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Mesoscale Discussion 228
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MD 228 graphic

   Mesoscale Discussion 0228
   NWS Storm Prediction Center Norman OK
   0234 PM CDT Tue Mar 24 2020

   Areas affected...Parts of southwestern into middle
   Tennessee...northestern Mississippi and northwestern Alabama

   Concerning...Severe potential...Watch likely 

   Valid 241934Z - 242130Z

   Probability of Watch Issuance...80 percent

   SUMMARY...The risk for severe thunderstorms is expected to increase
   during the next few hours.  By 5-7 PM CDT, this probably will
   include potential for supercells capable of producing tornadoes,
   particularly near/northeast of Tupelo MS into areas near and
   northwest of Muscle Shoals AL, Huntsville AL and the Shelbyville,
   Tullahoma area of southern Middle Tennessee.

   DISCUSSION...As one weakening mid-level jet streak continues to
   propagate across the Mid South, toward the southern Appalachians,
   the exit region of another (70+ kt at 500 mb) is forecast to dig
   east-southeast of the Ark-La-Tex through central Mississippi by
   23-00Z.  As this occurs, weak to modest mid-level height falls
   appear likely to overspread a destabilizing boundary layer, along
   and south of a surface frontal zone now near/just north of Memphis
   TN, Muscle Shoals and Huntsville AL.

   Insolation and surface dew point increases through the lower/mid 60s
   appear to be contributing to mixed-layer CAPE in excess of 1000
   J/kg, with remaining inhibition becoming increasingly negligible. 
   In the presence of strong deep-layer shear, the environment is
   becoming conducive to organized severe thunderstorm development,
   including discrete supercells.  While the front may become a focus
   for this convective development, model output suggests additional
   discrete storm development is possible along the low-level jet axis
   extending southward across at least much of northern Mississippi.

   As a weak frontal wave redevelops eastward from parts of northern
   Arkansas into northern middle Tennessee, the latest Rapid Refresh
   forecast soundings continue to suggest that low-level hodographs
   will become most conducive to tornadic supercells near/northeast of
   Tupelo MS, into the Muscle Shoals and Huntsville TN vicinities, and
   areas near/west of Tullahoma TN by 5-7 PM CDT.  This will include
   potential for an isolated strong tornado or two.

   ..Kerr/Thompson.. 03/24/2020

   ...Please see for graphic product...


   LAT...LON   34598984 35378927 35798794 35588630 34708659 33798852
               33918977 34598984 

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