070
FXUS65 KPSR 301755
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1055 AM MST SUN MAR 30 2025
UPDATE
UPDATED 18Z AVIATION DISCUSSION.
SYNOPSIS
SEASONABLY WARM TEMPERATURES WILL PREVAIL THROUGH MONDAY, WITH HIGHS
REACHING THE LOWER TO MIDDLE EIGHTIES ACROSS THE LOWER DESERTS. A
PATTERN CHANGE WILL OCCUR DURING THE MIDDLE OF THE UPCOMING WORKWEEK
AS A LOW PRESSURE SYSTEM ENTERS THE DESERT SOUTHWEST. BREEZY
CONDITIONS WILL BE COMMON EACH AFTERNOON THROUGH THE MIDDLE OF THE
WEEK, PARTICULARLY FOR PORTIONS OF SOUTHEAST CALIFORNIA AND THE
ARIZONA HIGH TERRAIN, BUT THE STRONGEST WINDS AREAWIDE ARE EXPECTED
ON TUESDAY. BELOW NORMAL TEMPERATURES WILL PREVAIL STARTING TUESDAY
AND THROUGH THE REMAINDER OF THE WORKWEEK.
DISCUSSION
CURRENT MID-LEVEL WV IMAGERY DEPICTS THE REGION UNDER FAIRLY STRONG
ZONAL FLOW ALOFT, WITH A WEAK SHORTWAVE ENTERING THE SOUTHWEST US
AND BRINGING SCATTERED CIRRUS DECKS OVERHEAD EARLY THIS MORNING.
THIS SHORTWAVE WILL IMPACT SENSIBLE WEATHER VERY LITTLE OTHER THAN
MAINTAINING SIMILARLY BREEZY CONDITIONS TO THAT OF THE LAST SEVERAL
DAYS AND NEAR NORMAL TEMPERATURES ACROSS THE FORECAST AREA TODAY. AS
SUCH, FORECAST HIGHS FOR THE LOWER DESERTS ARE IN THE LOWER TO
MIDDLE 80S. THE UPPER LEVEL FLOW WILL SUBTLY CHANGE MONDAY, AS THE
WEAK SHORTWAVE WILL HAVE PASSED WELL TO THE EAST, AND ENSEMBLES SHOW
H5 HEIGHTS TEMPORARILY INCREASING TO AROUND 578 DM. THIS SHOULD
RESULT IN A SLIGHT WARMING OF AFTERNOON HIGHS BY A FEW DEGREES.
A PATTERN SHIFT IS THEN EXPECTED AS WE HEAD INTO THE MIDDLE OF THE
UPCOMING WORKWEEK, AS A BROAD AREA OF STRONGLY NEGATIVE H5 HEIGHT
ANOMALIES ENTERS THE WESTERN CONUS. ENSEMBLES SHOW THIS LONGWAVE
TROUGHING FEATURE INCREASING IN AMPLITUDE AS IT MOVES OVER THE
WESTERN CONUS, BRINGING EVEN STRONGER ZONAL FLOW ALOFT AS IT DIGS
SOUTHWARD INTO THE DESERT SOUTHWEST. STRONG PRESSURE PACKING AND
700MB WINDS UP TO 40-50 KTS TUESDAY, AS THE LONGWAVE TROUGH DROPS
DOWN INTO THE AREA, WILL LEAD TO WIDESPREAD BREEZY TO WINDY
CONDITIONS. LATEST NBM GUIDANCE CONTINUES TO ADVERTISE WIDESPREAD
SURFACE WIND GUSTS TO BETWEEN 25-40 MPH AND LOCALLY HIGHER. WITH
HIGH CONFIDENCE IN CONTINUED STRONG, GUSTY WINDS FOR THE SW CORNER
OF IMPERIAL COUNTY, THE WIND ADVISORY THERE HAS BEEN EXTENDED
THROUGH TUESDAY NIGHT. ADDITIONAL WIND HEADLINES MAY NEED TO BE
CONSIDERED ON TUESDAY FOR MUCH OF WESTERN IMPERIAL COUNTY AND THE
SOUTH-CENTRAL AZ HIGH TERRAIN (EAST OF PHOENIX.)
IN ADDITION TO THE WINDY CONDITIONS TUESDAY, THIS PATTERN CHANGE
WILL RESULT IN COOLER TEMPERATURES THROUGH THE REMAINDER OF THE
UPCOMING WORKWEEK. TEMPERATURES WILL DROP TO AROUND 5-10 DEGREES
BELOW NORMAL FOR THE TIME OF YEAR STARTING TUESDAY, MEANING LOWER
DESERT HIGHS IN THE LOWER TO MIDDLE 70S. UNFORTUNATELY, THE
PROSPECT FOR RAIN IS NOT GREAT WITH THIS LONGWAVE TROUGHING
PATTERN. AT LEAST NOT FOR THE LOWER DESERTS, DUE LARGELY TO THE
MORE CONTINENTAL TRACK OF THE TROUGH AND SEASONAL TO SUB-SEASONAL
MOISTURE LEVELS. LATEST NBM POPS HAVE DROPPED SIGNIFICANTLY DURING
THE SECOND HALF OF NEXT WEEK. POPS NOW MAX OUT AROUND 10-15% IN
THE LOWER DESERTS OF SOUTH-CENTRAL AZ ON FRIDAY, WITH SLIGHTLY
HIGHER POPS IN THE HIGHER TERRAIN.
BY NEXT WEEKEND, MOST ENSEMBLE GUIDANCE INDICATES THE LONGWAVE
TROUGH EVOLVING INTO A CUTOFF LOW, WHICH WILL REMAIN IN PLACE
SOMEWHERE OVER THE SOUTHWEST US. THE RESULTANT NEW PATTERN RESEMBLES
A REX BLOCK, AS GUIDANCE SHOWS STRONG POSITIVE HEIGHT ANOMALIES
BUILDING OVER THE NORTHWEST US AND WESTERN CANADA. REGARDLESS, POPS
REMAIN LOW AT THIS TIME FOR NEXT WEEKEND, AND AS THE CUTOFF LOW
GRADUALLY WEAKENS AND MEANDERS, TEMPERATURES SHOULD WARM BACK INTO
THE 80S BY NEXT SUNDAY.
AVIATION
UPDATED AT 1754Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
A PERSISTENCE OF CONDITIONS SIMILAR TO THE PREVIOUS 24-48 HRS WILL
CONTINUE THROUGH THE NEXT 24 HRS, WITH VFR CONDITIONS AND SOME
AFTERNOON BREEZINESS. WESTERLY WIND GUSTS TO AROUND 20 KTS ARE
EXPECTED THIS AFTERNOON. DIRECTIONS WILL SHIFT BACK EAST TONIGHT
BY AROUND MIDNIGHT AND BACK WESTERLY AGAIN BY 19-20Z TOMORROW. FEW
TO SCT CIRRUS WILL CONTINUE PASSING OVERHEAD WITH FEW CLOUDS DOWN
TO 12K FT AGL TODAY AND POTENTIALLY FEW CUMULUS AROUND 5-6K FT AGL
TOMORROW AFTERNOON.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
BREEZY AFTERNOON AND EVENING CONDITIONS WILL BE THE PRIMARY
AVIATION IMPACT. AT KIPL, WESTERLY WINDS WILL PERSIST THROUGHOUT
THE ENTIRE PERIOD WITH ANOTHER ROUND OF ENHANCED AFTERNOON/EARLY
EVENING GUSTS TO AROUND 25 KTS. AT KBLH, SOUTHWESTERLY WINDS TAKE
HOLD BY THIS AFTERNOON WITH SPEEDS RANGING BETWEEN 10-15 KTS, WITH
SOME GUSTS TO AROUND 20 KTS LATE THIS AFTERNOON. FEW-SCT HIGH
CLOUDS WILL BE COMMON THROUGHOUT THE PERIOD.
FIRE WEATHER
SEASONAL TEMPERATURES, DRY CONDITIONS, AND AFTERNOON BREEZINESS ARE
EXPECTED THROUGH MONDAY. EACH DAY DOES LOOK TO BE PROGRESSIVELY
WINDIER FROM TODAY THROUGH TUESDAY. THE STRONGEST WINDS WILL
RESIDE ACROSS THE WESTERN DISTRICTS AND HIGHER TERRAIN OF MARICOPA
AND GILA COUNTIES, WHERE ELEVATED FIRE WEATHER CONCERNS WILL
EXIST. THE STRONGEST WINDS, AND SUBSEQUENTLY THE HIGHEST FIRE
WEATHER CONCERNS FOR THE FORECAST AREA, ARE EXPECTED ON TUESDAY.
MINIMUM RELATIVE HUMIDITY IS EXPECTED TO RANGE FROM 15-20% MOST
AFTERNOONS, INCLUDING TUESDAY, AND OVERNIGHT RECOVERIES WILL BE
FAIR AROUND 40-60%. BELOW NORMAL TEMPERATURES WILL PREVAIL
STARTING TUESDAY AND THROUGH THE REMAINDER OF THE WORKWEEK, AND
THERE IS A LOW CHANCE (10-20%) FOR SOME LIGHT SHOWERS LATE WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...WIND ADVISORY UNTIL 2 AM PDT WEDNESDAY FOR CAZ562.
DISCUSSION...WHITTOCK
AVIATION...BENEDICT
FIRE WEATHER...WHITTOCK/BENEDICT
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