585  
FXUS65 KPSR 111157  
AFDPSR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PHOENIX AZ  
457 AM MST THU AUG 11 2022  
   
UPDATE
 
UPDATED AVIATION DISCUSSION.  
 

 
   
SYNOPSIS
 
 
TODAY SHOULD BRING A BRIEF BREAK FROM FAIRLY WIDESPREAD MONSOON  
STORMS WITH HIGH TEMPERATURES REMAINING NEAR NORMAL. CHANCES FOR  
SHOWERS AND THUNDERSTORMS ARE THEN LIKELY TO PICK BACK UP STARTING  
FRIDAY AND LAST THROUGH AT LEAST THE WEEKEND WITH HEAVY RAINFALL,  
LOCALIZED FLASH FLOODING, GUSTY WINDS, AND LOCALIZED BLOWING DUST  
POSSIBLE. TEMPERATURES ARE THEN EXPECTED TO DROP TO SLIGHTLY  
BELOW NORMAL READINGS OVER THE WEEKEND INTO EARLY NEXT WEEK.  
 

 
   
DISCUSSION
 
 
YESTERDAY WAS A FAIRLY ACTIVE MONSOON STORM DAY, PARTICULARLY  
ACROSS WESTERN AND CENTRAL ARIZONA. THE LARGE SCALE WEATHER  
PATTERN WILL CHANGE VERY LITTLE THROUGH AT LEAST THE WEEKEND WITH  
A STRONG SUB-TROPICAL HIGH CENTERED OVER COLORADO PROVIDING  
PERSISTENT SOUTHEASTERLY MOIST FLOW INTO OUR REGION. GIVEN THE  
ACTIVE DAY YESTERDAY, THE ATMOSPHERE WILL OVERALL BE LESS  
CONDUCIVE FOR STORM ACTIVITY TODAY. CURRENT IR SATELLITE IMAGERY  
SHOWS LINGERING DEBRIS CLOUD FROM EARLIER STORM ACTIVITY ACROSS  
SOUTHERN ARIZONA AND A WEAKENING STORM COMPLEX OVER NORTHERN  
MEXICO. A REMNANT MCV IS ALSO CURRENTLY DRIFTING SLOWLY  
NORTHWESTWARD ACROSS THE PHOENIX AREA WITH HI-RES GUIDANCE SHOWING  
THIS FEATURE LIKELY PROVIDING A FOCUS MECHANISM FOR STORMS  
NORTHWEST OF OUR AREA LATER TODAY, BUT KEEPING FAIRLY SUBSIDENT  
FLOW OVER SOUTH-CENTRAL ARIZONA. 00Z HREF AND LATEST HRRR AGREES  
TODAY SHOULD BE AN OVERALL DOWN MONSOON DAY WITH A FEW ISOLATED  
STORMS POSSIBLE OVER THE WESTERN DESERTS AND OVER THE EASTERN  
ARIZONA HIGH TERRAIN, BUT LIKELY NOT MUCH OF ANYTHING IN THE  
PHOENIX AREA. LOCALIZED MODERATE HEATRISK TODAY SHOULD BE THE  
BIGGEST IMPACT WITH TEMPERATURES NEAR NORMALS, BUT ELEVATED  
HUMIDITIES MAKING IT FEEL QUITE UNCOMFORTABLE. OVERNIGHT  
TEMPERATURES WILL ALSO NOT RECOVER ALL THAT WELL THROUGH FRIDAY  
MORNING WITH LOWS MOSTLY IN A 83-88 DEGREE RANGE OVER THE LOWER  
DESERTS.  
 
STARTING FRIDAY, GUIDANCE IS SUGGESTING A RETURN TO MORE FAVORABLE  
MONSOON STORM CONDITIONS WITH INCREASED INSTABILITY. THERE ARE  
ALSO SIGNS OF ANOTHER POTENTIAL INVERTED TROUGH TRACKING INTO  
SOUTHERN ARIZONA PROVIDING AREAS OF ASCENT ON FRIDAY, WHILE OUR  
AREA MAY ALSO SEE MORE BROAD SCALE UPPER LEVEL ASCENT AS MODELS  
SHOW AT LEAST WESTERN ARIZONA FALLING WITHIN THE RIGHT ENTRANCE  
REGION OF A JET STREAK POSITIONED TO OUR NORTHWEST. NBM POPS  
INCREASE TO ROUGHLY 30-40% OVER THE MAJORITY OF THE LOWER DESERTS  
STARTING FRIDAY TO 50-70% OVER HIGHER TERRAIN AREAS OF EASTERN  
ARIZONA, LASTING THROUGH THE WEEKEND AREAWIDE. MOISTURE LEVELS  
THROUGH THE PERIOD WILL REMAIN PLENTY SUFFICIENT FOR HEAVY  
RAINFALL POTENTIAL, BUT LIKELY NOT TOO EXCESSIVE TO WHERE WE LOSE  
SUFFICIENT INSTABILITY FOR STRONG THUNDERSTORMS. POTENTIAL IMPACTS  
STARTING FRIDAY WILL INCLUDE STRONG WINDS, BLOWING DUST, HEAVY  
RAINFALL, AND LOCALIZED FLOODING. ANY OF THOSE DAYS COULD BE QUITE  
ACTIVE, BUT IF ONE DAY SEES WIDESPREAD STORMS, THE SUBSEQUENT DAY  
IS LIKELY TO BE FAIRLY QUIET AS THE ATMOSPHERE WILL NEED TIME TO  
DESTABILIZE. RELATIVELY WEAK WIND SHEAR IS EXPECTED THROUGH THE  
PERIOD, SO INDIVIDUAL STORMS ARE NOT LIKELY TO MAINTAIN THEMSELVES  
FOR LONG, BUT CLUSTERS OF STORMS FORMING OVER HIGHER TERRAIN  
AREAS MAY LEAD TO ADDITIONAL STORM DEVELOPMENT INTO THE LOWER  
DESERTS ALONG A DEEP OUTFLOW OR COLLIDING OUTFLOWS. SHOWERS AND  
STORM DEVELOPMENT WILL ALSO BE POSSIBLE WITH ANY REMNANT MCVS OR  
INVERTED TROUGHS THAT TRAVERSE THE AREA.  
 
AT SOME POINT EARLY NEXT WEEK, THE PATTERN WILL BEGIN TO SHIFT  
WITH THE SUB-TROPICAL HIGH TO OUR NORTHEAST WEAKENING, WHILE A  
WEAK TROUGH POSSIBLY SETS UP OFF THE SOUTHERN CALIFORNIA COAST.  
THIS SCENARIO MAY NOT BRING MUCH OF A CHANGE TO OUR AREA WITH  
MODELS CONTINUING TO SHOW ADEQUATE MOISTURE LEVELS FOR STORMS, BUT  
OVERALL FORECAST CONFIDENCE IS LOW DUE TO THE CHANGE IN THE UPPER  
LEVEL PATTERN AND SOME MODEL DIFFERENCES. TEMPERATURES ARE  
EXPECTED TO COOL OFF SLIGHTLY AT SOME POINT OVER THE WEEKEND INTO  
EARLY NEXT WEEK WITH FORECAST HIGHS CLOSER TO 100 DEGREES DUE TO  
ANTICIPATED MORE ACTIVE MONSOON CONDITIONS.  
 

 
   
AVIATION
 
UPDATED 1156Z.  
 
SOUTH-CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:  
LIGHT WINDS FAVORING THE E TO SE WILL CONTINUE THROUGH THE MORNING  
BEFORE SWITCHING AROUND TO THE WEST BY EARLY THIS AFTERNOON.  
ANOTHER DAY OF STORMS BOTH N AND SE OF THE METRO WILL LIKELY CAUSE  
OUTFLOW BOUNDARIES TO MAKE A RUN FOR THE AREA IN THE EARLY  
EVENING. AT THIS TIME, THE SE OUTFLOW LOOKS MORE DOMINANT - SO IT  
IS REFLECTED IN THE TAF AS SUCH; PROBABILITY OF WIND GUSTS  
EXCEEDING 30KT IS ONLY AROUND 30% IN THE EARLY EVENING. ANY STRONG  
OUTFLOWS WILL POSE THE POTENTIAL FOR BLOWING DUST, WHICH WILL IN  
RETURN LOWER VISIBILITY. THERE WILL BE A 30% CHANCE FOR ISOLATED  
SHOWER/THUNDERSTORM DEVELOPMENT AS OUTFLOWS APPROACH THE VALLEY.  
 
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:  
WINDS WILL GENERALLY FAVOR A SOUTHERLY COMPONENT THROUGH THE  
PERIOD WITH DIRECTIONS BECOMING VARIABLE AT TIMES. CHANCES FOR  
SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING ARE AROUND  
20% OR LESS AT THE TERMINALS. ANY THUNDERSTORM THAT MAY DEVELOP  
WOULD BE CAPABLE OF GUSTY ERRATIC WINDS, BLOWING DUST, AND LOCALLY  
HEAVY RAINFALL.  
 

 
   
FIRE WEATHER
 
 
AMPLE MONSOONAL MOISTURE IS EXPECTED TO PERSIST THROUGH AT LEAST  
THE FIRST HALF OF NEXT WEEK KEEPING THE FIRE DANGER THREAT LOW.  
THIS MOIST AIRMASS WILL CONTINUE TO YIELD ELEVATED HUMIDITIES  
WITH AFTERNOON MINIMUM RH VALUES MOSTLY IN A 30-35% RANGE,  
LOCALLY HIGHER, AND GOOD OVERNIGHT RECOVERY. CHANCES FOR WETTING  
RAINS WILL CONTINUE FOR MOST AREAS ALMOST DAILY. WINDS FOR THE  
MOST PART WILL REMAIN LIGHT, WITH THE EXCEPTION OF THUNDERSTORM  
OUTFLOWS GENERATING STRONGER GUSTS.  
 

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

 
 

 
 
DISCUSSION...KUHLMAN  
AVIATION...SMITH/HEIL  
FIRE WEATHER...KUHLMAN  
 
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