179  
FXUS65 KPSR 102109  
AFDPSR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PHOENIX AZ  
209 PM MST SAT MAY 10 2025  
 

 
   
SYNOPSIS
 
 
HOTTEST TEMPERATURES SO FAR THIS YEAR ARE EXPECTED TODAY AND  
TOMORROW, WITH HIGHS ACROSS THE LOWER DESERT RANGING FROM 100-108.  
THIS IS DUE TO HIGH PRESSURE ALOFT FULLY SETTLING OVER THE REGION.  
WIDESPREAD MODERATE HEATRISK TO LOCALIZED MAJOR HEATRISK WILL  
LAST THROUGH THE WEEKEND BECAUSE OF THESE TEMPERATURES. DAILY  
BREEZY CONDITIONS HAVE DEVELOPED THIS MORNING AND WILL CONTINUE  
INTO NEXT WEEK AS THE NEXT WEATHER SYSTEM MOVES INTO THE REGION.  
ALTHOUGH THIS SYSTEM WILL BE DRY, TEMPERATURE WILL COOL AS IT  
REACHES THE REGION.  
 

 
   
DISCUSSION
 
 
UPPER LEVEL WV IMAGERY SHOWS RIDGING ALONG WITH DRY AIR ALOFT  
OVER THE REGION. PEAK H5 HEIGHTS TODAY AND TOMORROW WILL GENERALLY  
BE BETWEEN 584-586, CAUSING HIGH TEMPERATURES TO WARM TO 100-108  
DEGREES ACROSS THE LOWER DESERT, AND UPPER 80S TO UPPER 90S IN  
THE HIGHER TERRAINS. THESE TEMPERATURES HAVE RESULTED IN  
WIDESPREAD MODERATE HEATRISK AND SOME MORE LOCALIZED MAJOR  
HEATRISK FOR BOTH TODAY AND TOMORROW. SMART HEAT SAFETY OVER THE  
WEEKEND WILL BE IMPORTANT SO LIMIT OUTDOOR TIME, WEAR SUNSCREEN,  
WEAR LIGHT/LOOSE FITTING CLOTHING AND STAY HYDRATED. WHILE HIGH  
TEMPERATURES TOMORROW ARE EXPECTED TO BE SIMILAR TO TODAY'S, AN  
INCREASE IN CLOUD COVERAGE COULD KEEP SOME LOCATIONS FROM REACHING  
THE CURRENT NBM FORECAST.  
 
TODAY BREEZY CONDITIONS HAVE DEVELOPED OUT OF THE EAST/SOUTHEAST  
AS THE PRESSURE GRADIENT TIGHTENED BETWEEN THE LOW PRESSURE OVER LOUISIANA  
AND THE HIGH PRESSURE CENTERED OVERHEAD TODAY. WIND GUSTS TODAY  
WILL BE DIMINISHING THROUGHOUT THE AFTERNOON/EVENING AS THE PEAK  
GUSTS, 25-35 MPH, WERE MOSTLY THIS MORNING. TOMORROW A SIMILAR  
WIND PATTERN WILL TAKE HOLD BUT SPEEDS WILL BE ROUGHLY 5 MPH  
LOWER.  
 
GLOBAL ENSEMBLES SHOW THE AFOREMENTIONED LOW PRESSURE, CURRENTLY IN  
THE GULF OF ALASKA, MOVING ONSHORE IN THE PACIFIC NORTHWEST BY LATE  
THIS WEEKEND/VERY EARLY NEXT WEEK. DURING THE EARLY APPROACH OF  
THIS SYSTEM (MONDAY) TEMPERATURES IN THE LOWER DESERTS WILL EVER  
SO SLIGHTLY COOL WITH FORECASTED AFTERNOON HIGHS IN THE HIGH 90S,  
TO LOW 100S. AS THIS SYSTEM MOVES MORES FURTHER INTO WESTERN CONUS  
(TUESDAY/WEDNESDAY), WE WILL SEE ADDITIONAL COOLING, WITH  
WEDNESDAY FORECASTING HIGH TEMPERATURES IN THE MID TO HIGH 80S,  
WHICH WILL BE BELOW NORMAL. HOWEVER ENSEMBLES AGREE THAT THE  
CENTER OF THE LOW WILL STAY WELL TO OUR NORTH, RESULTING IN  
OVERALL LACKLUSTER COOLING FOR THE REGION. GLOBAL ENSEMBLE MODELS  
START TO DIFFER A LITTLE ON THE HOW LONG THE LOW WILL LINGER OVER  
WESTERN CONUS. HOWEVER, MOST MEMBERS SHOW THE LOW WEAKENING, BUT  
LINGERING ACROSS OUR REGION FOR THE LATTER HALF OF NEXT WEEK. THIS  
WOULD ALLOW TEMPERATURES TO WARM TO NEAR NORMAL FOR THE END OF  
NEXT WEEK.  
 

 
   
AVIATION
 
UPDATED AT 1710Z.  
 
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:  
NO MAJOR WEATHER ISSUES WILL EXIST THROUGH SUNDAY AFTERNOON UNDER  
CLEAR SKIES. CONFIDENCE IS VERY GOOD THAT EAST WINDS WILL PREVAIL  
THROUGH THIS AFTERNOON AND EVENING WITHOUT THE TYPICAL WESTERLY  
SWITCH. GUSTS NEAR 25KT EARLY IN THE AFTERNOON WILL ABATE BY LATE  
AFTERNOON. A FEW EASTERLY GUSTS WILL BE POSSIBLE AGAIN MID/LATE  
SUNDAY MORNING, HOWEVER LIKELY NOT NEARLY AS PRONOUNCED AS TODAY.  
 
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:  
NO SIGNIFICANT WEATHER ISSUES WILL EXIST THROUGH SUNDAY MORNING  
UNDER PERIODS OF PASSING HIGH CIRRUS DECKS. WHILE AN E/SE COMPONENT  
WILL PREVAIL THE MAJORITY OF THE PERIOD WITH A FEW STRONGER GUSTS, A  
BRIEF N/NW DRAINAGE COMPONENT SHOULD DEVELOP DURING THE LATE  
NIGHT/EARLY MORNING.  
 

 
   
FIRE WEATHER
 
 
WITH HIGH PRESSURE FIRMLY OVERHEAD THIS WEEKEND, TEMPERATURES WILL  
CLIMB INTO THE 100-108 DEGREE RANGE ACROSS THE LOWER DESERTS AND  
MOST HIGHER ELEVATIONS WILL SEE HIGH TEMPERATURES RANGING FROM THE  
UPPER 80S TO UPPER 90S. MINRHS WILL BE IN THE 7-15% RANGE THROUGH  
MONDAY. BREEZY CONDITIONS HAVE DEVELOPED THIS MORNING ACROSS  
SOUTHERN AND CENTRAL ARIZONA WITH GUSTS OF 25-35 MPH OUT OF THE  
EAST/SOUTHEAST. SPEEDS WILL DECREASE A LITTLE THROUGHOUT THE  
AFTERNOON/EVENING. A SIMILAR WIND PATTERN IS EXPECTED TOMORROW  
WITH SPEEDS AROUND 5 MPH LOWER THAN TODAY. THE BREEZY CONDITIONS  
WILL ALSO EXPAND INTO THE WESTERN DISTRICTS TOMORROW. THESE BREEZY  
CONDITIONS AND LOW RHS COULD RESULT IN SOME ELEVATED FIRE DANGER  
IN SOME AREAS THIS WEEKEND. A LOW PRESSURE SYSTEM WILL MOVE INTO  
THE REGION EARLY NEXT WEEK. WHILE THIS SYSTEM WILL BRING COOLER  
CONDITIONS IT WILL ALSO BRING MORE BREEZY TO WINDY CONDITIONS  
LIKELY LEADING TO A CONTINUATION OF ELEVATED FIRE DANGER.  
 

 
   
PSR WATCHES/WARNINGS/ADVISORIES
 
 
AZ...NONE.  
CA...NONE.  

 
 

 
 
DISCUSSION...BERISLAVICH/RYAN  
AVIATION...18  
FIRE WEATHER...BERISLAVICH/RYAN  
 
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