SPC MESOSCALE DISCUSSION 0185 FOR NE AR/SE MO/SRN IL/WRN KY AND TN
   CONCERNING...SEVERE THUNDERSTORM POTENTIAL...
   
   VALID 151611Z - 151900Z
   
   AREA IS BEING MONITORED FOR POSSIBILITY OF INCREASING SEVERE
   THREAT.
   
   ON WESTERN PERIPHERY OF SERN U.S./WESTERN ATLANTIC SURFACE RIDGE...
   MODELS SUGGEST MODERATELY STRONG LOW-LEVEL JET WILL PERSIST ACROSS
   THE LOWER MISSISSIPPI VALLEY THROUGH THE DAY...WITH 40+ KT SPEED
   MAXIMUM OVER SOUTHEAST ARKANSAS SLOWLY SHIFTING EASTWARD INTO
   NORTHWEST TENNESSEE.  LOW-LEVEL WARM ADVECTION/ISENTROPIC LIFT ON
   NOSE OF THIS JET IS CURRENTLY SUPPORTING INCREASING CONVECTIVE
   DEVELOPMENT FROM PARTS OF THE OZARKS INTO THE MIDDLE MISSISSIPPI
   RIVER VALLEY.  THIS IS JUST TO THE NORTHEAST OF CAPPING ELEVATED
   MIXED LAYER AIR WHICH HAS ADVECTED OFF THE MEXICAN PLATEAU...AS FAR
   NORTHEAST AS THE ARKLATEX.  STEEP LAPSE RATES ON EDGE OF THIS CAP
   MAY BE CONTRIBUTING TO CAPE UP TO 1000 J/KG...SUPPORTIVE OF
   INCREASING SEVERE THREAT IN FAVORABLY SHEARED ENVIRONMENT.  PRIMARY
   SEVERE THREAT APPEARS TO BE LARGE HAIL IN STRONGER CELLS DEVELOPING
   ABOVE RELATIVELY COOL/STABLE SURFACE-BASED AIR MASS.  ACTIVITY IS
   EXPECTED TO SLOWLY INCREASE IN COVERAGE THROUGH THE AFTERNOON HOURS
   ...AHEAD OF A COUPLE OF SHORT WAVES LIFTING OUT OF LARGER-SCALE
   WESTERN U.S. TROUGH.
   
   ..KERR.. 03/15/02