206
FXUS65 KPSR 180529
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1029 PM MST MON FEB 17 2025
UPDATE
UPDATED AVIATION DISCUSSION.
SYNOPSIS
DRY AND TRANQUIL WEATHER WILL BE COMMON THROUGH THE WORKWEEK, WITH
ABOVE NORMAL TEMPERATURES ACROSS THE REGION. EXPECT LOCALLY BREEZY
CONDITIONS AS A FEW WEAK WEATHER SYSTEMS MOVE THROUGH NORTHERN
ARIZONA DURING THE WEEK. AS HIGH PRESSURE BUILDS OVER THE WEEKEND,
TEMPERATURES WILL WARM FURTHER AND NEAR RECORD DAILY HIGHS BY EARLY
NEXT WEEK.
DISCUSSION
CURRENT MID-LEVEL WV IMAGERY DEPICTS A LOW AMPLITUDE SHORTWAVE
TROUGH MOVING OVER NORTHEASTERN AZ AS IT CONTINUES SLIDING
SOUTHEASTWARD TOWARDS THE FOUR CORNERS. PRESSURE GRADIENTS ALOFT
HAVE TIGHTENED AHEAD OF THIS SYSTEM, AND COUPLED WITH DAYTIME
MIXING, GUSTS TO 20-35 MPH HAVE DEVELOPED OVER THE NORTHERN/CENTRAL
AZ HIGH TERRAIN SO FAR THIS AFTERNOON. WITHIN THE FORECAST AREA, THE
STRONGEST WINDS WILL BE VERY LOCALIZED OVER THE FAR SW CORNER OF
IMPERIAL COUNTY, WHERE HREF PROBABILITIES OF GUSTS IN EXCESS OF 40
MPH ARE AROUND 80-90%, PARTICULARLY THIS EVENING THROUGH EARLY
TUESDAY MORNING (BEFORE SUNRISE). EXPECT SOME LINGERING BREEZINESS
TUESDAY MID MORNING INTO THE AFTERNOON FOR PORTIONS OF SE CA AND IN
THE VICINITY OF THE LOWER COLORADO RIVER VALLEY. AFTERNOON HIGHS ARE
ONLY EXPECTED TO REACH THE MIDDLE 70S ACROSS THE SOUTH-CENTRAL AZ
LOWER DESERTS DUE TO PERSISTENT CLOUD COVER AND CLOSER TO 80F
FURTHER WEST TODAY, AND DESPITE HEIGHTS ALOFT BEING SOMEWHAT LOWERED
BY THE SHORTWAVE, FORECAST HIGHS ARE GENERALLY ONLY A DEGREE OR TWO
COOLER TUESDAY.
THE FORECAST REMAINS ON TRACK FOR THE REMAINDER OF THE WORKWEEK,
WITH QUASI-ZONAL TO NORTHWEST FLOW ALOFT BEING MAINTAINED OVER THE
SOUTHWEST US. ANOTHER LOW AMPLITUDE SHORTWAVE TROUGH IS ADVERTISED
BY ENSEMBLES DIVING SOUTH FROM THE GREAT BASIN INTO NORTHERN AZ
LIKELY BY THURSDAY NIGHT. ONCE AGAIN, IMPACTS WILL BE MINIMAL FROM
THIS SECOND SHORTWAVE, THOUGH ITS TRAJECTORY WILL BE FAVORABLE FOR
SENDING A FRONT SOUTHWARD DOWN THE COLORADO RIVER VALLEY. GUSTY
WINDS WITH THIS SECOND SYSTEM COMBINED WITH ANY REMAINING DRY FUELS
AND LOW HUMIDITIES COULD LEAD TO LOCALLY ELEVATED FIRE WEATHER
CONDITIONS ALONG THE LOWER COLORADO RIVER VALLEY. AS A RESULT OF
TRANSIENT RIDGING MIDWEEK AND THE SECOND SHORTWAVE LATE THIS WEEK,
TEMPERATURES WILL FLUCTUATE BY A FEW DEGREES DAY TO DAY, BUT
OVERALL, LOWER DESERT HIGHS WILL BE FAIRLY STABLE BETWEEN THE MIDDLE
70S AND AROUND 80F WEDNESDAY THROUGH EARLY THIS WEEKEND (AROUND 4F-
8F ABOVE NORMAL.) OVER THE WEEKEND, A WARMING TREND WILL COMMENCE AS
EXPANSIVE POSITIVE HEIGHT ANOMALIES BUILD OVER MUCH OF THE
WESTERN US. GUIDANCE REMAINS IN REMARKABLE AGREEMENT EVEN INTO THE
MIDDLE OF NEXT WEEK THAT H5 HEIGHTS OVER THE FORECAST AREA WILL
NEAR OR EXCEED 582 DM, CLOSE TO THE 98TH PERCENTILE OF CFSR
CLIMATOLOGY FOR THIS TIME OF YEAR, LEADING TO WELL-ABOVE NORMAL
TEMPERATURES. LATEST NBM FORECAST HIGHS FOR NEXT MONDAY ARE IN THE
MIDDLE TO UPPER 80S ACROSS THE LOWER DESERTS, WHICH IS 10F-15F
ABOVE NORMAL. THESE WELL-ABOVE NORMAL TEMPERATURES SHOULD BE
COMMON THROUGH THE MIDDLE OF NEXT WEEK, WITH A DECENT CHANCE
(40-60%) OF SEEING OUR FIRST 90 DEGREE DAY OF THE YEAR IN PHOENIX.
AVIATION
UPDATED AT 0528Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT; AND
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO AVIATION WEATHER CONCERNS ARE EXPECTED THROUGH THE TAF PERIOD
UNDER PASSING HIGH CIRRUS DECKS. WINDS WILL FOLLOW LIGHT, DIURNAL
TENDENCIES, WITH SPEEDS MOSTLY BELOW 10 KTS, WHILE EXTENDED
PERIODS OF CALM OR VARIABLE CONDITIONS MAY OCCUR DURING THE
DIURNAL TRANSITION PERIODS. SOME BREEZY NORTHERLY WINDS WILL BE
POSSIBLE AT KBLH STARTING AROUND 17-18Z WITH A FEW GUSTS UPWARDS
OF 15-20 KTS THROUGH THE AFTERNOON.
FIRE WEATHER
DRY CONDITIONS WITH DAILY MINRH'S RANGING IN THE MID TO UPPER TEENS
REGION-WIDE WILL PERSIST THROUGH THIS WEEK. WINDS WILL GENERALLY
FOLLOW TYPICAL DIURNAL TENDENCIES EACH DAY THROUGH MONDAY, WITH THE
NEXT ROUND OF BREEZY CONDITIONS DEVELOPING ACROSS THE WESTERN
DISTRICTS ON TUESDAY. TEMPERATURES WILL REMAIN ABOVE NORMAL AROUND 5-
10 DEGREES THROUGH THIS WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
DISCUSSION...WHITTOCK
AVIATION...SMITH
FIRE WEATHER...YOUNG/RW
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