374
FXUS65 KPSR 202103
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
203 PM MST MON APR 20 2026
KEY MESSAGES
- A BROAD RIDGE OF HIGH PRESSURE ENCOMPASSING THE DESERT SOUTHWEST
WILL ALLOW TEMPERATURES TO HOVER AROUND 5 TO 10 DEGREES ABOVE
DAILY NORMALS THROUGH TUESDAY.
- A WIND ADVISORY HAS BEEN ISSUED FOR SW IMPERIAL VALLEY STARTING
TUESDAY 3 PM THROUGH WEDNESDAY 8 AM.
- A WEATHER SYSTEM PASSING NORTH OF THE REGION WILL RESULT IN
PERIODS OF BREEZY TO LOCALLY WINDY CONDITIONS AND COOLER
TEMPERATURES DURING THE LATTER HALF OF THIS WEEK.
SHORT TERM /TODAY THROUGH TUESDAY/
LATEST MID-LVL WV IMAGERY AND 500 MB STREAMLINE ANALYSIS SHOWS THE
THE UPPER LEVEL RIDGE SHIFTING EASTWARDS INTO THE FOUR CORNERS
REGION, WHILE A DEEP CUT-OFF LOW CONTINUES TO APPROACH NORTHERN
CALIFORNIA. THE DESERT SW WILL CONTINUE TO BE INFLUENCED BY POSITIVE
HEIGHT ANOMALIES TODAY WITH H5 HEIGHTS BETWEEN 577-580 DAM, DRIVING
TEMPERATURES TO ABOVE NORMAL FOR THIS TIME OF YEAR. EXPECT AFTERNOON
HIGHS TODAY IN THE MID TO UPPER 90S ACROSS THE LOWER DESERTS WHILE
THE HIGHER TERRAIN AREAS WILL GENERALLY BE IN THE MID 80S. HOWEVER,
WITHIN THIS UPPER LEVEL RIDGE, A WEAK SHORTWAVE LOOKS TO PASS
THROUGH THE REGION THIS AFTERNOON/EVENING PROVIDING ENOUGH MOISTURE
AND LIFT FOR THE DEVELOPMENT OF ISOLATED SHOWERS AND STORMS OVER
NORTHERN ARIZONA. WHILE MOST OF THE ACTIVITY IS EXPECTED TO BE ALONG
THE MOGOLLON RIM, THERE IS A NON-ZERO (~5%) CHANCE OF STORMS
DEVELOPING OVER SOUTHERN GILA COUNTY LATE THIS AFTERNOON.
TUESDAY'S TEMPERATURES WILL BE MUCH OF THE SAME, WITH HIGHS ACROSS
SC AND EASTERN ARIZONA RELATIVELY UNCHANGED UNDER THE DEPARTING
RIDGE, WHILE OUT WEST TEMPERATURES WILL BE 1-2 DEGREES COOLER AS THE
CUT-OFF LOW BEGINS TO MOVE ONSHORE OF NORTHERN CALIFORNIA. AHEAD OF
THIS FEATURE, SOUTHWESTERLY FLOW WILL CONTINUE TO STRENGTHEN OVER
THE WESTERN HALF OF OUR CWA CAUSING WIDESPREAD BREEZY TO LOCALLY
WINDY CONDITIONS STARTING TUESDAY AFTERNOON. DUE TO THIS A WIND
ADVISORY HAS BEEN ISSUED FOR THE SW PORTION OF IMPERIAL VALLEY
STARTING TUESDAY 3 PM THROUGH WEDNESDAY 8 AM. DURING THIS TIME THE
AFFECTED AREA CAN EXPECT WINDS BETWEEN 25-35 MPH AND WIND GUSTS UP
TO 55 MPH ARE POSSIBLE. MEANWHILE THE REMAINING PORTIONS OF IMPERIAL
AND RIVERSIDE COUNTIES CAN EXPECT GUSTS BETWEEN 20-30 MPH AND IN
SOUTH-CENTRAL AND EASTERN ARIZONA GUSTS BETWEEN 10-15 MPH WILL BE
COMMON THROUGHOUT TUESDAY AFTERNOON.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
DETERMINISTIC AND ENSEMBLE GUIDANCE ARE IN GOOD AGREEMENT THAT
THE CUTOFF LOW OVER THE WEST COAST WILL TRANSITION TO AN OPEN WAVE
AND PROGRESS THROUGH THE INTERMOUNTAIN WEST FROM WEDNESDAY INTO
THURSDAY. NEGATIVE HGHT ANOMALIES FROM THE PASSING SYSTEM WILL
RESULT IN COOLER TEMPERATURES (LIKELY CLOSER TO SEASONAL LEVELS,
IN THE MID 80S ACROSS THE LOWER DESERTS) BEGINNING ON WEDNESDAY.
PERIODS OF BREEZY TO LOCALLY WINDY CONDITIONS CAN ALSO BE
ANTICIPATED ACROSS THE ENTIRE FORECAST AREA DUE TO H7-H5 GRADIENT
REMAINING COMPACT. THE MOST WIDESPREAD BREEZY CONDITIONS LOOK TO
BE ON WEDNESDAY AND THEN STRONGER WINDS WILL TRANSITION TO THE
HIGH TERRAIN OF EASTERN AZ ON THURSDAY AS THE TROUGH AXIS PASSES
THROUGH THE REGION. QUASI-ZONAL FLOW ALOFT WILL RETURN BY FRIDAY
AND INTO NEXT WEEKEND AHEAD OF ANOTHER POTENTIAL SHORTWAVE TROUGH.
THIS WILL ALLOW FOR A TEMPORARY BOOST IN TEMPERATURES FRIDAY AND
SATURDAY BEFORE THE NEXT WEATHER SYSTEM AND SUBSEQUENT COOLER
TEMPERATURES ARRIVE ON SUNDAY.
AVIATION
UPDATED AT 1725Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR AVIATION CONCERNS ARE EXPECTED DURING THE TAF PERIOD.
WINDS WILL FOLLOW FAMILIAR DIURNAL TRENDS, THOUGH IT WILL TAKE
LONGER THAN USUAL TO ACHIEVE THE AFTERNOON/EVENING W'RLY SHIFT,
ESPECIALLY AT KPHX WHERE A S'RLY COMPONENT MAY BE OBSERVED FOR
SEVERAL HOURS. A BRIEF WINDOW OF MARGINAL BREEZINESS IS SHOWN
BETWEEN 04-06Z THIS EVENING WITH GUSTS AROUND 15-20KT, WITH THOSE
HIGHER READINGS FAVORED AT SKY HARBOR. FEW MID-LEVEL CLOUDS OVER
THE HIGH TERRAIN WILL BE PRESENT OVER THE NEXT SEVERAL HOURS
BEFORE SCT-BKN HIGH CLOUDS MOVE IN OVERNIGHT.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED DURING THE NEXT 24 HOURS.
KIPL WILL FOLLOW FAMILIAR SPRING TIME DIURNAL TRENDS WHILE KBLH
WILL SEE GENERALLY S'RLY WINDS WITH SOME AFTERNOON BREEZES NEAR
20-25KT. CLEAR SKIES THIS AFTERNOON WILL GIVE WAY TO SCT-BKN HIGH
CLOUDS TONIGHT.
FIRE WEATHER
A VERY PROGRESSIVE PATTERN WITH MULTIPLE DRY WEATHER SYSTEMS
PASSING NORTH OF THE REGION WILL RESULT IN BREEZY CONDITIONS AND
PERIODS OF ELEVATED FIRE WEATHER THROUGHOUT THIS WEEK. THE
BEGINNING OF THE WEEK WILL SEE ABOVE NORMAL TEMPERATURES AND
BREEZY CONDITIONS COMBINED WITH MIN RH VALUES OF 8-15% WHICH WILL
RESULT IN WIDESPREAD ELEVATED FIRE WEATHER CONDITIONS. THIS WILL
ESPECIALLY BE SEEN ACROSS THE WESTERN DISTRICTS ON TUESDAY
AFTERNOON WHERE A WIND ADVISORY HAS BEEN ISSUED FOR SW IMPERIAL
VALLEY WHERE GUSTS UP TO 55 MPH WILL BE POSSIBLE. BREEZY AND DRY
CONDITIONS WILL CARRY THROUGH THE REST OF THIS WEEK AND INTO THIS
WEEKEND WITH RELATIVE HUMIDITY REMAINING AT OR BELOW 15% EACH
AFTERNOON. OVERNIGHT RECOVERIES WILL ALSO VARY THROUGH THE WEEK,
BUT REMAIN MOSTLY IN THE 30-50% RANGE.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...WIND ADVISORY FROM 3 PM TUESDAY TO 8 AM PDT WEDNESDAY FOR CAZ562.
SHORT TERM..RYAN
LONG TERM...SALERNO
AVIATION...RW
FIRE WEATHER...RYAN/SALERNO
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