079
FXUS65 KPSR 192346
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
446 PM MST TUE MAY 19 2026
UPDATE
UPDATED 00Z AVIATION DISCUSSION.
KEY MESSAGES
- A BROAD SCALE TROUGHING PATTERN WILL PERSIST OVER THE WESTERN
U.S. THROUGH THE END OF THE WORKWEEK KEEPING TEMPERATURES
OVERALL NEAR NORMAL.
- WEAK SHORTWAVE RIDGING WILL BUILD OVER THE DESERT SOUTHWEST
THIS WEEKEND,ALLOWING TEMPERATURES TO RISE A FEW DEGREES ABOVE
NORMAL, WITH LOWER DESERT HIGHS REACHING THE UPPER 90S TO AROUND
100 DEGREES.
- DRY CONDITIONS, WITH NO THREAT OF RAIN, AND SEASONAL AFTERNOON
BREEZES ARE EXPECTED THROUGH THE NEXT SEVERAL DAYS.
SHORT TERM /TODAY THROUGH THURSDAY/
LATEST GOES INFRARED WV IMAGERY AND 500 MB STREAMLINE ANALYSIS
REVEALS A BROAD TROUGH OF LOW PRESSURE EXTENDING FROM THE PACIFIC NW
INTO THE CENTRAL PLAINS. OUR FORECAST AREA STILL REMAINS AT THE BASE
OF THIS POSITIVELY TILTED TROUGH WITH A BROAD FETCH OF SOUTHWESTERLY
FLOW CURRENTLY IN PLACE OVER THE FORECAST AREA. A PLUME OF PACIFIC
MOISTURE IS CURRENTLY BEING PULLED NE INTO THE DESERT SOUTHWEST
THIS AFTERNOON WHICH IS RESULTING IN ABUNDANT HIGH CLOUD COVER.
DESPITE THE INCREASED CLOUDINESS, TEMPERATURES HAVE WARMED INTO
THE UPPER 80S TO LOWER 90S ACROSS THE LOWER DESERTS, SLIGHTLY
WARMER THAN YESTERDAY, BUT STILL AROUND 3 TO 5 DEGREES BELOW
NORMAL. VERY DRY AIR AT THE SFC (TD RANGING FROM THE SINGLE DIGITS
TO THE 20S) WILL AGAIN RESULT IN ANOTHER RELATIVELY COOL NIGHT
ACROSS THE REGION WITH LOWS RANGING FROM THE MID 50S TO UPPER 60S.
ON WEDNESDAY AND THURSDAY, THE TROUGHING PATTERN WILL REMAIN INTACT
OVER THE INTERMOUNTAIN WEST, WHICH WILL KEEP 500 MB HGHTS NEAR TO
SLIGHTLY BELOW SEASONAL LEVELS IN A 575-576 DAM RANGE. DESPITE THE
BELOW NORMAL 500 MB HGHT FIELD, THERE WILL BE A SLIGHT WARMING TREND
IN THE LOW-LEVEL THERMAL PROFILE WHICH WILL PROMOTE AT LEAST A
DEGREE OR TWO INCREASE IN TEMPERATURES MID-WEEK. THIS WILL RESULT IN
HIGHS REACHING BACK INTO THE MID TO UPPER 90S IN MOST LOWER DESERT
COMMUNITIES BOTH WEDNESDAY AND THURSDAY AFTERNOON. WINDS EACH DAY
WILL MOSTLY FOLLOW SEASONAL TRENDS; LIGHT WINDS DURING THE OVERNIGHT
AND MORNING HOURS AND MODEST UPSLOPE BREEZES IN THE AFTERNOONS WITH
GUSTS UP TO 15-25 MPH.
LONG TERM /FRIDAY THROUGH MONDAY/
THE SLOW WARMING TREND IS FORECAST TO CONTINUE THROUGH FRIDAY AND
THIS COMING WEEKEND. GLOBAL ENSEMBLE GUIDANCE SUPPORTS THE LARGE-
SCALE SYNOPTIC PATTERN ACROSS THE WEST FINALLY EVOLVING OUT OF
THE CURRENT STATE, WITH THE STRONG BLOCKING RIDGE NEAR B.C. CANADA
GIVING WAY/WEAKENING AS A STRONG LOW TRAVERSES ACROSS ALASKA.
THIS CHANGE WILL RESULT IN AT LEAST A TEMPORARY DE-AMPLIFICATION
OF THE PATTERN ACROSS THE WESTERN CONUS FOR THE WEEKEND AND A
TREND TOWARD POSITIVE 500MB HEIGHT ANOMALIES WITH BRIEF
ANTICYCLONIC FLOW DEVELOPING OVER THE DESERT SOUTHWEST. THIS
TREND WILL LEAD TO HIGH TEMPERATURES REACHING INTO THE UPPER 90S
BY FRIDAY AND PUSHING 100 DEGREES BY SUNDAY - MONDAY (30-60% ODDS
OF >=100).
THIS PATTERN SHIFT WILL ALSO ALLOW FOR SOME MOISTURE TO SEEP INTO
AZ, FROM THE SOUTHEAST AND WITH EVENING GULF SURGES, AS GLOBAL
GUIDANCE SHOWS A SLOW UPTREND IN PWATS FRIDAY THROUGH THE WEEKEND.
THIS MAY END UP LEADING TO SOME AZ HIGH TERRAIN AFTERNOON
CONVECTION, WHICH IS SUPPORTED BY SOME LOW-END NBM POPS THIS
WEEKEND (<25% OVER EASTERN AZ MOUNTAINS). THE ODDS ARE A LITTLE
HIGHER MONDAY WITH THE POTENTIAL FOR A WEAK PACIFIC LOW TO MOVE
INLAND FROM THE WEST, BUT THIS IS ABOUT ALL THAT CAN BE
ANTICIPATED THIS FAR OUT. THIS IS CLIMATOLOGICALLY THE DRIEST TIME
OF YEAR FOR THE AZ AND SOCAL LOWER DESERTS, SO IT IS HARD TO PUT
MUCH OPTIMISM INTO A LONG-RANGE PRECIP FORECAST FOR THE LOWER
DESERTS.
AVIATION
UPDATED AT 2345Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO AVIATION WEATHER CONCERNS ARE ANTICIPATED THROUGH THE FORECAST
PERIOD. W-SW WINDS WILL CONTINUE INTO THE OVERNIGHT HOURS, WITH
SPEEDS MAINLY AOB 10 KT. = THE DIURNAL EASTERLY SHIFT SHOULD OCCUR
LATE TONIGHT AT KIWA AND KPHX. A SLOW TRANSITION BACK TO W-SW IS
ANTICIPATED AGAIN TOMORROW WITH A FEW HOURS OF SOUTHERLY/VRB WINDS
EXPECTED PRIOR TO THE SHIFT. WINDS SHOULD GO W-SW BY 21Z. BKN HIGH
CIRRUS CLOUDS WILL CONTINUE THROUGH THE OVERNIGHT HOURS AND SLOWLY
CLEAR OUT TOMORROW AFTERNOON AND EVENING.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION WEATHER ISSUES WILL EXIST THROUGH THE FORECAST PERIOD
UNDER DECREASING HIGH CIRRUS DECKS. CURRENT NW WINDS WILL GO W
LATER TONIGHT AND CONTINUE THROUGH THE MORNING. WINDS WILL THEN GO
BACK NW AFTER SUNRISE TOMORROW. WIND GUSTS UP AROUND 20 KT WILL
CONTINUE AT KBLH FOR THE NEXT COUPLE OF HOURS. OTHERWISE WINDS, AT
BOTH TERMINALS, WILL BE AOB 10 KT.
FIRE WEATHER
THERE WILL BE A SLOW DAY-TO-DAY WARMING OF TEMPERATURES, BUT
OVERALL HIGH TEMPERATURES WILL REMAIN NEAR SEASONAL NORMALS
THROUGHOUT THE REST OF THIS WEEK. VERY DRY CONDITIONS WILL ALSO
PERSIST THROUGH THE END OF THE WEEK WITH RELATIVE HUMIDITY
BOTTOMING OUT AROUND 5-15% EACH DAY. THERE WILL BE A SLIGHT BUMP
UP IN MOISTURE LATE THIS WEEKEND/EARLY NEXT WEEK THAT MAY LEAD TO
ISOLATED DRY THUNDERSTORMS IN THE MOUNTAINS OF EASTERN AZ, BUT
MINIMUM RHS WILL STILL BE LOW AROUND 10-15%. OVERNIGHT RECOVERIES
WILL BE ALSO REMAIN POOR TO FAIR, MOSTLY AROUND 25-45%. SEASONAL
WIND PATTERNS ARE EXPECTED THROUGH THE REST OF THE WEEK, WITH
AFTERNOON UPSLOPE BREEZES UP TO 15-25 MPH. THERE WILL ALSO BE A
SLIGHT UPTICK IN SOUTHERLY UP-RIVER WINDS ALONG THE COLORADO
RIVER VALLEY FRIDAY THROUGH THIS WEEKEND, BUT AFTERNOON AND
EVENING GUSTS ARE CURRENTLY FORECAST TO TOP OUT IN THE 20-30 MPH
RANGE ALONG THE RIVER. THERE WILL ALSO LIKELY BE A RETURN OF
EVENING AND EARLY-OVERNIGHT GULF SURGE BOUNDARIES MOVING UP FROM
THE GULF OF CALIFORNIA THROUGH THE AZ DESERTS. THESE BOUNDARIES
WILL MOSTLY LEAD TO A BRIEF UPTICK IN WINDS AND SUDDEN
SOUTHWESTERLY WIND SHIFTS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...SALERNO
LONG TERM...BENEDICT
AVIATION...BERISLAVICH
FIRE WEATHER...BENEDICT/SALERNO
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