MESOSCALE DISCUSSION 0904
   NWS STORM PREDICTION CENTER NORMAN OK
   0451 PM CDT TUE MAY 13 2008
   
   AREAS AFFECTED...PARTS OF NE OK THRU MUCH OF ERN KS/WRN MO
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 132151Z - 132315Z
   
   SEVERE THREAT APPEARS TO BE INCREASING...AND A WW MAY BE NEEDED
   SOON.
   
   BREAKS IN CLOUD COVER HAVE ALLOWED FOR INCREASING INSOLATION WITHIN
   A NARROW LOW-LEVEL PRE-FRONTAL THERMAL RIDGE EXTENDING ROUGHLY FROM
   THE INTERSTATE 35 CORRIDOR OF CENTRAL OK NORTHEASTWARD TOWARD THE
   KANSAS CITY MO METROPOLITAN AREA.  COUPLED WITH NORTHWARD BOUNDARY
   LAYER MOISTURE RETURN THROUGH THE MID/UPPER 60S ALONG THIS
   AXIS...THE ENVIRONMENT IS BECOMING MODERATELY UNSTABLE.  MIXED LAYER
   CAPE IS EXPECTED TO INCREASE INTO THE 1000-2000 J/KG RANGE THROUGH
   THE REMAINDER OF THE AFTERNOON.  AND...LOWER/MID TROPOSPHERIC
   COOLING...NOW UNDERWAY...WILL CONTRIBUTE TO DIMINISHING INHIBITION.
   
   MODEL GUIDANCE...INCLUDING THE RUC...SUGGEST THAT A SERIES OF
   MID-LEVEL JET STREAKS ARE IN THE PROCESS OF DEVELOPING NORTHEASTWARD
   WITHIN A BROAD BELT OF SOUTHWESTERLY FLOW AHEAD OF THE SOUTHERN
   BRANCH TROUGH OVER THE SOUTHWESTERN STATES...AND THE NORTHERN BRANCH
   TROUGH PROGRESSING INTO THE UPPER MISSISSIPPI VALLEY.  AND...THERE
   ARE INDICATIONS THAT A COUPLING OF TWO OF THESE FEATURES WILL
   CONTRIBUTE TO INCREASING LIFT ACROSS EASTERN KANSAS INTO WESTERN
   MISSOURI THROUGH THE 14/00-03Z TIME FRAME.
   
   THIS SHOULD AID CONVECTIVE DEVELOPMENT...WHICH NOW SEEMS GRADUALLY
   UNDERWAY.  AS INHIBITION CONTINUES TO ERODE...STRONG DEEP LAYER
   SHEAR WILL BE SUPPORTIVE OF AT LEAST SIGNIFICANT MID-LEVEL UPDRAFT
   ROTATION.  A FEW SUPERCELLS ARE POSSIBLE...WITH THE RISK FOR LARGE
   HAIL/DAMAGING WINDS...PERHAPS ISOLATED TORNADOES.
   
   ..KERR.. 05/13/2008
   
   
   ATTN...WFO...SGF...EAX...TSA...TOP...ICT...OUN...
   
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