400  
ACUS03 KWNS 220649  
SWODY3  
SPC AC 220648  
 
DAY 3 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0148 AM CDT TUE MAY 22 2018  
 
VALID 241200Z - 251200Z  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE  
EASTERN DAKOTAS AND PARTS OF MN...  
   
..SUMMARY
 
 
ISOLATED SEVERE THUNDERSTORMS ARE EXPECTED ACROSS PORTIONS OF THE  
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY.  
   
..NORTHERN PLAINS/UPPER MS VALLEY
 
 
NOTABLE SHORT-WAVE TROUGH IS EXPECTED TO EJECT ACROSS THE NORTHERN  
HIGH PLAINS, FLATTENING THE UPPER RIDGE OVER THE DAKOTAS DURING THE  
LATTER HALF OF THE PERIOD. LATEST MODEL GUIDANCE CONTINUES TO  
SUGGEST CONVECTION WILL LIKELY DEVELOP DOWNSTREAM OF THIS FEATURE IN  
MULTIPLE PHASES. EARLY-DAY CONVECTION SHOULD BE DRIVEN BY LOW-LEVEL  
WARM ADVECTION AND THIS ACTIVITY IS EXPECTED TO DEVELOP WITHIN A  
CORRIDOR OF ELEVATED INSTABILITY THAT WILL BE ADEQUATELY SHEARED FOR  
SOME ORGANIZATION AND POTENTIAL CLUSTERING. HOWEVER, MORE  
SIGNIFICANT THUNDERSTORM DEVELOPMENT IS POSSIBLE LATER IN THE DAY  
ALONG/AHEAD OF A PRE-FRONTAL TROUGH THAT SHOULD ORIENT ITSELF ACROSS  
THE EASTERN DAKOTAS. MODELS ARE CONSISTENT IN ALLOWING APPRECIABLE  
HEATING/DESTABILIZATION ACROSS THE LOWER RED RIVER VALLEY AND ROBUST  
THUNDERSTORM DEVELOPMENT SEEMS PLAUSIBLE BY LATE AFTERNOON. WILL  
INTRODUCE 5% SEVERE PROBS FOR THIS REGION TO ACCOUNT FOR THIS  
LATE-DAY DEVELOPMENT. SOME THOUGHT WAS GIVEN TO 15% SEVERE ACROSS  
THIS REGION BUT DEEP-LAYER SHEAR IS NOT FORECAST TO BE PARTICULARLY  
STRONG AND HEIGHT FALLS ARE EXPECTED TO BE SOMEWHAT WEAK AHEAD OF  
THIS FEATURE. HOWEVER, SEVERE PROBS MAY BE INCREASED CLOSER TO THE  
EVENT IF CONFIDENCE IN THIS SCENARIO INCREASES.  
 
..DARROW.. 05/22/2018  
 

 
 
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