860
FXUS65 KPSR 112325
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
425 PM MST THU JUN 11 2026
UPDATE
UPDATED AVIATION
KEY MESSAGES
- FAIRLY STABLE TEMPERATURES AROUND 4 TO 8 DEGREES ABOVE DAILY
NORMALS WILL RESULT IN WIDESPREAD MODERATE HEAT RISK, WITH ISOLATED
POCKETS OF MAJOR HEAT RISK THROUGH THE MIDDLE OF NEXT WEEK.
- AN INCREASE IN MOISTURE BY THE END OF THE WEEK INTO THE WEEKEND
WILL LEAD TO SLIGHT CHANCES FOR SHOWERS AND STORMS, WITH BETTER
CHANCES CURRENTLY FOCUSED DURING MORNING AND OVERNIGHT PERIODS.
- OVERNIGHT LOW TEMPERATURES WILL BE NOTICEABLY WARMER AS A RESULT
OF INCREASED HUMIDITY, WITH THE TYPICALLY WARMER LOWER DESERT
LOCALES STRUGGLING TO COOL BELOW 80 DEGREES BY THE WEEKEND.
SHORT TERM /TODAY THROUGH SATURDAY/
CURRENT RAP ANALYSIS AND SATELLITE IMAGERY SHOWS BROAD RIDGING OVER
THE EASTERN PACIFIC AND AN UPPER LEVEL LOW OFF THE WESTERN COASTLINE
OF THE BAJA PENINSULA. WITH THIS UPPER LEVEL LOW A SWATH OF MOISTURE
CAN ALREADY BE SEEN PUSHING INTO THE DESERT SW FROM THE GULF OF
CALIFORNIA. MODELS REMAIN IN GOOD AGREEMENT THAT THIS UPPER LEVEL
LOW WILL CONTINUE TO TRACK NORTHEASTWARDS ALONG THE BAJA PENINSULA
CAUSING PWATS TO CLIMB TO 1.0-1.5" OR NEAR 200-250% OF NORMAL,
THROUGHOUT THE WEEKEND.
THE FIRST CHANCE OF ACTIVITY WILL BE FRIDAY MORNING IN SOUTHEASTERN
CA AND SOUTHWESTERN AZ. DURING THIS TIME, IN ADDITION TO THE
PLENTIFUL MOISTURE, DETERMINISTIC RUNS SIGNAL FOR DECENT POCKET OF
CYCLONIC VORTICITY RIDING UP ALONG THE COLORADO RIVER VALLEY FRIDAY,
WITH THE HREF SHOWING MUCAPES BETWEEN 250-500 J/KG. THESE CONDITIONS
WILL BE FAVORABLE FOR THE DEVELOPMENT IN ISOLATED SHOWERS STARTING
EARLY FRIDAY MORNING BEFORE DISSIPATING HEADING INTO THE AFTERNOON
HOURS. BY SATURDAY MUCH OF THE LIFTING MECHANISMS IN PLACE FROM
FRIDAY WILL HAVE DWINDLED, HOWEVER MIXING RATIOS OVER SOUTHCENTRAL
AZ AND THE PHOENIX METRO WILL BEGIN TO INCREASE FROM 7-8 G/KG TO
BETWEEN 8-10 G/KG BY SATURDAY AFTERNOON/EVENING, AND MINIMAL MUCAPE
(~100-250 J/KG) WILL REMAIN OVER THE REGION. THIS CAN BE ENOUGH TO
FACILITATE THE DEVELOPMENT OF ISOLATED SHOWERS IN THE LOWER DESERTS,
HOWEVER MODELS HINT AT THE BULK OF THE ACTIVITY REMAINING EAST OF
THE PHOENIX METRO IN THE EASTERN HIGHER TERRAIN AREAS WHERE POPS ARE
CURRENTLY ONLY AROUND 10-15%.
TEMPERATURES THROUGH THE REMAINDER OF THE WORKWEEK AND INTO THE
BEGINNING OF THE WEEKEND WILL REMAIN FAIRLY STABLE BETWEEN 104F-110F
ACROSS THE LOWER DESERTS. THIS IS A RESULT IN H5 HEIGHTS REMAINING
FAIRLY STABLE AS WELL, WITH HEIGHTS BETWEEN 588-591 DAM PERSISTING
OVER THE DESERT SW. ONE NOTABLE DIFFERENCE WILL BE WARMER OVERNIGHT
LOWS, THANKS TO THE INCREASE IN MOISTURE AND SOME INFLUENCE FROM
CLOUD COVER FRIDAY-SATURDAY LEADING TO LOWS IN THE UPPER 70S TO MID
80S. ALL THAT BEING SAID, WIDESPREAD MODERATE TO LOCALIZED AREAS OF
MAJOR HEATRISK WILL IN PLACE THROUGH THE WEEKEND AND INTO NEXT WEEK.
SO ENSURE TO STAY HYDRATED AND FOLLOW PROPER HEAT SAFETY PROTOCOL.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
A FEW CHANGES ARE NOTED IN THE LATEST ENSEMBLES AND GLOBAL MODEL
RUNS: MEASURES OF MOISTURE OVER THE FORECAST AREA (E.G., PWATS,
MIXING RATIOS) ARE PEAKING AT SLIGHTLY LOWER VALUES, HOWEVER,
MOISTURE IS NOT EFFECTIVELY SCOURED OUT AND WILL LIKELY LINGER INTO
EARLY NEXT WEEK, PROVIDING FURTHER CHANCES FOR AFTERNOON AZ HIGH
TERRAIN THUNDERSTORMS. THE LIMITED INSTABILITY WITH LARGE T/TD
SPREADS AND DRY SUB-CLOUD LAYER WILL FAVOR DRY LIGHTNING AND GUSTY
OUTFLOW WINDS VERSUS HEAVY RAINFALL, AS IS TYPICAL WITH CONVECTIVE
ACTIVITY IN JUNE. THESE CHANGES COME AS ENSEMBLES NOW SHOW THE
CYCLONICALLY CURVED POLAR JET, AND ANY ATTENDANT SHORTWAVE TROUGHS
ROTATING THROUGH THE BASE OF THE MEAN TROUGH OVER THE NORTH-CENTRAL
CONUS, REMAINING FURTHER EAST OF THE REGION. WHILE FLOW ALOFT WILL
TURN OUT OF A DRIER WESTERLY OR NORTHWESTERLY DIRECTION SUNDAY, THE
MORE DISTANT INFLUENCE OF POLAR JET WILL MEAN THAT THE FLOW STAYS
FAIRLY WEAK OVER REGION, MUCH LESS EFFECTIVE AT SCOURING OUT
LINGERING MOISTURE. POSITIVE MIDLEVEL HEIGHT ANOMALIES REMAINING
FAIRLY STAGNANT THROUGH THE MIDDLE OF THE WEEK WILL ALLOW FOR STEADY
TEMPERATURES IN A 4 TO 8 DEGREE ABOVE NORMAL RANGE. TEMPERATURES
WILL BE SLIGHTLY HIGHER IN THE WESTERN DESERTS, BUT REGARDLESS,
LOWER DESERT HIGHS WILL PEAK NEAR OR JUST ABOVE 110F FOR THE
TYPICALLY HOTTER SPOTS.
AVIATION
UPDATED AT 2325Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
WIND FORECASTS WILL BE THE PRIMARY WEATHER ISSUE THROUGH FRIDAY
EVENING UNDER THICKENING MID/HIGH CLOUD DECKS. CONFIDENCE IS GOOD
THAT W/SW WINDS WILL PERSIST LONGER INTO THE OVERNIGHT THAN PREVIOUS
DAYS. MODELING SUGGESTS PERIODS OF STRONGER GUSTS ~20KT WILL BE
POSSIBLE THROUGH THE EVENING, THOUGH CONFIDENCE ON COVERAGE AND
DURATION IS LOW. SOME AREAS MAY NEVER TRULY OBTAIN AN EASTERLY
FETCH FRIDAY MORNING, BUT RATHER BECOMING VARIABLE BEFORE RAPIDLY
SWITCHING BACK TO A WESTERLY COMPONENT. MORE WIDESPREAD AND
PRONOUNCED GUSTINESS IS LIKELY FRIDAY AFTERNOON/EVENING.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
THE PROSPECT FOR A FEW SHRA FRIDAY MORNING WILL BE THE MAIN WEATHER
ISSUE UNDER MID/HIGH CIGS. CONFIDENCE IS GOOD THAT S/SE WINDS WILL
SWING W/SW BRIEFLY MID/LATE EVENING BEFORE REVERTING TO S/SE
OVERNIGHT. HAVE NOT INCLUDED A VCSH MENTION IN THIS TAF PACKAGE,
HOWEVER A FEW SHRA WILL BE POSSIBLE AROUND AND JUST AFTER SUNRISE
WITH PERIODS OF VIRGA LIKELY THROUGHOUT THE DAY.
FIRE WEATHER
TEMPERATURES 3-6 DEGREES ABOVE NORMAL WILL PREVAIL WITH LOWER DESERT
HIGHS NEAR 110F IN SOME OF THE HOTTER SPOTS, ESPECIALLY BY THE
WEEKEND. DRY CONDITIONS WILL CONTINUE TODAY WITH RELATIVE HUMIDITY
BOTTOMING OUT AROUND 8-15%. LOW LEVEL MOISTURE WILL CONTINUE TO
IMPROVE IMPROVE THROUGH THIS WEEKEND WITH MINIMUM HUMIDITY LARGELY
ABOVE 15% AND OVERNIGHT RECOVERIES GENERALLY IMPROVING FROM POOR TO
FAIR. WITH THE INCREASING MOISTURE WILL ALSO COME INCREASING CHANCES
FOR ISOLATED SHOWER/T-STORM ACTIVITY STARTING FRIDAY MORNING ALONG
THE COLORADO RIVER VALLEY AND THEN AGAIN ACROSS THE AZ HIGH TERRAIN
OVER THE WEEKEND, WITH GUSTY OUTFLOW WINDS AND DRY LIGHTNING
POTENTIALLY LEADING TO NATURAL FIRE STARTS BEING THE MAIN HAZARDS.
THE OVERALL WIND PATTERN WILL REMAIN DIURNAL WITH SPEEDS AT OR BELOW
15 MPH AND LIMITED AFTERNOON UPSLOPE GUSTINESS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...RYAN
LONG TERM...WHITTOCK
AVIATION...18
FIRE WEATHER...SALERNO/RYAN
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