400
FXUS65 KPSR 202310
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
410 PM MST MON APR 20 2026
UPDATE
UPDATED AVIATION.
KEY MESSAGES
- 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 THE 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 HEIGHT 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 2310Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
LOCALLY GUSTY WINDS AND AN EXTENDED PERIOD OF A SOUTHERLY CROSS
RUNWAY WIND EARLY TUESDAY AFTERNOON WILL BE THE MAIN WEATHER ISSUES
UNDER OCCASIONAL THICK HIGH CIRRUS DECKS. CONFIDENCE IS GOOD THAT
W/SW WINDS WILL PREVAIL SOMEWHAT LONGER INTO THE EVENING/OVERNIGHT
VERSUS USUAL TIMING WITH A CHANCE OF MID EVENING GUSTS NEARING 20KT.
AFTER THE TYPICAL MORNING EAST WINDS, AN EXTENDED PERIOD OF SOUTH
CROSS RUNWAY WINDS WITH SPEEDS IN EXCESS OF 10KT WILL BE LIKELY
BEFORE VEERING SW MID/LATE AFTERNOON. ANOTHER ROUND OF GUSTS NEAR
20KT WILL BE POSSIBLE AROUND SUNSET TUESDAY.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
STRENGTHENING WIND GUSTS TUESDAY AFTERNOON/EVENING WILL BE THE
PRIMARY WEATHER ISSUE UNDER BRIEF PERIODS OF THICKER HIGH CIRRUS
DECKS. CONFIDENCE IS GOOD THAT WINDS WILL SWITCH TO A WESTERLY
COMPONENT AT KIPL AND REMAIN IN PLACE THROUGH TUESDAY WHILE
SOUTHERLY WINDS WILL BE PREFERRED AT KBLH. GUSTS 20-25KT WILL
MATERIALIZE TUESDAY AFTERNOON WITH SPEEDS LIKELY STRENGTHENING
FURTHER AT KIPL TUESDAY EVENING.
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...18
FIRE WEATHER...RYAN/SALERNO
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