672  
ACUS11 KWNS 050051  
SWOMCD  
SPC MCD 050051  
NMZ000-AZZ000-050245-  
 
MESOSCALE DISCUSSION 1834  
NWS STORM PREDICTION CENTER NORMAN OK  
0751 PM CDT TUE AUG 04 2026  
 
AREAS AFFECTED...SOUTHEASTERN ARIZONA  
 
CONCERNING...SEVERE THUNDERSTORM WATCH 538...  
 
VALID 050051Z - 050245Z  
 
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 538  
CONTINUES.  
 
SUMMARY...THUNDERSTORM ACTIVITY APPEARS LIKELY TO CONTINUE TO  
INCREASE, PARTICULARLY TO THE EAST AND SOUTH OF TUCSON, THROUGH 7-9  
PM MST, ACCOMPANIED BY OCCASIONAL STRONG TO SEVERE OUTFLOW SURFACE  
GUSTS.  
 
DISCUSSION...DEEP-LAYER MEAN FLOW ACROSS THE SOUTHERN ARIZONA/NEW  
MEXICO STATE BORDER VICINITY AND INTERNATIONAL BORDER REMAINS LIGHT  
AND NORTHEASTERLY, BUT MID-LEVEL FLOW (AROUND 20 KT NEAR 500 MB)  
APPEARS A BIT STRONGER WITH A MORE PROMINENT EASTERLY COMPONENT THAN  
24 HOURS AGO.  
 
A SUBSTANTIVE CLUSTERING OF STORMS, WHICH HAS BEEN PROPAGATING  
SLOWLY WESTWARD OFF THE HIGHER TERRAIN TO THE NORTH AND NORTHEAST OF  
SAFFORD, HAS SHOWN NOTABLE RECENT WEAKENING AFTER BECOMING FAIRLY  
VIGOROUS. IT SEEMS UNLIKELY THAT IT WILL MAKE IT TO THE LOWER  
DESERTS, WHERE THE HOT AND DEEPLY MIXED BOUNDARY-LAYER REMAINS  
CHARACTERIZED BY RATHER WEAK INSTABILITY. HOWEVER, BASED ON LATEST  
MESOANALYSIS, BOUNDARY-LAYER INSTABILITY EAST AND SOUTH OF THE THE  
TUCSON VICINITY MAY BE SUFFICIENT TO MAINTAIN CONTINUING CONVECTIVE  
DEVELOPMENT AND A SOUTHWESTWARD PROPAGATION OF THE SOUTHERN FLANK OF  
THE COLD POOL OVER THE NEXT FEW COUPLE OF HOURS.  
 
LATER THIS EVENING, AS OUTFLOW EMANATING FROM AN EVOLVING CLUSTER  
SOUTH OF THE INTERNATIONAL BORDER INTERACTS WITH THE OUTFLOW  
APPROACHING FROM THE NORTHEAST, THERE APPEARS POTENTIAL FOR  
INCREASING THUNDERSTORM DEVELOPMENT ACROSS THE INTERNATIONAL BORDER  
VICINITY NEAR/SOUTH OF TUCSON. IF THIS OCCURS, IT APPEARS THAT  
LOW-LEVEL THERMODYNAMIC PROFILES MAY STILL BE CONDUCIVE TO STRONG TO  
SEVERE OUTFLOW SURFACE GUSTS.  
 
..KERR.. 08/05/2026  
   
..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT  
 
ATTN...WFO...EPZ...TWC...  
 
LAT...LON 31960873 31480901 30850917 30070952 30091036 31001148  
31821153 32001038 32331018 32710998 32690968 32290934  
31960873  
 
MOST PROBABLE PEAK WIND GUST...65-80 MPH  
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN  
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