MESOSCALE DISCUSSION 0760
   NWS STORM PREDICTION CENTER NORMAN OK
   0206 PM CDT THU MAY 12 2011
   
   AREAS AFFECTED...S-CNTRL/ERN NEB...FAR NRN KS
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 121906Z - 122100Z
   
   THE THREAT FOR SVR STORMS...INCLUDING TORNADIC SUPERCELLS...IS
   INCREASING. CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED THROUGH
   THE AFTERNOON FOR THE POTENTIAL ISSUANCE OF A WW.
   
   SFC ANALYSIS AT 18Z DEPICTS A QUASI-STATIONARY FRONT...MAINTAINED BY
   AN EXPANSIVE STRATUS DECK TO ITS WNW...EXTENDING WSWWD FROM W-CNTRL
   IA TO ERN NEB 25 ENE OFK TO A TRIPLE POINT 30 WNW EAR. FROM THE
   TRIPLE POINT...AN OCCLUDED FRONT EXTENDS SWWD TO A 1006-MB SFC LOW
   25 ESE MCK...WHILE A PACIFIC COLD FRONT ARCS SEWD TO THE NEB/KS
   BORDER 35 N CNK AND FARTHER S INTO CNTRL KS. BEHIND THE PACIFIC
   FRONT...A CONTINENTAL COLD FRONT ARCS SWD FROM THE SFC
   LOW...EXTENDING TO 35 S RSL AND FARTHER SW INTO THE HIGH PLAINS.
   
   EAST OF THE PACIFIC FRONT OVER SERN NEB AND FAR NERN KS...MODEST
   BOUNDARY LAYER MOISTURE -- I.E. SFC DEWPOINTS FROM THE UPPER 50S TO
   LOWER 60S -- BENEATH THE NRN EXTENT OF A PLUME OF 700-500 MB LAPSE
   RATES AOA 7 C/KM IS RESULTING IN MODERATE POTENTIAL INSTABILITY --
   I.E. MLCAPES OF 1000-1500 J/KG. MEANWHILE...THE INFLUENCE OF
   MID-LEVEL ASCENT OVER THE ERN PERIPHERY OF A 500-MB VORT MAX
   CENTERED OVER SWRN NEB...COMBINED WITH STEEPENING LOW-LEVEL LAPSE
   RATES...IS NOTED BY THE DEVELOPMENT OF A HIGHER-BASED CU FIELD
   BETWEEN THE PACIFIC AND CONTINENTAL FRONTS PER RECENT VISIBLE
   SATELLITE IMAGERY. AS THIS ASCENT SHIFTS INTO THE MORE UNSTABLE AIR
   EAST OF THE PACIFIC FRONT...WHERE LITTLE CINH REMAINS PER MODIFIED
   RAPID REFRESH FORECAST SOUNDINGS...CONVECTION MAY DEVELOP DURING THE
   NEXT FEW HOURS. A ZONE OF ENHANCED SSWLY MID-LEVEL FLOW EAST OF THE
   VORT MAX IS SUPPORTING EFFECTIVE BULK SHEAR MAGNITUDES TO 35 KT.
   BOTH MULTICELLS AND SUPERCELLS COULD EVOLVE IN THIS AREA...WITH A
   THREAT FOR DMGG WINDS AND LARGE HAIL. THE THREAT FOR TORNADOES WILL
   BE GREATEST NEAR AND JUST SOUTH OF THE STATIONARY FRONT...WHERE SFC
   FLOW WILL BE RELATIVELY BACKED.
   
   ANOTHER AREA FOR ENHANCED TORNADO POTENTIAL COULD EVOLVE BETWEEN THE
   TRIPLE POINT AND SFC LOW...INVOF THE OCCLUDED FRONT. IN THIS
   REGION...BOUNDARY LAYER MOISTURE...ALBEIT RELATIVELY MORE LIMITED --
   I.E. SFC DEWPOINTS IN THE LOWER AND MIDDLE 50S -- COMPARED TO
   FARTHER EAST ARCS SWWD TOWARD THE SFC LOW. DESPITE THE MORE MEAGER
   MOISTURE...COOLER TEMPERATURES ALOFT ARE FOUND IN THIS REGION IN
   CLOSER PROXIMITY TO THE AFOREMENTIONED VORT MAX. THIS IS ENHANCING
   THE DEGREE OF LOW-LEVEL BUOYANCY WHERE THE FLOW IS NOTICEABLY MORE
   BACKED PER HASTINGS VWP...AND A LOCAL JUXTAPOSITION OF 0-3 KM MLCAPE
   VALUES OF 100-150 J/KG WITH STRONG SFC VORTICITY IS NOTED NEAR AND
   NE OF THE SFC LOW. THIS SET-UP WILL BE CONDUCIVE FOR COLD-CORE AND
   ASCENDING TORNADOGENESIS PROCESSES WITH LOW-TOPPED...SHALLOW
   CONVECTION.
   
   ..COHEN.. 05/12/2011
   
   
   ATTN...WFO...FSD...OAX...TOP...GID...LBF...GLD...
   
   LAT...LON   39829608 39919850 39830012 40450031 41149978 41889842
               42309669 40939567 39829608