795  
FXUS65 KPSR 132022  
AFDPSR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PHOENIX AZ  
120 PM MST TUE MAY 13 2025  
   
SYNOPSIS  
 
A WEATHER DISTURBANCE PUSHING THROUGH THE REGION WILL RESULT IN  
GUSTY WINDS SLOWLY WEAKENING AND TEMPERATURES FALLING INTO A BELOW  
NORMAL RANGE THE NEXT COUPLE DAYS. HOWEVER, WEAK HIGH PRESSURE WILL  
BUILD BACK INTO THE AREA ALLOWING TEMPERATURES TO MODERATE BACK TO  
NEAR NORMAL LATER THIS WEEK. ANOTHER DRY WEATHER SYSTEM WILL SWEEP  
INTO THE SOUTHWEST EARLY NEXT WEEK YIELDING ANOTHER ROUND OF GUSTY  
WINDS AND COOLER THAN NORMAL TEMPERATURES.  
 
 
   
DISCUSSION  
 
EARLY AFTERNOON WV IMAGERY AND OBJECTIVE ANALYSIS DEPICTS NEGATIVE  
HEIGHT ANOMALIES MIGRATING INTO THE GREAT BASIN WITH THE TROUGH BASE  
AND ENHANCED JET CORE PROPAGATING THROUGH THE FORECAST AREA. WHILE  
THE MOST ROBUST HEIGHT FALLS WILL REMAIN WELL NORTH OF THE CWA, DEEP  
MIXING DEPTHS AND SUFFICIENT PRESSURE GRADIENT HAS RESULTED IN VERY  
GUSTY WINDS IMPACTING MUCH OF THE REGION. NOT SURPRISINGLY, THE MOST  
PRONOUNCED GUSTS HAVE BEEN MEASURED NEAR TERRAIN FEATURES, AND  
VARIOUS HEADLINE PRODUCTS REMAIN IN EFFECT THROUGH THIS EVENING. AS  
THE CIRCULATION CENTER EJECTS INTO THE CENTRAL/NORTHERN PLAINS  
WEDNESDAY, GRADIENT WILL RELAX FORCING WINDS BACK INTO A MORE  
TRADITIONAL LATE SPRING PATTERN. HOWEVER, H5 HEIGHTS WILL REMAIN  
DEPRESSED IN A 570-574DM RANGE YIELDING HIGH TEMPERATURES SOME 4F-8F  
BELOW THE DAILY NORMALS.  
 
FOLLOWING THE PASSAGE OF THE AFOREMENTIONED TROUGH, BROAD  
CYCLONIC/QUASI ZONAL FLOW WILL PREVAIL OVER THE SW CONUS THROUGH THE  
REMAINDER OF THIS WEEK WITH H5 HEIGHTS ONLY GRADUALLY REBOUNDING  
AROUND 576DM. AS THE LOWER/MIDDLE TROPOSPHERIC THERMAL PROFILES  
MODERATE, MODEL GUIDANCE SPREAD REMAINS EXTREMELY NARROW  
HIGHLIGHTING EXCELLENT FORECAST CONFIDENCE OF TEMPERATURES RETURNING  
TO NEAR NORMAL LEVELS. FORECAST UNCERTAINTY INCREASES EARLY NEXT  
WEEK AS OPERATIONAL AND ENSEMBLE GUIDANCE SHOW ANOTHER TROUGH WITH  
DEEP NEGATIVE HEIGHT ANOMALIES PROPAGATING INTO THE GREAT BASIN.  
ENSEMBLE MEMBERSHIP IS MOST DISPERSIVE WITH RESPECT TO THE DEPTH OF  
THIS TROUGH AND EQUATORWARD EXTENT OF THE COLD CORE AND ASSOCIATED  
VORTICITY CENTERS. OVERALL ENSEMBLE FORECAST TRENDS OF A DEEPER AND  
SLOWER TROUGH EVOLUTION MATCHES A CONCEPTUAL PREFERRED FLOW PATTERN  
UNDER THE CIRCUMSTANCES, AND WOULD STILL FAVOR THE SLOWER, DEEPER  
MODEL FORECASTS. REGARDLESS, THERE IS SUFFICIENT MODEL AGREEMENT  
SUGGESTING ANOTHER ROUND OF GUSTY WINDS AND COOLER TEMPERATURES  
IMPACTING THE REGION DURING THE FIRST HALF OF NEXT WEEK.  
 
 
   
AVIATION  
UPDATED AT 1720Z.  
 
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:  
GUSTY WSW WINDS WILL BE THE PRIMARY AVIATION CONCERN DURING THE  
TAF PERIOD UNDER FEW HIGH CLOUDS. GUSTS TO AROUND 25 KTS WILL PICK  
UP OVER THE NEXT FEW HOURS AND PERSIST INTO EARLY THIS EVENING,  
EVENTUALLY SUBSIDING BY 03-04Z. THOUGH W-SW WINDS ARE ANTICIPATED TO  
PREVAIL THROUGH THE OVERNIGHT HOURS, DIRECTIONS MAY TRY TO SHIFT S-  
SE OR BECOME VRB FOR A PERIOD EARLY WEDNESDAY MORNING. CONFIDENCE IS  
TOO LOW TO INCLUDE S-SE WINDS EARLY WEDNESDAY MORNING AT ANY OF THE  
TERMINALS EXCEPT FOR KIWA, SO HAVE OPTED FOR PREVAILING VRB GROUPS  
AT THE OTHER SITES, WITH SPEEDS AOB 6 KTS DURING THAT TIMEFRAME.  
 
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:  
GUSTY WINDS AND THE POTENTIAL FOR BRIEF VISIBILITY RESTRICTIONS FROM  
BLOWING DUST WILL CONTINUE TO BE THE PRIMARY AVIATION CONCERNS AT  
THE SE CALIFORNIA TERMINALS UNDER FEW OCCASIONAL HIGH CLOUDS. WINDS  
WILL REMAIN WESTERLY AT KIPL AND SOUTHWESTERLY AT KBLH THROUGH MUCH  
OF THE TAF PERIOD AND ARE EXPECTED TO SHIFT NW WEDNESDAY MORNING  
AFTER SUNRISE. AT KIPL, GUSTS OF 25-30 KT WILL CONTINUE THROUGH THE  
AFTERNOON AND WILL THEN PICK UP LATE THIS AFTERNOON WITH GUSTS OF 30-  
35 KT EXPECTED THROUGH THE EVENING. GUSTS WILL FINALLY START TO  
SUBSIDE DURING THE OVERNIGHT/EARLY MORNING HOURS WEDNESDAY. AT KBLH,  
WINDS WILL PICK UP OVER THE NEXT FEW HOURS, WITH GUSTS TO AROUND 25  
KTS BECOMING COMMON DURING THE AFTERNOON AND EARLY EVENING.  
 
 
   
FIRE WEATHER  
 
WEAKENING WIND SPEEDS AND COOLING TEMPERATURES WILL REDUCE THE FIRE  
DANGER THE NEXT SEVERAL DAYS, HOWEVER ANOTHER INCOMING SYSTEM WILL  
ALLOW WINDS TO STRENGTHEN AGAIN OVER THE WEEKEND. UNDER MORE TYPICAL  
SPRINGTIME UPSLOPE GUSTINESS, MINIMUM HUMIDITY VALUES WILL FALL INTO  
THE TEENS THE NEXT SEVERAL DAYS FOLLOWING POOR TO FAIR OVERNIGHT  
RECOVERY OF 20-50%. GUSTY WINDS WILL MATERIALIZE AGAIN THIS WEEKEND  
WITH THE NEXT WEATHER DISTURBANCE, HOWEVER COOLING TEMPERATURES AND  
INCREASED HUMIDITY LEVELS MAY PRECLUDE WIDESPREAD CRITICAL  
CONDITIONS. AT THIS TIME, SATURDAY AFTERNOON POSES THE GREATEST  
THREAT OF AN ELEVATED FIRE DANGER.  
 
 
   
PSR WATCHES/WARNINGS/ADVISORIES  
 
AZ...RED FLAG WARNING UNTIL 8 PM MST THIS EVENING FOR AZZ133.  
 
CA...WIND ADVISORY UNTIL 5 AM PDT WEDNESDAY FOR CAZ562.  
 
WIND ADVISORY UNTIL 2 AM PDT WEDNESDAY FOR CAZ563-566-567.  
 
 
 
 
 
DISCUSSION...18/SMITH  
AVIATION...WHITTOCK  
FIRE WEATHER...18  
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