297  
FXUS65 KPSR 120013  
AFDPSR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PHOENIX AZ  
513 PM MST SUN MAY 11 2025  
   
UPDATE  
 
00Z AVIATION DISCUSSION.  
 
 
   
SYNOPSIS  
 
TEMPERATURES WILL COOL THROUGH THE MIDDLE OF THE WEEK AS A DRY  
WEATHER SYSTEM MOVES INTO THE REGION. ASSOCIATED WITH THIS WEATHER  
DISTURBANCE, GUSTY WINDS WILL BE COMMON THE NEXT SEVERAL DAYS.  
TEMPERATURES SHOULD SLOWLY REBOUND DURING THE LATTER HALF OF THE  
WEEK EVENTUALLY HOVERING AROUND THE SEASONAL NORMALS.  
 
 
   
DISCUSSION  
 
A BLOCKING PATTERN WHICH HAS PREDOMINATED THE CONUS WILL SLOWLY OPEN  
OVER THE NEXT SEVERAL DAYS AS A SERIES OF PROGRESSIVE PACIFIC  
DISTURBANCES AND STRONG JET ENERGY DISLODGE CUTOFF NEGATIVE HEIGHT  
ANOMALIES ACROSS THE LOWER MISSISSIPPI RIVER VALLEY. H5 HEIGHTS NEAR  
585DM OVER THE SW CONUS WHICH HAVE SUPPORTED TEMPERATURES SOME 10F  
ABOVE NORMAL WILL GRADUALLY ERODE CLOSER TO 572DM OVER THE NEXT 72  
HOURS AS MODEST HEIGHT FALLS ENTER THE REGION. WHILE THE PRIMARY  
COLD CORE/CIRCULATION CENTER AND STRONGEST FORCING WILL REMAIN NORTH  
OF THE FORECAST AREA, SUFFICIENT JET ENERGY AND HIGHER MOMENTUM  
WITHIN A SEASONALLY DEEP MIXING DEPTH WILL RESULT IN PERIODICALLY  
GUSTY WINDS EARLY IN THE WEEK. WITH MODELS DEPICTING 25-35KT WINDS  
DEVELOPING IN A H8-H7 LAYER CORRESPONDING TO THE INCOMING HEIGHT  
FALLS AND WEAKENING FRONTAL BOUNDARY, CONFIDENCE IS VERY GOOD THAT  
ENHANCED GUSTS WILL IMPACTS MUCH OF THE REGION BEGINNING IN SE  
CALIFORNIA MONDAY, THEN MIGRATING EASTWARD TUESDAY. AN ENHANCED FIRE  
DANGER AND LOCALIZED BLOWING DUST MAY BE THE MOST SIGNIFICANT  
HAZARDS WITH THIS WEATHER SYSTEM PASSAGE.  
 
ALTHOUGH THE CONUS PATTERN WILL REMAIN SLOWLY PROGRESSIVE DURING THE  
LATTER HALF OF THE WEEK, SOME MEASURE OF BROAD CYCLONIC, OR QUASI-  
ZONAL FLOW WILL SETTLE OVER THE SOUTHWEST. AS SUCH, FORECAST  
CONFIDENCE IS GOOD THAT H5 HEIGHTS SHOULD HOVER IN A 576-579DM RANGE  
WITH THE PATTERN CONFIGURATION PROHIBITING SIGNIFICANT HEIGHT RISES  
OR RAPID WARMING. INSTEAD, NARROW GUIDANCE SPREAD SUGGESTS READINGS  
RETURNING TO A NEAR NORMAL MID-MAY LEVEL PERSISTING INTO THE  
WEEKEND. ENSEMBLE SPREAD STARTS GROWING NOTABLY TOWARDS THE END OF  
THE PERIOD AS MEMBERSHIP IS SPLIT BETWEEN MAINTAINING NEGATIVE  
HEIGHT ANOMALIES OVER THE SW CONUS, OR SHIFTING MEAN TROUGHING INTO  
THE EASTERN CONUS AND ALLOWING BROAD RIDGING TO MATERIALIZE OVER THE  
FORECAST AREA. CMC MEMBERS REMAIN THE MOST AMPLIFIED WITH NEGATIVE  
ANOMALIES CENTERED OVER THE FORECAST AREA WITH TRENDS IN GEFS  
MEMBERSHIP POINTING TOWARDS HIGHER PROBABILITIES OF AMPLIFIED  
HEIGHTS AND/OR FLAT RIDGING. AT THIS TIME, THESE DISPARATE SOLUTIONS  
FORM AN ENSEMBLE MEAN NOT FAR FROM A TYPICAL, DRY QUASI-ZONAL MAY  
PATTERN.  
 
 
   
AVIATION  
UPDATED AT 0000Z.  
 
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:  
NO AVIATION CONCERNS ARE ANTICIPATED THROUGH THE FORECAST PERIOD.  
WINDS WILL REMAIN LIGHT, AOB 8 KTS OUT OF THE WSW OVER THE NEXT  
SEVERAL HOURS BEFORE BECOMING EASTERLY AT KPHX AND KIWA BY 07-09Z.  
WINDS WILL INCREASE OUT OF THE S-SE AFTER SUNRISE TOMORROW  
MORNING, RESULTING IN A SOUTHERLY CROSS-RUNWAY COMPONENT AT KPHX  
FOR APPROX 3-4 HOURS BEFORE ULTIMATELY SHIFTING OUT OF THE SW BY  
THE EARLY AFTERNOON. GUSTS BETWEEN 20-25 KTS WILL BE COMMON FROM  
THE LATE AFTERNOON THROUGH THE EARLY EVENING AT ALL TERMINALS.  
HIGH CLOUDS WILL CONTINUE TO OVERSPREAD THE REGION TONIGHT AND  
INTO TOMORROW WITH BASES REMAINING AOA 15 KFT AGL.  
 
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:  
GUSTY WINDS WILL BE THE PRIMARY AVIATION CONCERN AT THE SOUTHEAST  
CA TERMINALS, ESPECIALLY BY TOMORROW AFTERNOON AND EVENING. WINDS  
WILL CONTINUE TO REMAIN WESTERLY AT KIPL AND SOUTHERLY TO  
SOUTHWESTERLY AT KBLH THROUGH THE PERIOD. INTERMITTENT GUSTS TO  
AROUND 20 KTS WILL BE POSSIBLE AT BOTH TERMINALS THROUGH THIS  
EVENING BEFORE DIMINISHING OVERNIGHT. BY TOMORROW MORNING THROUGH  
THE AFTERNOON, STRONGER GUSTS WILL MATERIALIZE AT BOTH TERMINALS,  
REACHING 25-30 KTS AT TIMES. THERE IS A MEDIUM PROBABILITY 30-50%  
OF GUSTS EXCEEDING 35 KTS AT KIPL BY TOMORROW EVENING. HIGH CLOUDS  
WILL CONTINUE TO OVERSPREAD THE REGION THROUGH TOMORROW WITH BASES  
REMAINING AOA 20 KFT AGL.  
 
 
   
FIRE WEATHER  
 
AN ELEVATED FIRE DANGER WILL EXIST MONDAY AND TUESDAY AS WARM  
TEMPERATURES, LOW HUMIDITY LEVELS, AND GUSTY WINDS BECOME JUXTAPOSED  
WITH RECEPTIVE, DRY FINE FUELS. AFTERNOON HUMIDITY LEVELS IN THE  
TEENS WILL BE COMMON THROUGHOUT THE WEEK FOLLOWING POOR TO FAIR  
OVERNIGHT RECOVERY OF 20-50%. WIND SHOULD BE STRONGEST MONDAY AND  
TUESDAY WITH GUSTS 25-35 MPH DURING THE AFTERNOON AND EARLY EVENING.  
GUSTS WILL LIKELY BE MOST PRONOUNCED ACROSS RIDGE TOPS AND IN THE  
TYPICAL DOWNSLOPING AREAS. SPEEDS SHOULD WEAKEN DURING THE LATTER  
HALF OF THE WEEK, THOUGH STILL WILL RETAIN THE USUAL UPSLOPE  
GUSTINESS. TEMPERATURES WILL ALSO COOL DURING THE MIDDLE OF THE WEEK  
AS THE WEATHER SYSTEM MOVES INTO THE REGION, HOWEVER SHOULD REBOUND  
CLOSER TO THE SEASONAL NORMAL BY THE END OF THE WEEK.  
 
 
   
PSR WATCHES/WARNINGS/ADVISORIES  
 
AZ...NONE.  
CA...WIND ADVISORY FROM 5 AM MONDAY TO 5 AM PDT WEDNESDAY FOR CAZ562.  
 
 
 
 
 
DISCUSSION...18  
AVIATION...SALERNO  
FIRE WEATHER...18  
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