100
FXUS65 KPSR 201044
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
344 AM 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 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 REVEALS
A BROAD RIDGE ENCOMPASSING MUCH OF THE INTERMOUNTAIN WEST AND
4-CORNERS REGION. MEANWHILE, A DEEP CUTOFF LOW IS APPROACHING THE
WEST COAST, BRINING ABUNDANT MOISTURE AND CLOUD COVER TO THE PAC
NW AND NORCAL. OUR REGION WILL REMAIN UNDER THE INFLUENCE OF THE
RIDGE TODAY AND TO A LESSER EXTENT ON TUESDAY WHICH WILL KEEP
TEMPERATURES IN AN ABOVE AVERAGE CATEGORY. A WEAK DISTURBANCE ON
THE WESTERN PERIPHERY OF THE RIDGE DID BRING EXTENSIVE CLOUD COVER
AND SOME VIRGA THROUGH THE AREA YESTERDAY, BUT THIS INITIAL
SHORTWAVE IS DEPARTING TO THE NORTH AND CLOUDS ARE EXPECTED TO
CLEAR OUT THIS MORNING. UNDER PRESENCES OF THE RIDGE TODAY, H8
TEMPERATURES WILL AGAIN REACH 18-20C THIS AFTERNOON. THIS WILL
TRANSLATE TO ANOTHER ROUND OF HIGHS IN THE MID 90S ACROSS THE
LOWER DESERTS AND LOW TO MID 80S IN THE HIGH TERRAIN WHICH IS
AROUND 8-10 DEGREES ABOVE NORMAL FOR LATE APRIL. ANOTHER WEAK
SHORTWAVE IN SOUTHWESTERLY FLOW WILL TRANSLATE THROUGH AZ LATE
TODAY AND WILL PROVIDE ENOUGH MID-LVL MOISTURE AND LIFT TO
GENERATE SHOWERS AND EVEN A FEW ISOLD STORMS OVER N ARIZONA. THERE
IS AROUND A 10% CHANCE OF AN ISOLATED SHOWER OR STORM OVER S GILA
COUNTY THIS AFTERNOON, HOWEVER THE MAIN FOCUS WILL BE FARTHER N
ALONG THE MOGOLLON RIM. ELSEWHERE, TRANQUIL WEATHER CONDITIONS
WILL EXIST WITH MUCH LIGHTER WINDS ACROSS SOUTHCENTRAL AZ.
ON TUESDAY, THE AFOREMENTIONED CUTOFF LOW OFF THE COAST OF NORCAL
WILL BEGIN TO MOVE ONSHORE. AHEAD OF THIS FEATURE, SOUTHWESTERLY
FLOW WILL CONTINUE TO STRENGTHEN OVER THE WESTERN HALF OF OUR
FORECAST AREA. THE TIGHTENING OF THE H7-H5 GRADIENT WILL LEAD TO
BREEZY CONDITIONS, ESPECIALLY ACROSS SE CALIFORNIA AND SW ARIZONA
WHERE GUSTS COULD REACH 30-35 MPH AT TIMES. WINDS WILL BE
STRONGEST OVER THE HIGHER TERRAIN AND AT RIDGETOP LVL, ESPECIALLY
IN SW IMPERIAL COUNTY WHERE LOW END ADVISORY WINDS WILL BE
POSSIBLE. AS THE UPPER-LVL TROUGH CONTINUES TO APPROACH FROM THE
WEST, 500 MB HGHTS WILL LOWER TO AROUND 573-575 DAM FOR AREAS
ALONG AND WEST OF THE CO RIVER VALLEY WHERE HIGHS WILL BE SLIGHTLY
COOLER IN THE UPPER 80S AND LOW 90S TUESDAY AFTERNOON. AREAS
FARTHER EAST INCLUDING THE LOWER DESERTS OF SOUTHCENTRAL AZ WILL
STILL BE UNDER THE INFLUENCE OF THE DEPARTING UPPER RIDGE AND THUS
HIGHS WILL BE WARMER IN THE LOW TO MID 90S.
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 0500Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
WINDS WILL BE THE PRIMARY FORECAST ISSUE THROUGH MONDAY NIGHT AS
THICKER MID/HIGH CIGS CLEAR BY MONDAY MORNING. FORECAST CONFIDENCE
INCREASES LATE TONIGHT AND MONDAY AS WIND DIRECTIONS EVENTUALLY
SWITCH TO EASTERLY, THEN OBTAIN THE TRADITIONAL AFTERNOON/EVENING
WEST COMPONENT. SOME ENHANCED GUSTS MAY ENTER THE METRO MONDAY
EVENING CAUSING THE NOCTURNAL SWITCH BACK TO EASTERLY TO BECOME
DELAYED MUCH LATER INTO MONDAY NIGHT/TUESDAY MORNING.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO SIGNIFICANT WEATHER ISSUES WILL EXIST THROUGH MONDAY NIGHT UNDER
MOSTLY CLEAR SKIES. WINDS WILL GENERALLY OSCILLATE BETWEEN SE AND SW
AT KIPL WHILE FAVORING A SOUTHERLY DIRECTION AT KBLH. INCREASED
GUSTINESS OVER 20KT WILL BECOME MORE COMMON MONDAY LATE
AFTERNOON/EVENING, ESPECIALLY AT KBLH.
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. DURING THE
FIRST HALF OF THE WEEK, ABOVE NORMAL TEMPERATURES AND BREEZY
CONDITIONS COMBINED WITH MIN RH VALUES OF 8-15% WILL RESULT IN
WIDESPREAD ELEVATED FIRE WEATHER CONDITIONS, ESPECIALLY ACROSS THE
WESTERN DISTRICTS ON TUESDAY AND THE HIGHER TERRAIN OF SOUTHCENTRAL
AZ ON WEDNESDAY WHERE GUSTS UP 20-30 MPH WILL BE COMMON. 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...NONE.
SHORT TERM..SALERNO
LONG TERM...SALERNO
AVIATION...18
FIRE WEATHER...SALERNO
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