077  
FXUS65 KPSR 151122  
AFDPSR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PHOENIX AZ  
422 AM MST THU MAY 15 2025  
   
UPDATE
 
UPDATED 12Z AVIATION DISCUSSION  
 

 
   
KEY MESSAGES
 
 
1) NEAR TO BELOW NORMAL TEMPERATURES THROUGH THE BEGINNING OF  
NEXT WEEK  
 
2) GUSTY WINDS OVER THE WEEKEND RESULTING IN A LOCALLY ELEVATED  
FIRE DANGER  
 
3) MEDIUM TO HIGH POTENTIAL FOR HOT TEMPERATURES AND WIDESPREAD  
MODERATE HEATRISK RETURNING LATE NEXT WEEK  
 

 
   
DISCUSSION
 
 
WEATHER PATTERN OVERVIEW:  
THE SHORTWAVE TROUGH THAT EXITED THE REGION YESTERDAY IS NOW  
MOVING INTO THE NORTHERN PLAINS, BUT LARGE SCALE TROUGHING REMAINS  
IN PLACE OVER THE BULK OF THE WESTERN U.S., INCLUDING OUR REGION.  
THIS PATTERN WILL REMAIN IN PLACE FOR TODAY AND FRIDAY, BUT WE  
WILL SEE SOME MODEST HEIGHT RISES ALOFT AND SOME WARMING BRINGING  
OUR DAYTIME HIGHS UP TO AROUND 90 DEGREES TODAY AND INTO THE LOWER  
90S TO UP TO 95 DEGREES ON FRIDAY.  
 
THIS TRANQUIL WEATHER WILL BEGIN TO CHANGE BY SATURDAY AS A FAST  
MOVING SHORTWAVE TROUGH DIVES SOUTH SOUTHEASTWARD THROUGH  
CALIFORNIA BRINGING INCREASING HEIGHT FALLS ACROSS MUCH OF THE  
DESERT SOUTHWEST. AS A RESULT, WINDS WILL BECOME BREEZY TO LOCALLY  
WINDY BY EARLY AFTERNOON SATURDAY, ESPECIALLY ACROSS THE WESTERN  
DESERTS WHERE ADVISORY LEVEL WINDS MAY BECOME POSSIBLE. WINDS  
ACROSS SOUTHERN AND CENTRAL ARIZONA WILL ALSO BECOME BREEZY BY MID  
TO LATE AFTERNOON WITH GUSTS MAINLY BETWEEN 20-30 MPH. THESE  
GUSTY WINDS AND LOW RHS DOWN TO 10% SATURDAY AFTERNOON/EARLY  
EVENING ARE LIKELY TO RESULT IN ELEVATED FIRE WEATHER CONDITIONS.  
 
ENSEMBLE GUIDANCE SHOWS VERY GOOD AGREEMENT SHOWING THE TRACK OF  
THIS INITIAL SHORTWAVE ACROSS NORTHERN ARIZONA SATURDAY NIGHT INTO  
SUNDAY BEFORE A SECONDARY SHORTWAVE IS LIKELY TO FOLLOW A FAIRLY  
SIMILAR TRACK ACROSS THE GREAT BASIN INTO NORTHERN ARIZONA LATE  
SUNDAY INTO MONDAY. BOTH OF THESE DISTURBANCES WILL BE QUITE  
MOISTURE STARVED, BUT GUIDANCE SHOWS THE SECOND ONE ADVECTING IN A  
BIT MORE MOISTURE OFF THE PACIFIC PUSHING LOW LEVEL MIXING RATIOS  
CLOSER TO 5 G/KG AND SURFACE DEW POINTS INTO THE 40S. NBM POPS DO  
SHOW SOME 10-20% CHANCES FOR SHOWERS AS FAR SOUTH AS THE HIGHER  
TERRAIN EAST OF PHOENIX DURING THE DAYTIME MONDAY WITH THE BEST  
CHANCES OVER NORTHEAST ARIZONA.  
 
WINDS ON SUNDAY ARE ALSO EXPECTED TO BE BREEZY TO LOCALLY WINDY,  
ESPECIALLY ACROSS SOUTHEAST CALIFORNIA AND THE ARIZONA HIGHER  
TERRAIN, WHILE TEMPERATURES TAKE A DIP WITH HIGHS FALLING BACK TO  
BETWEEN 80-85 DEGREES. AS THE SECOND SHORTWAVE MOVES THROUGH  
NORTHERN PORTIONS OF OUR REGION ON MONDAY, WINDS WILL AGAIN BE  
BREEZY BUT LIKELY TO A LESSER DEGREE COMPARED TO THE WEEKEND.  
TEMPERATURES WILL ALSO BEGIN TO WARM UP ACROSS THE WESTERN DESERTS  
BEGINNING MONDAY WITH HIGHS APPROACHING THE 90 DEGREE MARK.  
 
UPPER LEVEL RIDGING IS EXPECTED TO QUICKLY SPREAD OVER THE REGION  
BY NEXT TUESDAY INTO WEDNESDAY WITH ENSEMBLES HEAVILY FAVORING  
FURTHER STRENGTHENING LATE NEXT WEEK. TEMPERATURES WILL BE QUICK  
TO RESPOND TO THE INCREASING HEIGHTS ALOFT WITH HIGHS WARMING  
TO AROUND 100 DEGREES BY WEDNESDAY AND LIKELY ECLIPSING 105  
DEGREES AT SOME POINT LATE NEXT WEEK INTO NEXT WEEKEND. THE NBM IS  
ALSO SHOWING AROUND A 10% PROBABILITY OF REACHING 110 DEGREES  
ACROSS THE TYPICAL HOTTER LOWER DESERTS NEXT FRIDAY AND SATURDAY.  
GIVEN THE GOOD ENSEMBLE AGREEMENT, WE ARE QUITE LIKELY TO SEE  
WIDESPREAD MODERATE HEATRISK FOR AT LEAST THE FIRST PART OF THE  
MEMORIAL DAY WEEKEND.  
 
FORECAST CONFIDENCE & DEVIATIONS:  
MODEL GUIDANCE IS IN VERY GOOD AGREEMENT THROUGH AT LEAST THE  
COMING WEEKEND PROVIDING LITTLE EXPECTED CHANGES IN THE FORECAST  
OVER THE NEXT FEW DAYS. THE WIND FORECAST VERY WELL COULD INCREASE  
MARGINALLY OVER THE WEEKEND, BUT NOT LIKELY BY MORE THAN 20-30%.  
MODEL SPREAD FOR NEXT WEEK IS HIGHER, ESPECIALLY TOWARD NEXT  
WEEKEND, BUT OVERALL IT IS STILL GOOD GIVING US MEDIUM TO HIGH  
FORECAST CONFIDENCE IN MODERATE HEATRISK DEVELOPING BY AROUND NEXT  
THURSDAY. OVERALL THIS FORECAST PACKAGE HAD NO APPRECIABLE  
DEVIATION FROM THE MANDATED NBM INITIALIZATION.  
 

 
   
AVIATION
 
UPDATED AT 120Z.  
 
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:  
WINDS WILL FOLLOW THEIR TYPICAL DIURNAL TENDENCIES THROUGH THE TAF  
PERIOD. LIGHT EASTERLY WINDS, WITH PERIODS OF CALM WINDS, WILL  
CONTINUE THROUGH MOST OF THE MORNING. WINDS WILL THEN BECOME  
WESTERLY BY LATE THIS MORNING/EARLY THIS AFTERNOON WITH SPEEDS  
GENERALLY AOB 8 KT. SOME OCCASIONAL GUSTS INTO THE MID-TEENS WILL  
BE POSSIBLE THIS AFTERNOON. WINDS WILL THEN GO BACK EASTERLY LATE  
TONIGHT/DURING THE OVERNIGHT HOURS, WITH SPEEDS AOB 5 KT WITH  
PERIODS OF LIGHT AND VARIABLE TO CALM WINDS. SKIES WILL BE MOSTLY  
CLEAR.  
 
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:  
CURRENT LIGHT WESTERLY WINDS WILL GO LIGHT AND VARIABLE AROUND 14Z  
AT KIPL, THEN BECOME SOUTHEASTERLY THIS AFTERNOON, THEN BACK  
WESTERLY THIS EVENING. AT KBLH, CURRENT LIGHT AND VARIABLE WINDS  
WILL DEVELOP A SOUTHERLY/SOUTHWESTERLY COMPONENT THIS AFTERNOON  
FOR THE REMAINDER OF THE TAF PERIOD. WIND SPEEDS AT BOTH TERMINALS  
WILL GENERALLY BE AOB 7 KT. SKIES WILL BE MOSTLY CLEAR.  
 

 
   
FIRE WEATHER
 
 
SEASONABLY DRY CONDITIONS, NEAR NORMAL TEMPERATURES, AND FAIRLY  
LIGHT WINDS ARE EXPECTED THROUGH FRIDAY. DAILY MINRHS WILL HOVER  
AROUND 10% WHILE OVERNIGHT RECOVERIES WILL BE FAIR TO POOR WITH  
READINGS BETWEEN 20-30% OVER THE EASTERN DISTRICTS TO 30-45% OVER  
THE WESTERN DISTRICTS. MORE UNSETTLED WEATHER IS EXPECTED FOR THE  
COMING WEEKEND WITH INCREASED WINDS AND EVENTUALLY COOLER  
TEMPERATURES STARTING SUNDAY. SATURDAY SHOULD ALSO BRING ELEVATED  
FIRE WEATHER CONDITIONS ACROSS THE EASTERN ARIZONA HIGHER TERRAIN  
WITH AFTERNOON RHS BETWEEN 10-15% AND WIND GUSTS OF 20-30 MPH.  
 

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

 
 

 
 
DISCUSSION...KUHLMAN  
AVIATION...BERISLAVICH  
FIRE WEATHER...KUHLMAN  
 
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