT OF
THE SOUTHEAST THROUGH THIS AFTERNOON BEFORE SHIFTING OUT THE WEST
TEMPORARILY EARLY THIS EVENING. AT KBLH, WINDS WILL GENERALLY BE
OUT OF THE SOUTH WITH GUSTS UP TO 25 KTS COMMON DURING THE
AFTERNOON AND EARLY EVENING HOURS.
FIRE WEATHER
WIDESPREAD WETTING RAINFALL HAS BEEN OBSERVED ACROSS THE EASTERN
DISTRICTS OVERNIGHT WHICH SHOULD IMPROVE OVERALL FUEL MOISTURE.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THIS
AFTERNOON AND EVENING ACROSS SOUTHCENTRAL AZ WITH WITH MODERATE
CHANCES OF WETTING RAINFALL, PARTICULARLY OVER HIGHER TERRAIN OF
GILA COUNTY. WINDS WILL CONTINUE TO FOLLOW DIURNAL PATTERNS EXCEPT
IN THE VICINITY OF ANY THUNDERSTORMS WHERE ABRUPT WIND SHIFTS WITH
GUSTY OUTFLOWS WILL BE COMMON. TEMPERATURES WILL COOL CLOSER TO
THE SEASONAL NORMAL TODAY THROUGH THIS WEEKEND. AFTERNOON HUMIDITY
LEVELS SHOULD IMPROVE CLOSER TO A 20-30% RANGE IN EASTERN
DISTRICTS, BUT REMAIN 10-20% IN WESTERN AREAS. OVERNIGHT RECOVERY
WILL VARY WIDELY ACROSS THE AREA FROM 30% TO 80%. DRIER AIR WILL
USHER BACK INTO THE AREA OVER THE WEEKEND MOSTLY ENDING RAIN
CHANCES EXCEPT FOR FAR EASTERN ARIZONA. MINRHS WILL EVENTUALLY
LOWER TO CLOSER TO 10- 15% BY NEXT MONDAY.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...SALERNO
LONG TERM...SALERNO
AVIATION...LOJERO
FIRE WEATHER...SALERNO
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