719  
ACUS03 KWNS 060731  
SWODY3  
SPC AC 060730  
 
DAY 3 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
0230 AM CDT THU MAY 06 2021  
 
VALID 081200Z - 091200Z  
 
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY AFTERNOON  
INTO SATURDAY NIGHT ACROSS PARTS OF CENTRAL AND EASTERN KANSAS INTO  
NORTHERN OKLAHOMA...  
   
..SUMMARY
 
 
STRONG TO SEVERE THUNDERSTORM DEVELOPMENT IS POSSIBLE ACROSS PARTS  
OF THE CENTRAL AND SOUTHERN GREAT PLAINS ON SATURDAY. SOME OF THESE  
STORMS WILL BE ACCOMPANIED BY THE RISK FOR LARGE HAIL, STRONG WIND  
GUSTS, AND PERHAPS A COUPLE OF TORNADOES.  
   
..SYNOPSIS
 
 
MODELS INDICATE THAT BLOCKING WILL REMAIN PROMINENT WITHIN THE  
LARGE-SCALE PATTERN THROUGH THIS PERIOD AND BEYOND, AND THERE IS  
CONSIDERABLE SPREAD EVIDENT AMONG THE VARIOUS MODELS CONCERNING THIS  
EVOLUTION, PARTICULARLY WITH REGARD TO THE SMALLER-SCALE  
DEVELOPMENTS. IN GENERAL, IT APPEARS THAT ONE INITIAL HIGH CENTER,  
OVER THE LABRADOR SEA VICINITY, WILL BEGIN TO SHIFT/REDEVELOP  
EASTWARD TOWARD SOUTHERN GREENLAND, AS STRONG LOWER/MID TROPOSPHERIC  
CYCLOGENESIS PROCEEDS EAST OF THE NORTH ATLANTIC COAST INTO THE  
CANADIAN MARITIMES.  
 
WHILE A DEVELOPING MID-LEVEL LOW BECOMES INCREASINGLY PROMINENT NEAR  
THE CANADIAN MARITIMES, AN INITIALLY MORE PROMINENT MID-LEVEL LOW  
IS FORECAST TO LINGER SOUTHWEST OF JAMES BAY. UPSTREAM, MODELS  
INDICATE ANOTHER MID-LEVEL HIGH WILL EVOLVE OVER NORTHERN  
SASKATCHEWAN, WHILE LARGE-SCALE MID-LEVEL RIDGING ALSO AMPLIFIES  
ACROSS THE EASTERN PACIFIC. A STRONG JET ROUNDING THE CREST OF THE  
PACIFIC RIDGING MAY CONTRIBUTE TO DIGGING MID/UPPER TROUGHING INLAND  
OF THE PACIFIC COAST, WITH BROADLY CYCLONIC DOWNSTREAM ALSO  
DEVELOPING EAST OF THE ROCKIES, INTO THE GREAT PLAINS BY LATE  
SATURDAY NIGHT.  
 
THE MOST PROMINENT SHORT WAVE PERTURBATION WITHIN THIS CYCLONIC  
FLOW, WHICH MAY EVOLVE INTO ANOTHER MID-LEVEL CLOSED LOW, APPEARS  
LIKELY TO SHIFT EAST OF THE NORTHERN U.S. INTERMOUNTAIN REGION,  
ACROSS THE NORTHERN ROCKIES. HOWEVER, ONE OR TWO SIGNIFICANT  
IMPULSES ARE FORECAST TO EMERGE FROM THE SOUTHWEST, AND CONTRIBUTE  
TO THE SUPPRESSION OF MID-LEVEL RIDGING INITIALLY ACROSS THE  
CENTRAL/SOUTHERN GREAT PLAINS, BEFORE BEGINNING TO TRANSLATE ACROSS  
AND EAST OF THE MIDDLE/LOWER MISSISSIPPI VALLEY.  
 
COINCIDING WITH THESE DEVELOPMENTS, MODELS CONTINUE TO INDICATE THAT  
MODEST SURFACE CYCLOGENESIS WILL TAKE PLACE THROUGH THIS PERIOD,  
FROM THE LEE OF THE COLORADO FRONT RANGE INTO THE CENTRAL GREAT  
PLAINS. IT APPEARS THAT ASSOCIATED STRENGTHENING OF SOUTHERLY  
LOW-LEVEL FLOW ACROSS THE SOUTHERN INTO CENTRAL GREAT PLAINS WILL  
SUPPORT A MORE RAPID RETURN OF MOISTURE EMANATING FROM A MOIST  
WESTERN GULF OF MEXICO BOUNDARY, BENEATH STEEP-LAPSE RATES  
ASSOCIATED WITH WARM ELEVATED MIXED-LAYER AIR.  
   
..PARTS OF CENTRAL AND SOUTHERN GREAT PLAINS
 
 
MODELS SUGGEST THAT THE STEEPENING LAPSE RATES AND LOW-LEVEL  
MOISTURE RETURN WILL SUPPORT THE DEVELOPMENT OF AT LEAST MODERATELY  
LARGE CAPE ON THE ORDER OF 1000-2000 J/KG, WITH HIGHEST VALUES  
FOCUSED ALONG AND EAST OF A DEVELOPING DRYLINE ACROSS THE TEXAS BIG  
COUNTRY AND WESTERN OKLAHOMA INTO A DEVELOPING WARM FRONTAL ZONE  
ACROSS CENTRAL KANSAS. ALTHOUGH THE DETAILS OF THE POTENTIAL  
CONVECTIVE EVOLUTION REMAIN UNCLEAR, THE DRYLINE, THE WARM FRONTAL  
ZONE, AND THE COLD FRONT DEVELOPING IN THE WAKE OF THE EMERGING  
CYCLONE MAY ALL BECOME THE FOCUS FOR STRONG TO SEVERE STORM  
DEVELOPMENT LATE SATURDAY AFTERNOON INTO SATURDAY NIGHT, IN THE  
PRESENCE OF STRENGTHENING LOW-LEVEL AND DEEP-LAYER SHEAR. HIGHEST  
PROBABILITIES SEEM LIKELY TO BECOME FOCUSED NEAR THE WARM  
FRONT/DRYLINE INTERSECTION, EASTWARD ALONG OR JUST SOUTH OF THE WARM  
FRONT, WHERE SUPERCELLS MAY INITIATE, BEFORE CONVECTION POSSIBLY  
GROWS UPSCALE INTO AN ORGANIZING CLUSTER. BASED ON TRENDS IN MODEL  
OUTPUT, PARTICULARLY CONCERNING POTENTIAL DESTABILIZATION, IT IS  
POSSIBLE THAT MARGINAL AND SLIGHT RISK CATEGORIES MIGHT NEED TO BE  
BUMPED UP A CATEGORY IN LATER OUTLOOKS FOR THIS PERIOD.  
 
..KERR.. 05/06/2021  
 

 
 
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