031
FXUS65 KPSR 230440
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
940 PM MST FRI MAY 22 2026
UPDATE...UPDATED 06Z AVIATION DISCUSSION
KEY MESSAGES
- TEMPERATURES WILL HOVER NEAR TO SLIGHTLY ABOVE NORMAL THROUGH
EARLY NEXT BEFORE MODEST COOLING ARRIVES.
- DRY CONDITIONS WILL PREVAIL THROUGH EARLY NEXT WEEK WITH
TYPICAL AFTERNOON BREEZINESS.
- A SLIGHT CHANCE OF THUNDERSTORMS WILL EXIST OVER THE EASTERN
ARIZONA HIGH TERRAIN EARLY NEXT WEEK, ALBEIT WITH LIMITED
RAINFALL POTENTIAL.
SHORT TERM /TODAY THROUGH SUNDAY/
A SPLIT JET REGIME CONTINUES TO EVOLVE OVER THE EASTERN PACIFIC
AND ONSHORE ALONG THE WEST COAST OF NORTH AMERICA. A BROAD AREA OF
MIDLEVEL ANTICYCLONIC FLOW OFFSHORE AND CYCLONIC CURVATURE OVER
WEST-CENTRAL CONUS IS EVIDENT IN WATER VAPOR IMAGERY AND 500 MB
RAP ANALYSIS EARLY THIS AFTERNOON. WITHIN THE BROADER FLOW, A FEW
SHORTWAVES ARE PRESENT, ONE EMBEDDED IN THE NORTHERN STREAM
CURRENTLY CENTERED OVER SOUTH DAKOTA, AND ANOTHER, WEAKER
DISTURBANCE ASSOCIATED WITH THE SUBTROPICAL JET SLIDING EASTWARD
OVER BAJA CALIFORNIA. AS A RESULT OF THIS SETUP, PRIMARILY THE
WEAKER SOUTHERN SYSTEM NEAR THE DESERT SOUTHWEST, THE FORECAST
AREA REMAINS UNDER NEGATIVE HEIGHT ANOMALIES. HOWEVER, CLEAR SKIES
AND INTENSE DAYTIME INSOLATION TYPICAL OF LATE MAY ARE LIKELY TO
RESULT IN NEAR NORMAL LOWER DESERT HIGHS IN THE MIDDLE TO UPPER
90S TODAY, DESPITE THE NEGATIVE HEIGHT ANOMALIES ALOFT.
OVER THE NEXT 36-48 HOURS, NEGATIVE HEIGHT ANOMALIES WILL
SHIFT INTO THE SOUTHERN PLAINS, WITH A TRANSIENT SHORTWAVE RIDGE
BUILDING OVER THE SOUTHWEST US OVER THE WEEKEND. ENSEMBLE MEAN H5
HEIGHTS ARE FORECAST TO PEAK BETWEEN 581-583 DAM ON SUNDAY,
SUPPORTING WARMING TEMPERATURES OVER THE WEEKEND, WITH HIGHS NEAR
100F FOR SOME OF THE WARMEST SPOTS ACROSS THE LOWER DESERTS ON
SUNDAY. OTHERWISE, ANTICIPATE DRY AND TRANQUIL CONDITIONS WITH ONLY
MODEST AFTERNOON BREEZINESS THROUGH THE WEEKEND.
LONG TERM /MONDAY THROUGH THURSDAY/
THE FIRST HALF OF NEXT WEEK WILL BE CHARACTERIZED BY HEIGHT FALLS
OVER THE SW CONUS AS STRONG TROUGHING ENTERING THE PACIFIC NW AND
GREAT BASIN COMBINES WITH A WEAK SHORTWAVE AND ENHANCED
SUBTROPICAL JET PROPAGATING ACROSS SOUTHERN CALIFORNIA/NORTHWEST
MEXICO. A BRIEF PERIOD OF DEEPLY MERIDIONAL FLOW SHOULD IMPORT
MARGINALLY BETTER MOISTURE PROFILES INTO THE EASTERN PARTS OF THE
FORECAST AREA, HOWEVER MODELS CONTINUE TO INDICATE NO MORE THAN 5
G/KG WITHIN THE BOUNDARY LAYER. THE INTENSITY OF THIS SHORTWAVE
AND ASSOCIATED SUBTROPICAL JET ARE UNUSUALLY STRONG FOR THIS TIME
OF YEAR, AND PATTERN RECOGNITION SUGGESTS ROBUST JET FORCED ASCENT
AND INCREASED MOISTURE INTERACTING WITH THE COOLING ALOFT AND
STEEPENING LAPSE RATES OVER THE HIGHER TERRAIN OF EASTERN ARIZONA
MONDAY AFTERNOON. WHILE INSTABILITY WILL LIKELY BE LIMITED, DEEP
MOUNTAIN CONVECTION SHOULD DEVELOP OVER PARTS OF SOUTHERN GILA
COUNTY, THOUGH THERMODYNAMIC PROFILES INDICATE A SUBSTANTIAL
AMOUNT OF EVAPORATION WHICH WOULD FAVOR DRY LIGHTNING STRIKES AND
GUSTY OUTFLOW WINDS VERSUS ACCUMULATING RAINFALL. ASSUMING THIS
EVOLUTION COME TO FRUITION, THE GREATEST CONCERN WOULD BE WILDFIRE
STARTS IN REMOTE HIGH TERRAIN AREAS.
FORECAST CONFIDENCE DETERIORATES TOWARDS THE MIDDLE OF NEXT WEEK IN
RESPONSE TO A DEVELOPING BLOCKING PATTERN OVER THE WESTERN
HEMISPHERE. RECENT GFS AND ECMWF OPERATIONAL ITERATIONS HAVE SIDED
MORE TOWARDS THE MAJORITY OF CMC ENSEMBLE MEMBERS DEPICTING A SLOW
MOVING, CLOSED CIRCULATION HOVERING OVER THE GREAT BASIN UNTIL THE
END OF THE WEEK. HOWEVER, GEFS MEMBERS ARE SURPRISINGLY FAR MORE
DISPERSIVE THAN THEIR CMC COUNTERPARTS WITH MANY MEMBERS SHOWING A
FAR LESS INTENSE AND LESS CUTOFF NEGATIVE HEIGHT ANOMALY. GIVEN THE
PREFERENCE TOWARDS A BLOCKING PATTERN, WOULD FAVOR THE SLOWER, MORE
CLOSED CIRCULATION OUTCOME IN THIS FORECAST WHICH WOULD BE MORE APT
TO YIELD AREAS OF STRONGER WINDS, ALBEIT WITH MORE IMPACTFUL SPEEDS
RELEGATED TO NORTHERN ARIZONA. THAT SAID, IT WOULD NOT BE UNEXPECTED
TO SEE FUTURE AUTOMATED NBM/WPC MANDATED FORECASTS ADVERTISE
STRONGER WIND GUSTS IN THE WED-THURS TIME FRAME ONCE THESE ENSEMBLE
BLENDS CONVERGE ON A SIMILAR PATTERN.
AVIATION
UPDATED AT 0435Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO AVIATION WEATHER CONCERNS UNDER MOSTLY CLEAR SKIES CAN BE
EXPECTED THROUGHOUT THE TAF PERIOD. THE OVERALL WIND PATTERN WILL
FOLLOW THE TYPICAL DIURNAL TENDENCIES WITH SPEEDS GENERALLY AOB 10
KTS, WITH SOME OCCASIONAL AFTERNOON/EARLY EVENING GUSTINESS IN
THE MID TO UPPER TEENS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION CONCERNS UNDER CLEAR SKIES CAN BE EXPECTED THROUGHOUT
THE TAF PERIOD. AT KIPL, WINDS WILL GENERALLY BE OUT OF THE
SOUTHEAST WHILE AT KBLH, WINDS WILL GENERALLY BE OUT OF THE SOUTH.
OVERALL WIND SPEEDS WILL RANGE BETWEEN 5-13 KTS, WITH SOME
ELEVATED GUSTS SATURDAY AFTERNOON, ESPECIALLY AT KBLH.
FIRE WEATHER
TEMPERATURES WILL REMAIN IN A SLIGHTLY ABOVE NORMAL CATEGORY THROUGH
EARLY NEXT WEEK BEFORE SLIGHT COOLING DURING THE MIDDLE OF THE WEEK.
MINIMUM AFTERNOON HUMIDITY LEVELS WILL FALL INTO A 10-20% RANGE WITH
POOR TO FAIR OVERNIGHT RECOVERY OF 20-40% IMPROVING SOMEWHAT NEXT
WEEK. A MARGINAL INCREASE IN MOISTURE EARLY NEXT WEEK MAY LEAD TO A
SLIGHT CHANCE FOR AFTERNOON/EVENING STORMS AND LIGHTNING STRIKES
OVER HIGH TERRAIN OF EASTERN DISTRICTS. THIS WOULD MOST LIKELY OCCUR
MONDAY, AND WITH LITTLE TO NO ACCUMULATING RAINFALL, THE THREAT FOR
NEW WILDFIRE STARTS DUE TO LIGHTNING STRIKES WILL BE HEIGHTENED. THE
TYPICAL AFTERNOON SPRING UPSLOPE GUSTINESS OF 15-25 MPH WILL BE
COMMON THROUGH THE PERIOD WITH THE MOST PRONOUNCED GUSTS OVER
EASTERN DISTRICT HIGH TERRAIN AND THROUGH THE LOWER COLORADO RIVER
VALLEY DURING THE MIDDLE OF NEXT WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...WHITTOCK/18
LONG TERM...18
AVIATION...LOJERO
FIRE WEATHER...18
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