DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0744 AM CDT TUE MAY 22 2007
   
   VALID 221300Z - 231200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS FROM SE SD ACROSS CENTRAL NEB
   TO WRN KS THIS AFTERNOON INTO TONIGHT...
   
   ...SYNOPSIS...
   A MID LEVEL LOW OVER WRN WY WILL LIFT NEWD TOWARD WRN ND AS AN
   EMBEDDED SPEED MAX ROTATES EWD/NEWD AROUND THE SERN PERIPHERY OF THE
   LOW TO WRN NEB BY THIS EVENING...AND THE CENTRAL/ERN DAKOTAS
   OVERNIGHT.  IN ADVANCE OF THIS MID LEVEL WAVE...A SURFACE CYCLONE IN
   CENTRAL SD WILL DEVELOP NNEWD ACROSS ERN ND TO SE MANITOBA BY THIS
   EVENING...WHILE A TRAILING COLD FRONT MOVES EWD ACROSS THE DAKOTAS
   AND SEWD ACROSS NEB/NW KS.  A SEPARATE LEE CYCLONE IN ERN CO THIS
   MORNING WILL DEVELOP SWD TOWARD NE NM/NW TX PANHANDLE BY TONIGHT AS
   SWLY FLOW ALOFT INCREASES OVER THE CO FRONT RANGE.  THE COLD FRONT
   ACROSS THE DAKOTAS/NEB...BACK TO THE TRIPLE POINT IN NW KS...WILL BE
   THE PRIMARY FOCUS FOR STRONG/SEVERE THUNDERSTORM DEVELOPMENT THIS
   AFTERNOON INTO TONIGHT.
   
   ...CENTRAL NEB TO WRN KS THIS AFTERNOON INTO TONIGHT...
   LOW-LEVEL MOISTURE /BOUNDARY LAYER DEWPOINTS NEAR 60 F/ IS SPREADING
   NWD FROM OK/ERN TX PANHANDLE TO KS ON A 35-50 KT LLJ THIS
   MORNING...IN THE WAKE OF CONVECTIVE CLUSTERS THAT DISSIPATED
   OVERNIGHT.  THE REMAINING DEBRIS CLOUDINESS FROM OVERNIGHT
   CONVECTION WILL GRADUALLY DIMINISH TODAY ACROSS KS/NEB...WHICH WILL
   ALLOW SURFACE TEMPERATURES TO WARM INTO THE 80S NEAR AND S/SW OF THE
   TRIPLE POINT THIS AFTERNOON.  MLCAPE VALUES SHOULD INCREASE TO
   1500-2500 J/KG IN CONJUNCTION WITH THE LOW-LEVEL WARMING AND
   MOISTENING BENEATH A PLUME OF STEEP MID LEVEL LAPSE RATES.  THE
   WEAKER CONVECTIVE INHIBITION AND STRONGER LOW-LEVEL ASCENT ARE
   EXPECTED NE OF THE TRIPLE POINT FROM NW KS INTO CENTRAL NEB ALONG
   THE COLD FRONT THIS AFTERNOON/EVENING.
   
   WHILE THE LOW LEVELS DESTABILIZE DURING THE AFTERNOON...DEEP LAYER
   VERTICAL SHEAR WILL INCREASE NEAR AND JUST NE OF THE TRIPLE
   POINT...ON THE NOSE OF THE MID-UPPER JET EJECTING NEWD OVER THE
   CENTRAL HIGH PLAINS.  MEANWHILE...L0W-LEVEL SHEAR WILL INCREASE
   AGAIN THIS EVENING IN ASSOCIATION WITH A STRENGTHENING LLJ ACROSS
   KS/OK.  THE NET RESULT WILL BE A FAVORABLE ENVIRONMENT FOR
   SUPERCELLS WITH VERY LARGE HAIL AND A FEW TORNADOES FROM LATE
   AFTERNOON INTO THE LATE EVENING.  THE WINDOW OF OPPORTUNITY FOR
   DISCRETE STORMS COULD BE LIMITED BY DEEP LAYER FLOW/SHEAR SOMEWHAT
   PARALLEL TO THE COLD FRONT...AND PERSISTENT MOISTURE INFLUX INTO THE
   FRONTAL ZONE WHICH WILL FAVOR UPSCALE GROWTH INTO A LINEAR MCS
   TONIGHT ACROSS NRN KS/NEB.
   
   ...EXTREME SW KS TO THE ERN TX PANHANDLE THIS EVENING...
   THE DRYLINE IS FORECAST TO REMAIN CAPPED THROUGH MOST OF THE PERIOD.
    HOWEVER...AFTERNOON TEMPERATURES IN THE MID-UPPER 80S ALONG THE
   DRYLINE MAY RESULT IN SUFFICIENT MIXING TO SUPPORT THE DEVELOPMENT
   OF AN ISOLATED STORM OR TWO FOR A COUPLE OF HOURS THIS EVENING INVOF
   THE ERN TX PANHANDLE.  IF DEEP CONVECTION DOES FORM...INSTABILITY
   AND VERTICAL SHEAR SHOULD BE SUFFICIENT FOR SUPERCELLS WITH LARGE
   HAIL BEFORE THE BOUNDARY LAYER COOLS/STABILIZES LATE THIS EVENING.
   
   ...NE SD INTO ERN ND/NW MN TODAY...
   PRIOR CONVECTION HAS EXHAUSTED MUCH OF THE INSTABILITY ACROSS
   ND...WITH ONLY A NARROW CORRIDOR OF RICHER MOISTURE FROM NE SD INTO
   SE ND AND NW MN.  A WELL-DEFINED MCV IS MOVING TOWARD THIS AREA FROM
   CENTRAL SD...AND CONVECTION WITH THIS FEATURE WILL LIKELY REMOVE
   MUCH OF THE LINGERING INSTABILITY DURING THE FIRST HALF OF THE DAY. 
   THEREFORE...ANY SEVERE STORM THREAT THIS AREA SHOULD REMAIN
   MARGINAL.
   
   ...E/SE TX AREA TODAY...
   ONGOING CONVECTIVE CLUSTER OVER SE TX WILL MOVE EWD TOWARD SW LA
   TODAY IN CONJUNCTION WITH A SERIES OF VORTICITY MAXIMA WITHIN THE
   SUBTROPICAL JET.  HOWEVER...THE STORMS WILL LIKELY MOVE E OF THE
   PRIMARY MOISTURE/INSTABILITY AXIS RELATIVELY EARLY IN THE DAY...THUS
   THE THREAT FOR SEVERE STORMS SHOULD QUICKLY DIMINISH THIS MORNING.
   
   ..THOMPSON/TAYLOR.. 05/22/2007
   
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