489
FXUS65 KPSR 290517
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1017 PM MST FRI MAR 28 2025
UPDATE
UPDATED 06Z AVIATION DISCUSSION.
SYNOPSIS
SEASONAL TEMPERATURES, DRY CONDITIONS, AND DAILY BREEZINESS ARE
EXPECTED THROUGH AT LEAST EARLY NEXT WEEK. LOWER DESERT HIGH
TEMPERATURES WILL HOVER IN THE LOW TO MID EIGHTIES. A PATTERN SHIFT
TOWARD THE MIDDLE AND SECOND HALF OF NEXT WEEK WILL HAVE THE
POTENTIAL TO BRING BELOW NORMAL TEMPERATURES, A SHOT AT SOME RAIN,
AND MORE BREEZY TO WINDY CONDITIONS.
DISCUSSION
A SHORTWAVE TROUGH IS SEEN VERY CLEARLY ON MIDLEVEL WV SATELLITE
THIS AFTERNOON, MOVING THROUGH THE REGION. THIS SHORTWAVE HAS HELPED
COOL TEMPERATURES BACK DOWN A LITTLE CLOSER TO NORMAL AND BROUGHT
SOME THICKER HIGH CLOUDS AND SOME HIGH LEVEL VIRGA THAT HAS BEEN
VISIBLE AS WEAK ECHOES ON RADAR. THIS SHORTWAVE HAS ALSO LED TO A
TIGHTENING OF THE PRESSURE GRADIENT AND BREEZY TO LOCALLY WINDY
CONDITIONS. THE STRONGEST WINDS HAVE BEEN ACROSS IMPERIAL COUNTY CA
OVER THE PAST 12 HOURS, WITH THE INFLUENCES OF DOWNSLOPING AND
POSSIBLE MOUNTAIN ROTORS. WIND GUSTS IN THE IMPERIAL VALLEY HAVE
REACHED UP TO 30-40 MPH AND THE SOUTHWEST CORNER OF THE COUNTY HAS
REACHED 50-55 MPH, WHERE A WIND ADVISORY REMAINS IN EFFECT. IMPERIAL
COUNTY WILL REMAIN THE BREEZIEST SPOT. LIGHTER BREEZINESS IS
EXPECTED ELSEWHERE, WITH THE LOWER DESERTS MOSTLY AROUND 20-25 MPH
GUSTS TO 25-35 MPH IN THE HIGHER TERRAIN NORTH AND EAST OF PHOENIX.
THIS DOES LOOK LIKE IT WILL BE A DAILY OCCURRENCE THROUGH THIS
WEEKEND, AND POSSIBLY THROUGH ALL OF NEXT WEEK, AS THE SOUTHWEST
WILL BE UNDER A QUASI-ZONAL FLOW REGIME WITH A COUPLE MORE SHORTWAVE
TROUGHS PASSING QUICKLY BY THROUGH THIS WEEKEND. THIS REGIME WILL
ALSO KEEP TEMPERATURES CLOSE TO SEASONAL LEVELS, THROUGH AT LEAST
EARLY NEXT WEEK, WITH AFTERNOON HIGHS IN THE LOW TO MID 80S FOR THE
LOWER DESERTS.
THERE STILL REMAINS A HIGH DEGREE OF UNCERTAINTY IN THE WEATHER
FORECAST FROM WEDNESDAY THROUGH THE END OF NEXT WEEK, AT LEAST AS
FAR AS THE SPECIFIC SENSIBLE WEATHER IMPACTS (I.E. TEMPERATURES,
WIND MAGNITUDES, AND RAIN CHANCES). THERE IS GOOD CONFIDENCE IN A
WEATHER PATTERN SHIFT GOING INTO NEXT WEEK, FAVORING A MORE
AMPLIFIED PATTERN ACROSS THE WESTERN CONUS AS A RESULT OF AN
UPSTREAM BLOCKING PATTERN DEVELOPING IN THE CENTRAL PACIFIC. GLOBAL
ENSEMBLES SUPPORT INCREASED NEGATIVE HEIGHT ANOMALIES ACROSS THE
WESTERN CONUS BEGINNING AROUND WEDNESDAY, WITH AROUND 50% OF MEMBERS
MAINTAINING NEGATIVE HEIGHT ANOMALIES THROUGH NEXT WEEKEND. THE MAIN
UNCERTAINTY WILL BE THE DEPTH OF LONGER WAVE TROUGHS ACROSS THE
WEST, TIMING OF TROUGHS, AND HOW PROGRESSIVE OR SLOW-MOVING THEY MAY
BE. A LOT OF THE VARIANCE IN THE GRAND ENSEMBLE IS STILL BEING
DRIVEN BY A SPLIT IN SOLUTIONS BETWEEN THE LESS AMPLIFIED GEFS
MEMBERSHIP AND HIGHER AMPLIFIED/DEEPER TROUGH ENS & GEPS
MEMBERSHIPS. WITH THE LATEST 12Z ENSEMBLES, THE GEFS MEAN 500MB
HEIGHTS OVER AZ HAS MADE A SLIGHT SHIFT TOWARD THE LOWER
HEIGHTS/DEEPER SOLUTIONS. DEEPER SOLUTIONS WILL OFFER BETTER RAIN
CHANCES, COOLER TEMPERATURES, AND BREEZIER WINDS. IT IS STILL A TOO
EARLY TO TALK SPECIFICS ON RAIN POTENTIAL, WITH ANY CONFIDENCE, FOR
THE LOWER DESERTS, BUT LATEST NBM FORECAST HAS LIGHT POPS (LESS THAN
20%) BEGINNING AS EARLY AS WEDNESDAY. FRIDAY STILL LOOKS LIKE THE
BETTER TIME PERIOD FOR RAIN CHANCES AND THIS IS REFLECTED IN THE POP
FORECAST, WITH CLOSER TO 20-30%. INEVITABLY A STRONG TROUGH WOULD
BRING STRONGER WINDS TO THE REGION AND LATEST GLOBAL MODELS ARE
POINTING TO THE WEDNESDAY TIMEFRAME FOR THE BREEZIEST CONDITIONS. AS
FOR TEMPERATURES LATER NEXT WEEK, THE IQR OF THE NBM HAS NARROWED A
LITTLE BIT (A DELTA OF AROUND 10 DEGREES), WITH THE LOWER DESERT
HIGH TEMPERATURE RANGE AROUND LOW-70S TO LOW-80S. SOLACE CAN AT
LEAST BE TAKEN IN THAT THE NEXT SHOT AT 90 DEGREE TEMPERATURES MAY
NOT COME UNTIL CLOSER TO MIDDLE-APRIL...IF YOU ARE NOT A FAN OF 90+
DEGREES THAT IS.
AVIATION
UPDATED AT 0517Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
CURRENT WESTERLY WINDS WILL BECOME EASTERLY/SOUTHEASTERLY OVER THE
NEXT FEW HOURS, WITH SPEEDS GENERALLY AOB 10 KT. WINDS WILL THEN
GO BACK WESTERLY BY MID/LATE TOMORROW MORNING (AROUND 16-17Z).
SOME OCCASIONAL GUSTS INTO THE UPPER TEENS WILL ONCE AGAIN BE
POSSIBLE TOMORROW AFTERNOON. THICKER HIGH CLOUD DECKS WILL THIN BY
TOMORROW AFTERNOON.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
STRONG, GUSTY WINDS AT KIPL WILL BE THE PRIMARY WEATHER ISSUE
THROUGH SATURDAY EVENING UNDER PERIODS OF HIGH CIRRUS DECKS.
WESTERLY GUSTS AROUND 25-30 KT WILL BE COMMON AT KIPL THROUGH THE
OVERNIGHT PERIOD BEFORE DECOUPLING AROUND SUNRISE. WESTERLY GUSTS
AROUND 25 KT ARE AGAIN EXPECTED TOMORROW EVENING AT KIPL. AT KBLH,
SPEEDS WILL BE LIGHTER, GENERALLY AOB 10 KT, WITH S/SW DIRECTIONS
PREVAILING WITH THE POTENTIAL FOR SOME VARIABILITY DURING THE
MORNING HOURS.
FIRE WEATHER
CONTINUED DRY AND BREEZY CONDITIONS ARE EXPECTED TO PERSIST THROUGH
THIS WEEKEND, RESULTING IN PERIODS OF MARGINALLY ELEVATED FIRE
WEATHER. THE STRONGEST WINDS UP TO 25-35 MPH WILL RESIDE ACROSS THE
WESTERN DISTRICTS AND HIGHER TERRAIN OF MARICOPA AND GILA COUNTIES.
MINIMUM RELATIVE HUMIDITY IS EXPECTED TO RANGE FROM 15-20% EACH
AFTERNOON AND OVERNIGHT RECOVERIES SHOULD REMAIN FAIR UP TO 40-50%.
THERE WILL BE A SLOW IMPROVEMENT IN MOISTURE LEVELS BY THE MIDDLE TO
LATTER PORTIONS OF NEXT WEEK AS A POTENTIAL STRONGER WEATHER SYSTEM
ARRIVES. THERE IS STILL A LOT OF UNCERTAINTY WHETHER ANY MEANINGFUL
PRECIPITATION WILL ACCOMPANY THIS SYSTEM, BUT CHANCES FOR ANY
WETTING RAINFALL LOOKS VERY LOW AT THIS TIME.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...WIND ADVISORY UNTIL 5 AM PDT SATURDAY FOR CAZ562.
DISCUSSION...BENEDICT
AVIATION...BERISLAVICH/18
FIRE WEATHER...SALERNO
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