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Mesoscale Discussion 33
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   Mesoscale Discussion 0033
   NWS Storm Prediction Center Norman OK
   0340 PM CST Wed Jan 11 2017

   Areas affected...Portions of northern and central IL...northern
   IN...and southern Lower MI

   Concerning...Severe potential...Watch unlikely 

   Valid 112140Z - 120015Z

   Probability of Watch Issuance...5 percent

   SUMMARY...A few strong thunderstorms could affect the area through
   the evening hours, and an isolated severe storm cannot be ruled out.
   Watch issuance is not anticipated.

   DISCUSSION...Surface low pressure analyzed over northeast MO will
   continue tracking northeastward along a quasi-stationary boundary
   extending across northern IL and Lake MI. Meanwhile, moisture return
   continues south of the synoptic boundary, with middle/upper 50s
   dewpoints south of a secondary boundary analyzed from near the
   surface low to southern IN. As warm advection preceding the surface
   low (reflected by 2-hour pressure falls on the order of 2-3 mb)
   interacts with increasing low-level moisture, convection should
   continue to modestly intensify into the evening hours -- primarily
   focused along a consolidating cold front trailing to the southwest
   of the surface low, and within the warm-advection plume preceding
   the low.

   Given the presence of 40-60 kt of effective bulk shear, and ample
   low-level directional/speed shear, a few organized, strong
   thunderstorms may spread northeastward/east-northeastward through
   the evening hours -- especially after 2230Z. Generally small hail
   will be the primary concern, though a locally strong wind gust could
   occur along the cold front given convective momentum transport
   amidst strong low-level wind fields. An isolated severe thunderstorm
   cannot be ruled out. However, relatively scant boundary-layer
   moisture and limited surface heating beneath modest midlevel lapse
   rates should minimize buoyancy, while convective inflow remains
   elevated above a stable boundary layer. These factors will greatly
   minimize overall severe potential.

   ..Cohen/Kerr.. 01/11/2017


   LAT...LON   39608968 40119034 40839033 41398946 41788759 41958579
               41678524 40828561 39918743 39608968 

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