SPC MD 33

MD 0033 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHERN AND CENTRAL IL...NORTHERN IN...AND SOUTHERN LOWER MI

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

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

ATTN...WFO...IWX...IND...LOT...ILX...DVN...

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

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