065
FXUS65 KPSR 160524
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1024 PM MST SAT FEB 15 2025
UPDATE
UPDATED AVIATION SECTION FOR 06Z TAFS.
SYNOPSIS
TEMPERATURES WARM TO ABOVE AVERAGE SUNDAY AND THROUGH NEXT WEEK.
EXPECT AFTERNOON HIGHS TO GENERALLY REACH THE MIDDLE SEVENTIES
SUNDAY ONWARD, UP TO AROUND EIGHTY DEGREES SOME DAYS NEXT WEEK FOR
THE TYPICALLY WARMER LOWER DESERT LOCALES. DRY AND OCCASIONALLY
BREEZY CONDITIONS ARE EXPECTED THROUGH THE NEXT WEEK.
DISCUSSION
THE FORECAST AREA REMAINS UNDER STRONG NORTHWEST FLOW ALOFT, WITH A
TRANSIENT UPPER LEVEL RIDGE APPARENT IN MID-LEVEL WV IMAGERY
SHIFTING ONSHORE ALONG THE WEST COAST. WITH DAYTIME HEATING/MIXING,
SOME LINGERING BREEZINESS HAS DEVELOPED (GUSTS TO 20-25 MPH) OVER
THE WIND PRONE AREAS OF THE WESTERN DESERTS, I.E., ALONG THE LOWER
COLORADO RIVER VALLEY AND PORTIONS OF SW AZ AND SE CA. ELSEWHERE,
THE REST OF TODAY WILL FEATURE RELATIVELY QUIESCENT CONDITIONS, WITH
AFTERNOON HIGHS REACHING NEAR THEIR NORMAL VALUES FOR THE DATE,
GENERALLY IN THE LOWER 70S FOR THE LOWER DESERTS. THE AFOREMENTIONED
TRANSIENT RIDGE SHIFTS OVERHEAD TONIGHT/SUNDAY, WITH NAEFS AND EPS
MEAN 700 MB TEMPERATURES REACHING JUST ABOVE THE 90TH PERCENTILE
OF CFSR CLIMATOLOGY FOR THIS TIME OF YEAR AT AROUND 5 DEG C.
DESPITE INCREASED HIGH CLOUDS SUNDAY (AS SHOWN IN HREF GUIDANCE),
THE ABNORMALLY WARM TEMPERATURES ALOFT ARE EXPECTED TO SUPPORT
AFTERNOON HIGHS REACHING SLIGHTLY ABOVE NORMAL, IN THE MIDDLE 70S
FOR THE TYPICALLY WARMER LOWER DESERT LOCALES. THE WARMING TREND
WILL CONTINUE INTO NEXT WEEK, THOUGH A FEW DISTURBANCES SHOULD
PREVENT HIGHS FROM REACHING MUCH ABOVE 80F THROUGH THE UPCOMING
WORKWEEK.
NORTHWEST TO QUASI-ZONAL FLOW ALOFT WILL BE MAINTAINED THROUGH THE
UPCOMING WORKWEEK OVER THE SOUTHWEST US, WITH A COUPLE UPPER LEVEL
LOWS MOVING THROUGH THE WESTERN CONUS. ONE SUCH UPPER LOW IS EVIDENT
IN SATELLITE IMAGERY OFF THE PACIFIC NORTHWEST COAST TODAY.
ENSEMBLES ARE IN EXCELLENT AGREEMENT THAT THIS FEATURE WILL MOVE
ONSHORE LATE THIS WEEKEND INTO EARLY NEXT WEEK, THEN DIVE
SOUTHEASTWARD, PASSING OVER THE FOUR CORNERS ON TUESDAY. SENSIBLE
WEATHER IMPACTS FROM THIS FIRST SYSTEM WILL INCLUDE BREEZY
CONDITIONS OVER AZ HIGH TERRAIN AND THE SW CORNER OF IMPERIAL COUNTY
MONDAY AFTERNOON/NIGHT, FOLLOWED LIKELY BY MORE WIDESPREAD BREEZY
CONDITIONS ACROSS THE WESTERN DESERTS ON TUESDAY AND HIGHS COOLING A
FEW DEGREES FROM THEIR FORECAST VALUES ON MONDAY (YET REMAINING
ABOVE NORMAL.) TEMPERATURE WILL REBOUND BACK TO 4F-8F ABOVE NORMAL
WITH ANOTHER TRANSIENT RIDGE BUILDING MIDWEEK. ANOTHER UPPER LOW
LOOKS TO MOVE THROUGH LATE WEEK, THOUGH POSITIVE H5 HEIGHT ANOMALIES
ARE SHOWN REMAINING IN PLACE WITH THIS SECOND SYSTEM, AND SO NBM
HIGHS REMAIN RELATIVELY STABLE.
WPC CLUSTER ANALYSIS REVEALS SURPRISINGLY GOOD AGREEMENT BETWEEN
ENSEMBLES EVEN 8-9 DAYS OUT. ALL CLUSTERS DEPICT A BROAD AREA OF
STRONG POSITIVE H5 HEIGHT ANOMALIES OVER THE EAST PACIFIC/ALONG
THE WEST COAST, WITH HEIGHTS POTENTIALLY IN EXCESS OF 582 DM OVER
THE FORECAST AREA. THIS WOULD SUPPORT FURTHER WARMING WELL INTO
THE 80S LATE NEXT WEEKEND AND INTO THE FOLLOWING WEEK, AS WELL AS
CONTINUED DRY CONDITIONS.
AVIATION
UPDATED AT 0524Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
EXPECT THICK CIRRUS CONTINUING THROUGH THE FORECAST PERIOD AS A
WEATHER SYSTEM PASSES WELL TO THE NORTH. THE TRANSITION TO LIGHT
DOWNVALLEY/DRAINAGE PATTERNS (FAVORING AN EASTERLY COMPONENT) HAVE
STARTED TO DEVELOP AND WILL BECOME ESTABLISHED EARLY IN THE TAF
PERIOD. DURING THE LATE MORNING SUNDAY THERE MAY BE A SHORT LIVED
PERIOD OF MINOR GUSTINESS (UP TO 15KTS) AT KPHX. ANTICIPATE LIGHT
AND VARIABLE WINDS DURING THE LATTER HALF OF THE AFTERNOON BEFORE
MORE COHERENT WESTERLY DIRECTIONS DEVELOP BY 01Z MONDAY (SUSTAINED
SPEEDS AOA 6KTS).
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
EXPECT THICK CIRRUS CONTINUING THROUGH THE FORECAST PERIOD AS A
WEATHER SYSTEM PASSES WELL TO THE NORTH. THE TRANSITION TO LIGHT
DOWNVALLEY/DRAINAGE PATTERNS HAS STARTED (WLY AT KIPL; N/NWLY AT
KBLH). DURING THE AFTERNOON, ANTICIPATE LIGHT NORTHERLY WINDS
(AOB 8KTS) TO RESUME AT KIPL WITH NORTHEASTERLY DIRECTIONS FAVORED
AT KBLH. THIS WILL BE FOLLOWED BY AN EVENING TRANSITION TO LIGHT
NOCTURNAL PATTERNS.
FIRE WEATHER
DRY CONDITIONS WILL PERSIST ACROSS THE REGION THROUGH NEXT WEEK.
MINRH'S RANGING FROM THE MID TO UPPER TEENS IN THE WESTERN DISTRICTS
TO 20-30% IN THE EASTERN DISTRICTS TODAY WILL DRY TO THE MID TO
UPPER TEENS REGION-WIDE THROUGH EARLY NEXT WEEK. WINDS WILL RETURN
TO MORE TYPICAL DIURNAL TENDENCIES GOING THROUGH THE WEEKEND, WITH
THE NEXT ROUND OF BREEZY CONDITIONS DEVELOPING ACROSS THE WESTERN
DISTRICTS ON TUESDAY.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
DISCUSSION...WHITTOCK
AVIATION...AJ
FIRE WEATHER...YOUNG
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