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