412
FXUS65 KPSR 311828
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1128 AM MST MON MAR 31 2025
UPDATE
UPDATED AVIATION DISCUSSION.
SYNOPSIS
SEASONABLY WARM TEMPERATURES AND AFTERNOON BREEZY CONDITIONS
CONTINUE TODAY. AN UNSETTLED WEATHER PATTERN TAKES HOLD TUESDAY,
WITH TEMPERATURES COOLING BELOW NORMAL THROUGH THE REMAINDER OF THE
WORKWEEK. TUESDAY IS ALSO EXPECTED TO BE THE WINDIEST DAY, WITH THE
STRONGEST WINDS EXPECTED OVER SOUTHEAST CALIFORNIA AND THE HIGH
TERRAIN EAST OF PHOENIX. SLIGHT CHANCES FOR LIGHT SHOWERS EXIST ON
WEDNESDAY AND FRIDAY, BUT THESE CHANCES ARE CONFINED TO THE HIGHER
TERRAIN TO THE NORTH AND EAST OF PHOENIX.
DISCUSSION
THE UPPER LEVEL PATTERN EARLY THIS MORNING IS CHARACTERIZED BY
STRONG ZONAL FLOW ALOFT ASSOCIATED WITH AN EAST PACIFIC JET STREAK
THAT STRETCHES INTO THE GREAT BASIN, WITH BROAD CYCLONIC CIRCULATION
TO ITS NORTH JUST OFF THE PACIFIC NORTHWEST COAST. OUR REGION IS
SOUTH OF THE AFOREMENTIONED JET, BENEFITING FROM SLIGHTLY ABOVE
AVERAGE MID-LEVEL HEIGHTS, AND SO WE CAN EXPECT ONE MORE DAY OF
SEASONABLY WARM TEMPERATURES ACROSS OUR LOWER DESERTS. AFTERNOON
HIGHS SHOULD RANGE MOSTLY IN THE LOWER TO MIDDLE 80S TODAY.
ENSEMBLES SHOW THE JET ACQUIRING CYCLONIC CURVATURE AND SHIFTING
SOUTHWARD OVER THE NEXT 36-48 HOURS AS LONGWAVE TROUGHING MOVES
ONSHORE AND SETTLES OVER THE WESTERN CONUS. AS A RESULT, WINDS ALOFT
WILL INCREASE THROUGH TUESDAY, AND DAYTIME MIXING WILL BE CAPABLE OF
BRINGING THIS HIGHER MOMENTUM AIR DOWN TO THE SURFACE ACROSS MUCH OF
THE FORECAST AREA. TODAY, THE STRONGEST WINDS WILL BE FOCUSED OVER
THE WESTERN DESERTS DURING THE AFTERNOON AND EVENING, WITH
WIDESPREAD GUSTS TO 25-35 MPH AND LOCALLY HIGHER. WITH HIGH HREF
PROBABILITIES (60-100%) OF 40+ MPH GUSTS OVER PORTIONS OF WESTERN
IMPERIAL COUNTY AND JTNP, INCLUDING THE IMPERIAL VALLEY, WIND
ADVISORIES HAVE BEEN ISSUED FOR THOSE AREAS VALID 3 PM - 11 PM PDT
TODAY. EXPECT STRONGER WINDS AREAWIDE TUESDAY, WITH THE HIGHEST GUST
SPEEDS STILL FOCUSED OVER SE CA AND HIGH TERRAIN EAST OF PHOENIX.
WESTERN IMPERIAL COUNTY WILL SEE SLIGHTLY STRONGER GUSTS TUESDAY
AFTERNOON/EVENING THAN TODAY, AND SO A WIND ADVISORY HAS ALSO BEEN
ISSUED FOR THAT TIME. AS WESTERLY WINDS PEAK TUESDAY AFTERNOON INTO
THE EVENING, THIS WILL ALSO BE THE MOST LIKELY TIMING FOR BLOWING
DUST TO CAUSE TRAVEL CONCERNS IF ANY DENSER CHANNELS DEVELOP.
OTHER THAN WIND-RELATED IMPACTS, THE LONGWAVE TROUGHING PATTERN
MOVING INTO THE WESTERN CONUS WILL BRING COOLER TEMPERATURES TUESDAY
THROUGH THE END OF THE WORKWEEK AND SHOULD SEND SEVERAL SHORTWAVES
OVER THE AREA. ONE SUCH SHORTWAVE IS LIKELY TO MOVE OVERHEAD
WEDNESDAY. THIS SHORTWAVE WILL BE CAPABLE OF PRODUCING SOME LIGHT
SHOWERS FOCUSED MOSTLY OVER HIGH TERRAIN NORTH AND EAST OF PHOENIX,
DESPITE A NOT-SO-FAVORABLE MOISTURE PROFILE (MOST MOISTURE FOCUSED
BETWEEN 650-750 MB). AS THIS SHORTWAVE MOVES OVERHEAD, ENSEMBLES
ALSO ADVERTISE SOME OF THE COOLEST 850 MB TEMPERATURES SETTLING
INTO THE REGION, WITH NAEFS MEAN VALUES AROUND 3 DEG C (BELOW THE
10TH PERCENTILE OF CLIMATOLOGY.) AS SUCH, LATEST NBM FORECAST
HIGHS DEPICT THE LOWER DESERTS OF SOUTH-CENTRAL AZ STRUGGLING TO
GET OUT OF THE 60S ON WEDNESDAY. ANOTHER SHORTWAVE LOOKS TO MOVE
ACROSS THE REGION LATE WEEK, BRINGING SLIGHT CHANCES FOR SHOWERS
(15-25%) TO THE HIGH TERRAIN EAST OF PHOENIX FRIDAY.
BY NEXT WEEKEND, MOST GUIDANCE INDICATES THE LONGWAVE TROUGH HAVING
EVOLVED INTO A CLOSED UPPER LEVEL LOW, WHICH WILL REMAIN IN PLACE
SOMEWHERE OVER THE SOUTHWEST US. THE RESULTANT NEW PATTERN RESEMBLES
A REX BLOCK, AS STRONG POSITIVE HEIGHT ANOMALIES BUILD OVER THE
NORTHWEST US AND WESTERN CANADA. REGARDLESS, POPS REMAIN VERY LOW
AND CONFINED TO THE AZ HIGH TERRAIN AT THIS TIME FOR NEXT WEEKEND,
AND AS THE CUTOFF LOW GRADUALLY WEAKENS AND MEANDERS EASTWARD,
TEMPERATURES SHOULD WARM BACK INTO THE 80S.
AVIATION
UPDATED AT 1827Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
SOUTH TO SOUTHEAST WINDS WILL CONTINUE TO VEER TOWARD A
WEST/SOUTHWEST COMPONENT HEADING INTO THIS AFTERNOON. SPEEDS WILL
INCREASE THIS AFTERNOON WITH GUSTS CLIMBING TO AROUND 20-25 KTS
AND BRIEFLY HIGHER AT TIMES BEFORE SUBSIDING THIS EVENING. CAN'T
RULE OUT SOME DUST GETTING LOFTED TO CREATE SOME SLANTWISE
VISIBILITY CONCERNS THROUGH AROUND SUNSET. WIND DIRECTIONS ARE
FORECAST TO REMAIN OUT OF THE WEST/SOUTHWEST THROUGH THE PERIOD
WITH NO OVERNIGHT EASTERLY SHIFT ANTICIPATED. SCT, TO AT TIMES
BKN, HIGH CIRRUS CLOUDS WILL BE COMMON THROUGHOUT THE PERIOD WITH
PERHAPS A FEW LOW CUMULUS AT AROUND 6 KFT POSSIBLE DURING THE
AFTERNOON HOURS.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
STRONG WINDS WILL BE THE MAIN AVIATION WEATHER ISSUE THROUGHOUT
THE TAF PERIOD. KIPL WILL SEE STRONG WESTERLY GUSTS UPWARDS OF
25-30 KTS CONTINUE THROUGHOUT THE EVENING WITH SOME STRONGER GUSTS
TO AROUND 35 KTS POSSIBLE AT TIMES THIS AFTERNOON INTO THE
EVENING. AS A RESULT, BLOWING DUST WILL BE A CONCERN THAT COULD
RESULT IN LOWERED SURFACE AND/OR SLANTWISE VISIBILITIES. EXPECT
THESE STRONGER GUSTS TO SUBSIDE DURING THE OVERNIGHT HOURS WHILE
SUSTAINED WINDS REMAIN ELEVATED. AT KBLH, WINDS WILL FAVOR A
SOUTHWESTERLY COMPONENT WITH AFTERNOON AND EARLY EVENING GUSTS
INCREASING INTO THE 20-25 KT RANGE BEFORE GRADUALLY SUBSIDING
DURING THE LATE EVENING HOURS. SCT, TO AT TIMES BKN, HIGH-CIRRUS
CLOUDS WILL COMMON THROUGHOUT THE PERIOD WITH PERHAPS A FEW LOW
CUMULUS AT AROUND 5 KFT, MAINLY NEAR KIPL, POSSIBLE THROUGH THE
AFTERNOON HOURS.
FIRE WEATHER
SEASONAL TEMPERATURES ARE EXPECTED TODAY WITH TEMPERATURES
COOLING BELOW NORMAL BY TUESDAY AND REMAINING BELOW NORMAL THROUGH
THE REMAINDER OF THE WORKWEEK. MOSTLY DRY CONDITIONS ARE EXPECTED
THROUGHOUT THE WEEK AS WELL, WITH THE EXCEPTION OF SLIGHT CHANCES
FOR RAIN ON WEDNESDAY AFTERNOON AND AGAIN FRIDAY, BUT THESE
CHANCES WILL BE CONFINED TO THE HIGHER TERRAIN TO THE NORTH AND
EAST OF PHOENIX. TODAY WILL BE BREEZY, PARTICULARLY ACROSS THE
WESTERN DESERTS, HOWEVER, THE STRONGEST WINDS ARE EXPECTED ON
TUESDAY. EXPECT THE HIGHEST WIND SPEEDS ACROSS SE CA, MAINLY
IMPERIAL COUNTY, AND ACROSS THE HIGHER TERRAIN OF MARICOPA AND
GILA COUNTIES, WHERE ELEVATED FIRE WEATHER CONCERNS WILL EXIST.
MINIMUM RELATIVE HUMIDITY IS EXPECTED TO RANGE FROM 15-25% MOST
AFTERNOONS THROUGH THE WORKWEEK, AND OVERNIGHT RECOVERIES WILL BE
FAIR AND GENERALLY AROUND 40-60%.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING
FOR CAZ560-566-567.
WIND ADVISORY UNTIL 2 AM PDT WEDNESDAY FOR CAZ562.
WIND ADVISORY FROM 3 PM TO 11 PM PDT TUESDAY FOR CAZ566-567.
DISCUSSION...WHITTOCK
AVIATION...SMITH
FIRE WEATHER...WHITTOCK/BERISLAVICH
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