Mesoscale Discussion 757

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MESOSCALE DISCUSSION 0757 NWS STORM PREDICTION CENTER NORMAN OK 0625 PM CDT THU MAY 29 2014 AREAS AFFECTED...WRN DAKOTAS...FAR NE WY CONCERNING...SEVERE THUNDERSTORM WATCH 198... VALID 292325Z - 300030Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 198 CONTINUES. SUMMARY...TSTMS...SOME SVR...ARE EXPECTED TO PERSIST ALONG A COLD FRONT MOVING EWD ACROSS THE WRN DAKOTAS. LARGE HAIL AND DAMAGING WINDS ARE POSSIBLE. DISCUSSION...A COLD FRONT EXTENDS SWD ACROSS WRN ND AND INTO FAR NW WY. CORRIDOR OF NARROW INSTABILITY AHEAD OF THE COLD FRONT CONTINUES TO FAVOR TSTM DEVELOPMENT WITH SOME STORMS CAPABLE OF SVR HAIL NOTED ACROSS SW ND. STORMS ACROSS ND ARE EXPECTED TO CONTINUE GRADUALLY EWD INTO A MORE STABLE ENVIRONMENT. ADDITIONALLY...SLOW EWD MOTION -- RESULTANT FROM THE BULK SHEAR VECTOR ORIENTATED PARALLEL TO THE FRONTAL BOUNDARY -- WILL RESULT IN THE COLD FRONT UNDERCUTTING ONGOING STORMS. THESE FACTORS WILL LIKELY RESULT IN GRADUALLY WEAKENING STORMS. MOST MODEL GUIDANCE CORROBORATES THIS SCENARIO ACROSS ND. FARTHER S ACROSS WRN SD AND FAR NERN WY...TSTMS ARE EXPECTED TO PERSIST WITH SOME INCREASE IN COVERAGE POSSIBLE OVER THE NEXT HOUR OR TWO. FRONTAL BOUNDARY EXTENDS MORE SWWD ACROSS CNTRL WY WITH THE BULK SHEAR VECTOR ACROSS THIS AREA ALIGNED LESS ALONG THE BOUNDARY THAN FARTHER N. AS A RESULT...A SUPERCELL OR TWO MAY BE ABLE TO PERSIST LONGER ACROSS THIS REGION. HOWEVER...LOW-LEVEL MOISTURE HAS MIXED OUT ACROSS THIS REGION....LIMITING OVERALL INSTABILITY AND STORM STRENGTH. CURRENT RADAR IMAGERY SUGGESTS MOST OF THE ONGOING ACTIVITY REMAINS ALONG OR JUST BEHIND THE BOUNDARY. ..MOSIER.. 05/29/2014