505
FXUS65 KPSR 132339
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
439 PM MST TUE MAY 13 2025
UPDATE
UPDATED 00Z AVIATION DISCUSSION.
SYNOPSIS
A WEATHER DISTURBANCE PUSHING THROUGH THE REGION WILL RESULT IN
GUSTY WINDS SLOWLY WEAKENING AND TEMPERATURES FALLING INTO A BELOW
NORMAL RANGE THE NEXT COUPLE DAYS. HOWEVER, WEAK HIGH PRESSURE WILL
BUILD BACK INTO THE AREA ALLOWING TEMPERATURES TO MODERATE BACK TO
NEAR NORMAL LATER THIS WEEK. ANOTHER DRY WEATHER SYSTEM WILL SWEEP
INTO THE SOUTHWEST EARLY NEXT WEEK YIELDING ANOTHER ROUND OF GUSTY
WINDS AND COOLER THAN NORMAL TEMPERATURES.
DISCUSSION
EARLY AFTERNOON WV IMAGERY AND OBJECTIVE ANALYSIS DEPICTS NEGATIVE
HEIGHT ANOMALIES MIGRATING INTO THE GREAT BASIN WITH THE TROUGH BASE
AND ENHANCED JET CORE PROPAGATING THROUGH THE FORECAST AREA. WHILE
THE MOST ROBUST HEIGHT FALLS WILL REMAIN WELL NORTH OF THE CWA, DEEP
MIXING DEPTHS AND SUFFICIENT PRESSURE GRADIENT HAS RESULTED IN VERY
GUSTY WINDS IMPACTING MUCH OF THE REGION. NOT SURPRISINGLY, THE MOST
PRONOUNCED GUSTS HAVE BEEN MEASURED NEAR TERRAIN FEATURES, AND
VARIOUS HEADLINE PRODUCTS REMAIN IN EFFECT THROUGH THIS EVENING. AS
THE CIRCULATION CENTER EJECTS INTO THE CENTRAL/NORTHERN PLAINS
WEDNESDAY, GRADIENT WILL RELAX FORCING WINDS BACK INTO A MORE
TRADITIONAL LATE SPRING PATTERN. HOWEVER, H5 HEIGHTS WILL REMAIN
DEPRESSED IN A 570-574DM RANGE YIELDING HIGH TEMPERATURES SOME 4F-8F
BELOW THE DAILY NORMALS.
FOLLOWING THE PASSAGE OF THE AFOREMENTIONED TROUGH, BROAD
CYCLONIC/QUASI ZONAL FLOW WILL PREVAIL OVER THE SW CONUS THROUGH THE
REMAINDER OF THIS WEEK WITH H5 HEIGHTS ONLY GRADUALLY REBOUNDING
AROUND 576DM. AS THE LOWER/MIDDLE TROPOSPHERIC THERMAL PROFILES
MODERATE, MODEL GUIDANCE SPREAD REMAINS EXTREMELY NARROW
HIGHLIGHTING EXCELLENT FORECAST CONFIDENCE OF TEMPERATURES RETURNING
TO NEAR NORMAL LEVELS. FORECAST UNCERTAINTY INCREASES EARLY NEXT
WEEK AS OPERATIONAL AND ENSEMBLE GUIDANCE SHOW ANOTHER TROUGH WITH
DEEP NEGATIVE HEIGHT ANOMALIES PROPAGATING INTO THE GREAT BASIN.
ENSEMBLE MEMBERSHIP IS MOST DISPERSIVE WITH RESPECT TO THE DEPTH OF
THIS TROUGH AND EQUATORWARD EXTENT OF THE COLD CORE AND ASSOCIATED
VORTICITY CENTERS. OVERALL ENSEMBLE FORECAST TRENDS OF A DEEPER AND
SLOWER TROUGH EVOLUTION MATCHES A CONCEPTUAL PREFERRED FLOW PATTERN
UNDER THE CIRCUMSTANCES, AND WOULD STILL FAVOR THE SLOWER, DEEPER
MODEL FORECASTS. REGARDLESS, THERE IS SUFFICIENT MODEL AGREEMENT
SUGGESTING ANOTHER ROUND OF GUSTY WINDS AND COOLER TEMPERATURES
IMPACTING THE REGION DURING THE FIRST HALF OF NEXT WEEK.
AVIATION
UPDATED AT 2340Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:
GUSTY WSW WINDS WILL BE THE PRIMARY AVIATION CONCERN DURING THE
TAF PERIOD UNDER FEW HIGH CLOUDS. GUSTS TO AROUND 25 KTS WILL
PERSIST INTO EARLY THIS EVENING, EVENTUALLY SUBSIDING BY 03-04Z.
THOUGH W-SW WINDS ARE ANTICIPATED TO PREVAIL THROUGH THE OVERNIGHT
HOURS, DIRECTIONS MAY TRY TO SHIFT S-SE OR BECOME VRB FOR A PERIOD
EARLY WEDNESDAY MORNING. CONFIDENCE IS TOO LOW TO INCLUDE S-SE
WINDS EARLY WEDNESDAY MORNING AT ANY OF THE TERMINALS EXCEPT FOR
KIWA, SO HAVE OPTED FOR TEMPO VRB GROUPS AT THE OTHER SITES, WITH
SPEEDS AOB 6 KTS DURING THAT TIMEFRAME. WINDS WILL ONCE AGAIN
INCREASE LATE WEDNESDAY MORNING OUT OF THE WEST, BUT SPEEDS SHOULD
REMAIN MOSTLY AOB 11 KTS WITH OCCASIONAL AFTERNOON GUSTS INTO THE
UPPER TEENS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
GUSTY WINDS AND THE POTENTIAL FOR BRIEF VISIBILITY RESTRICTIONS
FROM BLOWING DUST WILL CONTINUE TO BE THE PRIMARY AVIATION
CONCERNS AT THE SOUTHEAST CALIFORNIA TERMINALS UNDER MOSTLY CLEAR
SKIES. WINDS WILL REMAIN WESTERLY AT KIPL AND SOUTHWESTERLY AT
KBLH THROUGH EARLY WEDNESDAY MORNING BEFORE SHIFTING NW AT BOTH
TERMINALS BETWEEN 10-15Z. AT KIPL, GUSTS OF 30-35 KT ARE EXPECTED
THROUGH MUCH OF THE EVENING AND WILL DECREASE AND EVENTUALLY
SUBSIDE DURING THE OVERNIGHT/EARLY MORNING HOURS. AT KBLH, GUSTS
TO AROUND 25 KTS WILL BE COMMON DURING THROUGH THE EARLY EVENING
AND SHOULD CEASE AROUND 04-05Z.
FIRE WEATHER
WEAKENING WIND SPEEDS AND COOLING TEMPERATURES WILL REDUCE THE FIRE
DANGER THE NEXT SEVERAL DAYS, HOWEVER ANOTHER INCOMING SYSTEM WILL
ALLOW WINDS TO STRENGTHEN AGAIN OVER THE WEEKEND. UNDER MORE TYPICAL
SPRINGTIME UPSLOPE GUSTINESS, MINIMUM HUMIDITY VALUES WILL FALL INTO
THE TEENS THE NEXT SEVERAL DAYS FOLLOWING POOR TO FAIR OVERNIGHT
RECOVERY OF 20-50%. GUSTY WINDS WILL MATERIALIZE AGAIN THIS WEEKEND
WITH THE NEXT WEATHER DISTURBANCE, HOWEVER COOLING TEMPERATURES AND
INCREASED HUMIDITY LEVELS MAY PRECLUDE WIDESPREAD CRITICAL
CONDITIONS. AT THIS TIME, SATURDAY AFTERNOON POSES THE GREATEST
THREAT OF AN ELEVATED FIRE DANGER.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...RED FLAG WARNING UNTIL 8 PM MST THIS EVENING FOR AZZ133.
CA...WIND ADVISORY UNTIL 5 AM PDT WEDNESDAY FOR CAZ562.
WIND ADVISORY UNTIL 2 AM PDT WEDNESDAY FOR CAZ563-566-567.
DISCUSSION...18/SMITH
AVIATION...WHITTOCK
FIRE WEATHER...18
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