ZCZC SPCSWOMCD ALL
ACUS11 KWNS 221517 
SPC MCD 221517 
MIZ000-OHZ000-INZ000-ILZ000-221915-

Mesoscale Discussion 0083
NWS Storm Prediction Center Norman OK
0917 AM CST Mon Jan 22 2024

Areas affected...portions of eastern/northeastern IL...northern
IN...far southern MI and far northwest OH

Concerning...Freezing rain 

Valid 221517Z - 221915Z

SUMMARY...Light to moderate freezing rain is expected through the
morning hours with rates of 0.01-0.03 in/hr possible. Some
mixed-phase precipitation is also possible early.

DISCUSSION...As of 15 UTC, regional radar mosaic imagery and surface
observations showed a broad area of light to moderate wintry
precipitation across parts of northeastern IL. Over the last hour,
automated reports of unknown precipitation type and freezing rain
have gradually become more numerous as the precipitation has
expanded over an air mass with surface temperatures in the mid to
upper 20s F. Driven primarily by low-level warm advection, light to
moderate precipitation is expected to continue to move
east/northeast this morning. Light snow has been observed across
parts of southwest lower MI and northwest IN. However, observed and
modified model soundings show an elevated warm nose of 1-2 C between
1-2 km AGL will gradually advect northeastward over the next few
hours. While some snow and sleet are possible ahead of the main area
of precipitation, gradually deepening of the elevated warm layer to
near 600-800 m will favor a transition to predominately freezing
rain.

Rain rates of 0.01-0.03 in/hr are possible above favorable surface
temperatures for rapid ice accretion. The most likely corridor for
impactful freezing rain appears to be from northeastern IL into
northwest IN and far southwest lower MI through this morning. Hi-res
CAM guidance has been poor thus far in handling the evolution of the
precipitation field. While low-level warm advection may wane
slightly through the day, observed low and mid-level ascent appears
strong enough to continue to support precipitation into the early
afternoon. Given the cold surface temperatures and melting layer
aloft, freezing rain appears likely.

..Lyons.. 01/22/2024

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

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

LAT...LON   40838938 41758869 42098776 42128766 42468617 42558533
            42498463 42328424 42038397 41788398 41508429 41208475
            40658550 39528694 39268766 39638852 39848874 40838938 

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