010  
ACUS03 KWNS 290716  
SWODY3  
SPC AC 290715  
 
DAY 3 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0215 AM CDT THU JUL 29 2021  
 
VALID 311200Z - 011200Z  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF  
THE CENTRAL GREAT LAKES REGION AND FROM THE OZARKS INTO THE MID  
MISSISSIPPI VALLEY...  
   
..SUMMARY
 
 
MARGINALLY SEVERE THUNDERSTORMS CAPABLE OF ISOLATED DAMAGING WINDS  
AND HAIL, WILL BE POSSIBLE ON SATURDAY ACROSS PARTS OF THE GREAT  
LAKES REGION AND FROM THE OZARKS TO THE MID MISSISSIPPI VALLEY.  
   
..GREAT LAKES
 
 
A BROAD CYCLONIC FLOW PATTERN WILL BE IN PLACE ACROSS THE  
NORTHEASTERN THIRD OF THE UNITED STATES ON SATURDAY. AT THE SURFACE,  
A COLD FRONT WILL ADVANCE SOUTHWARD ACROSS THE GREAT LAKES REGION. A  
NORTHEAST-TO-SOUTHWEST CORRIDOR OF MAXIMIZED LOW-LEVEL MOISTURE WILL  
BE IN PLACE AHEAD OF THE COLD FRONT FROM THE MID MISSOURI VALLEY  
INTO THE CENTRAL GREAT LAKES. AS SURFACE TEMPERATURES WARM  
THROUGHOUT THE DAY IN THE VICINITY OF THE FRONT, A POCKET OF  
MODERATE INSTABILITY IS EXPECTED TO DEVELOP. THE INSTABILITY AXIS  
SHOULD BE LOCATED FROM SOUTH-CENTRAL WISCONSIN INTO WESTERN LOWER  
MICHIGAN BY AFTERNOON. CONVECTION WILL LIKELY INITIATE NEAR THE  
FRONT DURING THE LATE AFTERNOON AS INSTABILITY BECOMES MAXIMIZED,  
WITH THUNDERSTORMS MOVING SOUTHEASTWARD ACROSS THE CENTRAL GREAT  
LAKES REGION. NAM FORECAST SOUNDINGS AT 21Z NEAR MILWAUKEE SUGGEST  
THAT DEEP-LAYER SHEAR WILL BE ABOUT 30 TO 35 KT, WHICH SHOULD BE  
ADEQUATE FOR AN ISOLATED SEVERE THREAT. THE STRONGER MULTICELLS  
COULD GENERATE MARGINALLY SEVERE WINDS ALONG WITH HAIL.  
   
..OZARKS/MID MISSISSIPPI VALLEY
 
 
NORTHWEST MID-LEVEL FLOW WILL BE IN PLACE ON SATURDAY FROM THE  
NORTHERN PLAINS TO THE MID MISSISSIPPI VALLEY. A SURFACE LOW AND  
ASSOCIATED COLD FRONT ARE FORECAST TO MOVE SOUTHWARD ACROSS THE  
OZARKS, CENTRAL PLAINS AND SOUTHERN HIGH PLAINS. ALONG AND SOUTH OF  
THE FRONT, SURFACE DEWPOINTS FROM THE MID 60S TO THE LOWER 70S F  
WILL LIKELY RESULT IN THE DEVELOPMENT OF MODERATE INSTABILITY BY  
AFTERNOON. THIS COMBINED WITH LOW-LEVEL CONVERGENCE ALONG THE FRONT  
WILL PROVIDE A FOCUS FOR CONVECTIVE DEVELOPMENT. THESE STORMS ARE  
FORECAST TO MOVE SOUTHWARD ACROSS CENTRAL AND SOUTHERN MISSOURI  
DURING THE LATE AFTERNOON AND EARLY EVENING. MODERATE DEEP-LAYER  
SHEAR ALONG WITH THE INSTABILITY SHOULD SUPPORT A POTENTIAL FOR  
MARGINALLY SEVERE WINDS, ESPECIALLY AS LOW-LEVEL LAPSE RATES BECOME  
STEEP.  
 
..BROYLES.. 07/29/2021  
 

 
 
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