ZCZC SPCSWOMCD ALL
ACUS11 KWNS 172332 
SPC MCD 172332 
INZ000-KYZ000-ILZ000-MOZ000-180530-

Mesoscale Discussion 1891
NWS Storm Prediction Center Norman OK
0532 PM CST Sat Dec 17 2016

Areas affected...southwestern Indiana...southern Illinois...far
southeastern Missouri...and far northern/western Kentucky

Concerning...Freezing rain 

Valid 172332Z - 180530Z

SUMMARY...The freezing rain threat will increase from north to south
this evening across the discussion area, with icing potential
extending into far northwestern Kentucky around 04-05Z.

DISCUSSION...A broken band of convection continues along a strong
cold front located from central Ohio (near Dayton) southwestward to
western Kentucky (near Paducah) and on to near Little Rock,
Arkansas.  North of this boundary, strong low-level cold advection
was resulting in falling surface temperatures, while precipitation
resulting from the broken band of convection was developing
northward atop the cold low-level airmass.  Areas of freezing rain
were beginning to develop in far southern Illinois over the past
hour concurrent with surface temperatures falling to/below freezing,
and models/observations suggest that this area of freezing rain will
expand southeastward through the discussion area.  Convective
enhancement of precipitation rates appears possible too, as
observations/point forecast soundings suggest some weak mid-level
instability remaining in the region even as the stronger band of
convection moves gradually eastward.  The freezing rain potential
should exist through at least 05Z and will be dependent on likely
increase in convection across Arkansas, which will gradually migrate
toward the discussion area over the next few hours.

..Cook.. 12/17/2016

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LMK...IND...PAH...ILX...LSX...

LAT...LON   38078985 38508905 39088817 39528713 39528642 39278624
            38648639 38018681 37438786 37028877 36748933 36668998
            36719042 36959057 37589023 38078985 

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