881
FXUS65 KPSR 070500
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1000 PM MST WED MAY 6 2026
UPDATE
UPDATED AVIATION DISCUSSION
KEY MESSAGES
- A PRONOUNCED WARMING AND DRYING TREND WILL OCCUR OVER THE NEXT
SEVERAL DAYS PUSHING TEMPERATURES ABOVE NORMAL STARTING
THURSDAY.
- HOT TEMPERATURES WILL DEVELOP OVER THE REGION BY THE WEEKEND
WITH LOWER DESERT HIGHS TOPPING 100 DEGREES AS EARLY AS FRIDAY
BEFORE PEAKING BETWEEN 105 AND 110 DEGREES EARLY NEXT WEEK.
SHORT TERM /TODAY THROUGH THURSDAY/
A SW-NE ORIENTED SHORTWAVE TROUGH IS APPARENT IN MIDLEVEL WATER
VAPOR IMAGERY AND 500 MB RAP ANALYSIS, STRETCHING FROM JUST OFF
THE NORTHERN BAJA AT ITS BASE UP THROUGH THE FOUR CORNERS/NORTHERN
NM. GLOBAL GUIDANCE HAS BEEN IN GOOD AGREEMENT ON THE EVOLUTION
OF THIS TROUGH, WITH THE BULK OF THE ENERGY PROGRESSING EASTWARD
AND JOINING LONGWAVE TROUGHING OVER CENTRAL/NORTHEASTERN CONUS,
WHILE A RELATIVELY STRONG VORTICITY CENTER CLOSES OFF NEAR THE
BASE, FORMING A CUTOFF LOW OVER THE NORTHERN BAJA OR GULF OF
CALIFORNIA. THIS CUTOFF LOW WILL THEN MEANDER EASTWARD OVER SONORA
THROUGH THURSDAY, STAYING WELL SOUTH OF THE AREA AND HAVING
LITTLE SENSIBLE WEATHER IMPACT.
THE MAIN STORY THROUGH THE END OF THE WORK WEEK WILL BE THE
BUILDING INFLUENCE OF A RIDGE EDGING EASTWARD OVER THE WEST COAST
AND POSITIVE MIDLEVEL HEIGHT ANOMALIES ENTERING THE AREA FROM THE
WEST/NORTHWEST, WHICH WILL HELP RAPIDLY WARM THERMAL PROFILES
ACROSS THE REGION. NAEFS MEAN 850 MB TEMPERATURES THAT AS OF EARLY
THIS MORNING WERE NEAR THE 10TH PERCENTILE OF CLIMATOLOGY FOR
THIS TIME OF YEAR (APPROXIMATELY 10C) WILL QUICKLY WARM AS
SHORTWAVE ENERGY DEPARTS AND THE CUTOFF SOUTH OF THE AREA WEAKENS
AND PROGRESSES EAST OF SONORA LATE THURSDAY. IN FACT, ENSEMBLE
MEAN 850 MB TEMPERATURES APPROACH THE 85TH-90TH PERCENTILE OF
CLIMATOLOGY (21C-23C), ESPECIALLY OVER THE WESTERN CWA, BY
THURSDAY AFTERNOON. THIS WILL SUPPORT LOWER DESERT HIGHS WARMING
ABOVE NORMAL BY THURSDAY, IN THE UPPER 90S ACROSS THE LOWER CO
RIVER VALLEY AND SOUTHEAST CALIFORNIA TO AROUND 91F-96F ACROSS THE
GREATER PHOENIX AREA.
LONG TERM /FRIDAY THROUGH TUESDAY/
A NOTICEABLE SHIFT IN THE WEATHER PATTERN LATE THIS WEEK AND LASTING
THROUGH AT LEAST THE FIRST PART OF NEXT WEEK WILL LEAD TO ANY
WEATHER SYSTEMS TRACKING ACROSS SOUTHERN CANADA INTO THE NORTH-
CENTRAL AND NORTHEASTERN U.S. UPPER LEVEL RIDGING WILL ALSO SLOWLY
TAKE OVER ACROSS MUCH OF THE WESTERN U.S. AND EVENTUALLY INTO THE
SOUTHERN PLAINS BY EARLY NEXT WEEK. THE FIRST RIDGE THAT WILL MOVE
INTO OUR REGION LATE THIS WEEK IS EXPECTED TO WEAKEN SOMEWHAT, BUT
ANOTHER EVEN STRONGER RIDGE IS FAVORED TO BUILD IN FROM THE WEST
OVER THE WEEKEND AND LAST THROUGH AT LEAST THE FIRST PART OF NEXT
WEEK. H5 HEIGHTS ARE SEEN RISING TO BETWEEN 582-585DM THIS WEEKEND
BEFORE LIKELY PEAKING BETWEEN 588-591DM NEXT MONDAY. FORECAST
UNCERTAINTY INCREASES A BIT GOING INTO THE MIDDLE OF NEXT WEEK AS
THERE ARE SOME DISCREPANCIES WITH A WEAK CUT-OFF LOW THAT MAY
DEVELOP WEST OF BAJA. HOWEVER, FOR NOW THIS FEATURE MAY END UP BEING
TOO WEAK TO HAVE MUCH INFLUENCE OVER OUR REGION LATER NEXT WEEK.
FORECAST TEMPERATURES CONTINUE TO RISE OVER THE WEEKEND INTO EARLY
NEXT WEEK WITH HIGHS EASILY TOPPING 100 DEGREES BY SATURDAY AND
POTENTIALLY EVEN REACHING OR TOPPING 105 DEGREES AS EARLY AS SUNDAY.
WIDESPREAD MODERATE HEATRISK IS EXPECTED OVER THE WEEKEND AS
AFTERNOON TEMPERATURES CLIMB TO ABOVE 100 DEGREES. THE HOTTEST
TEMPERATURES SHOULD FALL ON MONDAY AND/OR TUESDAY WITH THE LATEST
NBM INDICATING SOME WESTERN LOWER DESERTS REACHING 110 DEGREES TO
105-107 DEGREES IN THE PHOENIX AREA. THIS VERY WELL COULD RESULT IN
MAJOR HEATRISK ACROSS PORTIONS OF THE AREA FOR MONDAY AND TUESDAY,
SO EXTREME HEAT WATCHES/WARNINGS MAY EVENTUALLY BE NEEDED. SKIES ARE
LIKELY TO STAY FAIRLY CLEAR THROUGH AT LEAST MONDAY, BUT SOME HIGHER
CLOUDS MAY FINALLY MAKE THEIR WAY INTO THE REGION BY NEXT TUESDAY OR
WEDNESDAY DEPENDING ON WHAT HAPPENS WITH THE POTENTIAL CUT-OFF UPPER
LEVEL LOW. MODELS DO MOSTLY FAVOR THE RIDGE BREAKING DOWN DURING THE
LATTER HALF OF NEXT WEEK LIKELY LEADING TO A COOLING TREND. DESPITE
THIS, ABOVE NORMAL TEMPERATURES SHOULD PERSIST AS HIGHS LOOK TO STAY
CLOSE TO 100 DEGREES LATE NEXT WEEK.
AVIATION
UPDATED AT 0500Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR AVIATION WEATHER CONCERNS ARE EXPECTED DURING THE TAF
PERIOD. WINDS WILL FAVOR LIGHT AND DIURNAL TRENDS, WITH EXTENDED
PERIODS OF VRB TO CALM CONDITIONS OVERNIGHT. KPHX MAY EXPERIENCE
THE EVERY-SO-OFTEN OVERNIGHT SWITCH TO THE SW/W, BUT ANY SUCH
SHIFT SHOULD ONLY LAST A FEW HOURS AHEAD OF THE TYPICAL MORNING
E'RLY FLOW. OTHER THAN A FEW PASSING HIGH CLOUDS, SKIES WILL BE
MOSTLY CLEAR.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION WEATHER CONCERNS ARE EXPECTED DURING THE NEXT 24 HOURS
UNDER MOSTLY CLEAR SKIES. OUTSIDE OF PERIODS OF VRB TO CALM
CONDITIONS, WINDS WILL RANGE BETWEEN THE WSW AND NW AT KIPL, WHILE
KBLH SEES WINDOW OF N/NE FLOW DURING THE MID TO LATE MORNING AND
EARLY AFTERNOON HOURS.
FIRE WEATHER
A RAPID WARMING TREND OVER THE NEXT SEVERAL DAYS WILL PUSH READINGS
TO ABOVE NORMAL BY THURSDAY AND TO WELL ABOVE NORMAL STARTING THIS
WEEKEND. HUMIDITIES WILL ALSO QUICKLY LOWER WITH MINRHS DROPPING
TO AROUND 10% STARTING THURSDAY. HOWEVER, DESPITE THE DRIER AND
WARMER CONDITIONS, WINDS WILL BE FAIRLY LIGHT WITH ONLY PERIODIC
UPSLOPE GUSTS IN THE MID TEENS THROUGH THURSDAY. BREEZINESS SHOULD
PICK UP MORE FRIDAY INTO THE WEEKEND WITH GUSTS TO AROUND 20 MPH
EXPECTED. ALTHOUGH CONDITIONS FOR CRITICAL FIRE WEATHER WILL NOT
BE MET, SINGLE DIGIT MINRHS, WELL ABOVE NORMAL TEMPERATURES, AND
AFTERNOON UPSLOPE BREEZES MAY PRODUCE SOME AREAS OF ELEVATED FIRE
DANGER THIS WEEKEND INTO EARLY NEXT WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...WHITTOCK
LONG TERM...KUHLMAN
AVIATION...RW
FIRE WEATHER...WHITTOCK/KUHLMAN
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