275  
ACUS02 KWNS 261722  
SWODY2  
SPC AC 261722  
 
DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1222 PM CDT WED JUL 26 2017  
 
VALID 271200Z - 281200Z  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NEW ENGLAND  
TO OK...  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE  
NORTHERN/CENTRAL HIGH PLAINS...  
   
..SUMMARY
 
 
SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS A LARGE PORTION OF THE  
US THURSDAY. A FEW STORMS MAY PRODUCE GUSTY WINDS ACROSS THE  
CENTRAL/NORTHERN HIGH PLAINS AND FROM OKLAHOMA TO SOUTHERN NEW  
ENGLAND.  
   
..FRONTAL ZONE FROM OK TO NY
 
 
HIGH-PW PLUME WILL BE GRADUALLY SHUNTED SOUTHEAST ACROSS THE  
CONTIGUOUS US DURING THE DAY2 PERIOD AS A FRONTAL ZONE PROGRESSES TO  
A POSITION FROM LAKE ON, SOUTHWEST ACROSS IN INTO NORTHERN OK BY  
18Z. THIS HIGH PW PLUME WILL BE CHARACTERIZED BY POOR LAPSE RATES  
WITH EMBEDDED LEFT OVER CONVECTIVE MCVS. EACH OF THESE FEATURES WILL  
BE DIFFICULT TO PREDICT WITH ANY CERTAINTY BEYOND A FEW HOURS AND  
12Z MODEL GUIDANCE IS NOT PARTICULARLY USEFUL IDENTIFYING ANY  
NOTABLE FEATURE THAT COULD AID ORGANIZED STRONG CONVECTION. EVEN SO,  
SHORT-WAVE TROUGHING WILL SHIFT ACROSS ON INTO QC WITH THE SOUTHERN  
EXTENT OF THIS FEATURE EXPECTED TO EXTEND TO A LATITUDE OF SOUTHERN  
NEW ENGLAND. DEEP-LAYER SHEAR WILL BE NOTABLY STRONGER ACROSS THE  
NORTHEASTERN US AHEAD OF THIS FEATURE BUT FORECAST INSTABILITY  
APPEARS INADEQUATE FOR MORE THAN MARGINAL SEVERE AT THIS TIME. GUSTY  
WINDS ARE THE PRIMARY THREAT WITH CONVECTION ACROSS THIS REGION.  
 
FARTHER SOUTHWEST FROM THE TN VALLEY INTO THE SOUTHERN PLAINS,  
STRONG BOUNDARY-LAYER HEATING WILL BE FOCUSED ALONG THIS CORRIDOR  
WITH THE STEEPEST LAPSE RATES OCCURRING OVER THE SOUTHERN PLAINS  
WHERE SURFACE TEMPERATURES SHOULD SOAR TO NEAR 100F. WITH PW VALUES  
EXPECTED TO BE NEAR 2" ACROSS THIS REGION A FEW DAMAGING DOWNBURSTS  
SEEM POSSIBLE.  
   
..NORTHERN/CENTRAL HIGH PLAINS
 
 
MODEST DEEP-LAYER SHEAR WILL DEVELOP ACROSS THE HIGH PLAINS FROM  
EASTERN MT INTO NORTHEAST CO AS UPPER RIDGING REMAINS ANCHORED OVER  
THE ROCKIES. AFTERNOON CONVECTION THAT EVOLVES ACROSS THIS REGION  
WILL DO SO WITHIN AN ENVIRONMENT FAVORABLE FOR DEEP ROTATION AND A  
FEW SLOW-MOVING SUPERCELLS COULD DEVELOP DURING THE LATE  
AFTERNOON/EARLY EVENING, THOUGH FORECAST LAPSE RATES ARE NOT  
PARTICULARLY STEEP FOR THIS REGION AND BUOYANCY MODEST AT BEST. FOR  
THESE REASONS IT APPEARS ANY SUPERCELLS THAT EVOLVE SHOULD PROVE  
MARGINALLY SEVERE WITH HAIL/WIND POSSIBLE.  
 
..DARROW.. 07/26/2017  
 

 
 
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