193  
FXUS65 KPSR 101009  
AFDPSR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PHOENIX AZ  
309 AM MST SAT MAY 10 2025  
   
SYNOPSIS
 
 
THE TEMPERATURES THIS WEEKEND ARE FORECASTED TO BE THE HOTTEST  
TEMPERATURES OF THE YEAR, SO FAR. WITH HIGH PRESSURE FIRMLY OVERHEAD  
IT WILL ALLOW TEMPERATURES TO WARM INTO THE 100-108 DEGREE RANGE  
ACROSS THE LOWER DESERTS. THESE SEASONABLY HOT TEMPERATURES WILL  
RESULT IN WIDESPREAD MODERATE TO LOCALIZED MAJOR HEATRISK ACROSS THE  
LOWER DESERTS. DAILY BREEZY CONDITIONS WILL DEVELOP LATER THIS  
MORNING AND CONTINUE INTO NEXT WEEK AS THE NEXT WEATHER SYSTEM MOVES  
INTO THE REGION BY THE BEGINNING OF NEXT WEEK. THIS WEATHER SYSTEM  
WILL BE DRY, BUT IT WILL BRING COOLER TEMPERATURE BACK TO THE  
REGION.  
 

 
   
DISCUSSION
 
 
EARLY THIS MORNING UPPER-LEVEL WATER VAPOR IMAGERY DEPICTS HIGH  
PRESSURE OVER SOUTHWESTERN CONUS, A LOW OVER LOUISIANA, A LOW OVER  
NEW ENGLAND, AND A LOW IN THE GULF OF ALASKA. H5 HEIGHTS OVERHEAD  
ARE CURRENTLY AROUND 582DM AND ARE EXPECTED TO STRENGTHEN TO 583-  
585DM THIS AFTERNOON AS THE CENTER OF THE HIGH PRESSURE SYSTEM MOVES  
OVERHEAD. THE HIGH PRESSURE SYSTEM WON'T MOVE MUCH TOMORROW AS H5  
HEIGHTS ARE EXPECTED TO BE SIMILAR TO TODAY. AS A RESULT FORECASTED  
HIGH TEMPERATURES FOR THIS AFTERNOON AND TOMORROW AFTERNOON ARE VERY  
SIMILAR. LOWER DESERT COMMUNITIES ARE FORECASTED TO SEE HIGHS IN  
THE 100-108 DEGREE RANGE WITH HIGHER ELEVATION AREAS FORECASTED TO  
SEE HIGHS RANGING FROM THE UPPER 80S TO THE UPPER 90S. THESE HOT  
TEMPERATURES WILL RESULT IN LOCALIZED AREAS OF MAJOR HEATRISK,  
WITH WIDESPREAD MODERATE HEATRISK ACROSS THE LOWER DESERTS FOR  
TODAY AND TOMORROW. THE HIGH TEMPERATURES THIS WEEKEND ARE  
FORECASTED TO BE THE HOTTEST OF THE YEAR, SO FAR. SO MAKE SURE TO  
PRACTICE SMART HEAT SAFETY BY LIMITING YOUR TIME OUTDOORS, WEARING  
SUNSCREEN, WEARING LIGHT LOOSE FITTING CLOTHES, AND STAYING  
HYDRATED. ONE CAVEAT TO THE CURRENT FORECAST IS THAT TOMORROW  
AFTERNOON WE WILL SEE INCREASING HIGHER LEVEL CLOUDS MOVE INTO THE  
REGION WHICH COULD KEEP SOME LOCATIONS FROM REACHING THE CURRENT  
NBM FORECAST HIGHS.  
 
AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW PRESSURE OVER  
LOUISIANA AND THE HIGH PRESSURE AS THE CENTER MOVES OVERHEAD TODAY  
BREEZY CONDITIONS WILL DEVELOP OUT OF THE EAST/SOUTHEAST. THESE  
BREEZY CONDITIONS ARE EXPECTED TO DEVELOP ACROSS MUCH OF SOUTHERN  
AND CENTRAL ARIZONA BEGINNING AROUND SUNRISE THIS MORNING. WIND  
GUSTS OF 25-35 MPH ARE EXPECTED THIS MORNING WITH A SLIGHT DECREASE  
HEADING INTO THE AFTERNOON HOURS. WINDS WILL SET UP VERY SIMILAR  
TOMORROW, BUT SPEEDS WILL BE AROUND 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. ENSEMBLES SHOW THE LOW  
APPROACHING OUR AREA AROUND TUESDAY. AS THIS LOW PRESSURE MOVES  
ONSHORE AND PUSHES INTO OUR REGION TEMPERATURES WILL START TO  
DECREASE. AFTERNOON HIGH TEMPERATURES ON MONDAY ARE FORECASTED TO  
BE IN THE UPPER 90S TO LOW 100S ACROSS THE LOWER DESERTS. FURTHER  
COOLING WILL TAKE PLACE AS THE LOW PUSHES INTO OUR REGION ON  
TUESDAY AND ON WEDNESDAY AS THE BASE OF THE TROUGH MOVES THROUGH  
OUR AREA. ENSEMBLES AGREE THAT THE CENTER OF THE LOW WILL STAY  
WELL TO OUR NORTH, SO WE WON'T SEE AS DRAMATIC OF A COOL DOWN AS  
WE DID AT THE BEGINNING OF THIS WEEK. BUT, TEMPERATURES ARE  
CURRENTLY FORECASTED TO FALL BELOW NORMAL ON WEDNESDAY, WITH  
AFTERNOON HIGH TEMPERATURES CURRENTLY FORECASTED TO BE IN THE 80S  
ACROSS THE LOWER DESERTS. 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 0020Z.  
 
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:  
EASTERLY WINDS WILL PREVAIL THROUGH THE TAF PERIOD. AN ENHANCED  
EASTERLY GRADIENT WIND WILL DEVELOP TONIGHT, SHORTLY AFTER  
MIDNIGHT. WINDS ABOVE THE SURFACE AS HIGH AS 30-35 KTS MAY LEAD  
LLWS MAGNITUDES UP TO 25-30 KTS BETWEEN 7-14Z, BUT MENTION WILL BE  
LEFT OUT OF THE TAF. THE ELEVATED WINDS WILL LEAD TO SURFACE WIND  
GUSTS TO AROUND 25-30 KTS SATURDAY, MAINLY BETWEEN 15-20Z. GUST  
MAGNITUDES WILL SUBSIDE GRADUALLY THROUGH SATURDAY AFTERNOON.  
SKIES WILL REMAIN MOSTLY CLEAR.  
 
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:  
LIGHT DIURNAL WINDS WILL PREVAIL AT BOTH TERMINALS THROUGH  
TONIGHT, WITH PERIODS OF LIGHT VARIABILITY AS WELL. AN INCREASED  
EASTERLY WIND GRADIENT WILL THEN TAKE HOLD BY LATE MORNING AT BOTH  
TERMINALS, WITH SURFACE SPEEDS INCREASING TO AROUND 8-13 KTS WITH  
GUSTS UP TO 15-25 KTS THAT WILL CONTINUE THROUGH EARLY AFTERNOON  
SATURDAY. MOSTLY CLEAR SKIES WILL PREVAIL, WITH FEW TO SCT HIGH  
CLOUDS MOVING IN LATE IN THE AFTERNOON AND EVENING SATURDAY.  
 

 
   
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 WILL DEVELOP AROUND SUNRISE  
ACROSS SOUTHERN AND CENTRAL ARIZONA WITH GUSTS OF 25-35 MPH  
EXPECTED OUT OF THE EAST/SOUTHEAST. SPEEDS WILL DECREASE A LITTLE  
HEADING INTO THE AFTERNOON TODAY. 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  
AVIATION...BENEDICT  
FIRE WEATHER...BERISLAVICH  
 
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