318
ACUS11 KWNS 211526
SWOMCD
SPC MCD 211526
INZ000-ILZ000-211830-

Mesoscale Discussion 2239
NWS Storm Prediction Center Norman OK
0926 AM CST Thu Nov 21 2024

Areas affected...Northeast IL into extreme northwest IN

Concerning...Heavy snow

Valid 211526Z - 211830Z

SUMMARY...Snow rates of around 1 inch per hour are possible through
the morning, along with increasingly gusty winds and reductions in
visibility.

DISCUSSION...Moderate to locally heavy snow is ongoing this morning
across southeast WI and far northeast IL, immediately in advance of
a midlevel vorticity maximum and compact surface low moving
south-southwestward over Lake Michigan. This area of snow will
continue to move southward across parts of northeast IL and adjacent
parts of northwest IN through the remainder of the morning, in
conjunction with stronger ascent attendant to the midlevel vorticity
maximum.

With initially cold temperatures through a relatively deep column
(with 700 mb temps of -10 to -15 C), sufficient ascent through the
dendritic growth zone will continue to support heavier snow rates,
and 1 inch per hour rates are possible at times through late morning
into the early afternoon. In addition, as stronger low-level flow
along the western periphery of the compact cyclone over Lake
Michigan moves southward, wind gusts in excess of 30 mph will
further support reductions in visibility.

..Dean.. 11/21/2024

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

ATTN...WFO...LOT...

LAT...LON   42478835 42488784 42298770 41678732 41278724 41038759
            41178802 41518841 41958862 42298866 42418857 42478835