062  
FXUS65 KPSR 152350  
AFDPSR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PHOENIX AZ  
450 PM MST SAT FEB 15 2025  
   
UPDATE  
 
UPDATED AVIATION SECTION FOR 00Z 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 2350Z.  
 
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:  
 
EXPECT INCREASING CIRRUS TONIGHT WITH CEILINGS REMAINING AOA FL200  
THROUGH THE TAF PERIOD AS A WEATHER SYSTEM PASSES WELL TO THE  
NORTH. WESTERLY SURFACE WINDS WILL REMAIN LIGHT (BELOW 10KTS)  
BEFORE TRANSITIONING TO FAMILIAR NOCTURNAL PATTERNS THIS EVENING  
(DOWNVALLEY/DRAINAGE FAVORING EASTERLY COMPONENT). 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 (FAVORING NORTHERLY  
COMPONENT).  
 
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:  
 
EXPECT INCREASING CIRRUS TONIGHT WITH CEILINGS REMAINING AOA FL200  
THROUGH THE TAF PERIOD AS A WEATHER SYSTEM PASSES WELL TO THE  
NORTH. NORTHERLY SURFACE WINDS WILL WEAKEN THIS EVENING BEFORE  
TRANSITIONING TO FAMILIAR NOCTURNAL PATTERNS THIS EVENING  
(WESTERLY AT KIPL; NORTHWESTERLY AT KBLH). DURING THE AFTERNOON,  
ANTICIPATE LIGHT NORTHERLY WINDS (AOB 8KTS) TO RESUME AT KIPL WITH  
NORTHEASTERLY DIRECTIONS FAVORED AT KBLH.  
 
 
   
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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