254
FXUS65 KPSR 012100
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
200 PM MST FRI MAY 1 2026
KEY MESSAGES
- BREEZY TO LOCALLY WINDY CONDITIONS ARE EXPECTED THIS WEEKEND,
ESPECIALLY SUNDAY AND LINGERING INTO EARLY NEXT WEEK, AS A LOW
PRESSURE SYSTEM MOVES INLAND ALONG THE CALIFORNIA COAST.
- LOWER DESERT HIGH TEMPERATURES IN THE MIDDLE NINETIES WILL BE
COMMON THROUGH THE WEEKEND, FOLLOWED BY A COOLDOWN INTO THE
UPPER SEVENTIES AND EIGHTIES DURING THE FIRST HALF OF NEXT WEEK.
SHORT TERM /TODAY THROUGH SUNDAY/
SEVERAL FEATURES ARE APPARENT IN EARLY AFTERNOON WATER VAPOR IMAGERY
RELEVANT TO THE OVERALL PATTERN THIS WEEKEND INTO EARLY NEXT WEEK:
1) A MIDLEVEL RIDGE PIVOTING OVER THE WESTERN US WITH HEIGHTS
BUILDING INTO THE FORECAST AREA FROM THE SOUTHWEST, "SQUISHED" IN
BETWEEN 2) A LONGWAVE, NEARLY STATIONARY TROUGH DOWNSTREAM OVER MUCH
OF THE CENTRAL AND EASTERN CONUS AND 3) A TROUGH OFF THE PACIFIC
NORTHWEST COAST, WHICH IS EXPECTED TO DIG SOUTHWARD AND DEEPEN JUST
OFFSHORE OVER THE WEEKEND, EVENTUALLY FORMING A CUTOFF LOW. TODAY,
THE DEPARTING SHORTWAVE WHICH BROUGHT SHOWERS AND STORMS TO
SOUTHEAST AZ YESTERDAY WILL JOIN WITH THE LONGWAVE TROUGH, WHILE A
SECOND DISTURBANCE SLIDES SOUTHWARD (CURRENTLY OVER UTAH) AND THEN
PROGRESSES INTO NM TONIGHT. THE MAIN IMPACT FROM THIS DISTURBANCE
DIVING SOUTHWARD WILL BE SOME INCREASED BREEZINESS ACROSS PORTIONS
OF THE REGION THROUGH THE AFTERNOON, AND IT WILL LIKELY ALSO AID IN
SQUEEZING OUT LINGERING MOISTURE, WITH SOME WEAK CONVECTIVE SHOWERS
OVER THE FAR EASTERN AZ HIGH TERRAIN ALREADY OBSERVED. OTHERWISE,
THE INFLUENCE OF THE BUILDING HEIGHTS ALOFT WILL PREDOMINATE, WITH
LOWER DESERT HIGHS LIKELY PEAKING IN THE MIDDLE 90S ACROSS SE CA AND
SW AZ THIS AFTERNOON, THEN AREAWIDE BY SATURDAY.
IN A FAMILIAR SETUP TO WHAT WE'VE SEEN ON SEVERAL OCCASIONS THIS
SPRING, SHORTWAVE ENERGY DEPARTS THE SOUTHWEST US TO THE EAST,
UPPER LEVEL RIDGING BUILDS FROM THE WEST, AND SURFACE HIGH
PRESSURE DEVELOP OVER THE SOUTHERN PLAINS, LEADING AN EASTERLY
GRADIENT WIND TO DEVELOP OVERNIGHT TONIGHT AND AGAIN TO A LESSER
EXTENT SATURDAY NIGHT. THE RESULT WILL BE A SURGE OF BREEZY
EASTERLY WINDS ACROSS THE AZ LOWER ELEVATIONS SHORTLY AFTER
SUNRISE, WITH STRONGER GUSTS (LOCALLY UPWARDS OF 30-35 MPH)
CONFINED TO THE HIGHER TERRAIN EAST OF PHOENIX.
ON SUNDAY, THE INFLUENCE OF THE CUTOFF LOW OFF THE CA COAST WILL
BE FELT AS IT DRAWS NEARER. GLOBAL GUIDANCE HAS TRENDED THIS
SYSTEM SLOWER OVER THE LAST DAY OR TWO, SO NOW HEIGHT PACKING WILL
LIKELY BE MAXIMIZED SUNDAY NIGHT INTO MONDAY OVER THE FORECAST
AREA. REGARDLESS, ANTICIPATE WIDESPREAD BREEZY CONDITIONS WITH
GUSTS COMMONLY REACHING 20-35 MPH AREAWIDE BY SUNDAY AFTERNOON
INTO THE EVENING. LOCALLY STRONGER GUSTS ARE ANTICIPATED FOR THE
TYPICALLY PRONE PORTIONS OF SE CA (SOUTHWEST CORNER OF IMPERIAL
COUNTY), WHERE A WIND ADVISORY WILL LIKELY BE NEEDED BEGINNING
SUNDAY EVENING.
LONG TERM /MONDAY THROUGH THURSDAY/
BY EARLY NEXT WEEK THE AFOREMENTIONED CLOSED LOW WILL BEGIN TO MOVE
INLAND AND MIGRATE SOUTHEASTWARDS DOWN THE STATE OF CALIFORNIA
BEFORE MOVING INTO THE DESERT SW. AS A RESULT, TEMPERATURES WILL
COOL INTO A 5 TO 10 DEGREE BELOW NORMAL RANGE, TRANSLATING TO
LOWER DESERT HIGHS IN THE MIDDLE 80S ON MONDAY AND A BIT COOLER
TUESDAY, IN THE UPPER 70S TO LOWER 80S. BREEZY CONDITIONS WILL
LINGER FOR A COUPLE DAYS. BY MID WEEK, CONFIDENCE IN THE FORECAST
DECREASES CONSIDERABLY WITH CLUSTER ANALYSIS SHOWING DIFFERENCES
IN WHEN THIS CLOSED LOW WILL EXIT THE REGION OR IF IT SIMPLY
WEAKENS AS POSITIVE HEIGHT ANOMALIES BUILD FROM THE PACIFIC
NORTHWEST. THE MODEL CONSENSUS, HOWEVER, POINT TOWARDS CONDITIONS
REMAINING DRY AND A WARMING TREND STARTING MID TO LATE NEXT WEEK.
AVIATION
UPDATED AT 1725Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR WEATHER ISSUES WILL EXIST THROUGH SATURDAY AFTERNOON UNDER
CLEAR SKIES. CONFIDENCE IS GOOD THAT WINDS WILL SHIFT TO WESTERLY
EARLIER THAN NORMAL TODAY WITH OCCASIONAL GUSTS UP TO 15KT. AFTER
THE TYPICAL SHIFT TO EAST OVERNIGHT, SOME ENHANCEMENT IN SPEEDS AND
GUSTINESS WILL BE POSSIBLE SATURDAY MID/LATE MORNING, THOUGH
CONFIDENCE IN GUST MAGNITUDE AND DURATION IS LOW.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO WEATHER ISSUES WILL EXIST THROUGH SATURDAY AFTERNOON UNDER CLEAR
SKIES. WHILE PROLONGED PERIODS OF LIGHT AND VARIABLE WINDS WILL BE
COMMON, A PREDOMINANT LIGHT WESTERLY FETCH WILL BE FAVORED AT KIPL
THIS EVENING AND OVERNIGHT, WHILE A NORTHERLY DIRECTION WILL
EVENTUALLY BE FAVORED AT KBLH.
FIRE WEATHER
DRY CONDITIONS AND SLIGHTLY ABOVE NORMAL TEMPERATURES WILL BE
OBSERVED THROUGH THE WEEKEND. A LOW PRESSURE SYSTEM WILL GRADUALLY
APPROACH THE CA COAST LATE THIS WEEKEND, RESULTING IN WIDESPREAD
BREEZY TO LOCALLY WINDY CONDITIONS INTO EARLY NEXT WEEK AND
TEMPERATURES COOLING INTO A BELOW NORMAL CATEGORY MONDAY-TUESDAY.
GUSTY AFTERNOON WINDS COMBINED WITH LOW HUMIDITIES WILL LIKELY
PRODUCE ELEVATED FIRE WEATHER CONDITIONS SUNDAY FOR PORTIONS OF
THE WESTERN DISTRICTS INCLUDING THE LOWER COLORADO RIVER VALLEY.
AFTERNOON MINRHS IN A 8-15% RANGE WILL BE COMMON THROUGH SATURDAY,
INCREASING SLIGHTLY INTO A 10-20% RANGE SUNDAY AND 15-25% RANGE
EARLY NEXT WEEK. OVERNIGHT RECOVERIES WILL DECREASE AREAWIDE
TONIGHT INTO A 20-50% RANGE AND AGAIN SATURDAY NIGHT.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...WHITTOCK
LONG TERM...RYAN/WHITTOCK
AVIATION...18
FIRE WEATHER...WHITTOCK
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