Mesoscale Discussion 0067
   NWS Storm Prediction Center Norman OK
   1118 AM CST Wed Feb 10 2021

   Areas affected...Lower Ohio River Valley

   Concerning...Freezing rain 

   Valid 101718Z - 102115Z

   SUMMARY...Freezing rain is expected to expand in coverage and
   intensity across portions of the Ohio river valley this afternoon.
   Freezing rain rates approaching 0.05 to 0.1 inches per hour will be
   possible.

   DISCUSSION...12z upper-air observations showed broad cyclonic flow
   across the northern 3rd of the CONUS with several small shortwave
   troughs embedded within this flow. Over the last 2 hours, radar data
   shows stratiform precipitation across portions of southern Illinois
   and eastern Missouri increasing in coverage/intensity likely due to
   increased isentropic and large scale ascent from one of the
   approaching shortwave troughs. Surface observations under the
   developing band of precipitation indicate freezing rain/ mist as the
   primary precipitation type across the area.

   Hi-res model guidance and observational data suggest that rain rates
   will gradually increase through the afternoon as isentropic ascent
   continues to strengthen along and north of the surface front. A few
   thunderstorms my also develop across the region with guidance
   indicating MUCAPE around 100-150 J/kg aloft. Rates may approach 0.1
   in/hr in the heaviest cores through this afternoon. Additional
   precipitation will likely expand southwestward as greater forcing
   for ascent develops aloft. Freezing rain and occasional sleet appear
   to be the most likely precipitation types through the next several
   hours given upstream and downstream RAOBS showing fairly uniform
   +1-2 C warm layers atop sub freezing surface layers.

   ..Lyons/Goss.. 02/10/2021

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

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

   LAT...LON   36968841 37008932 37509009 38058982 38718792 39058618
               39048576 38678499 38118491 37648511 37258574 37148708
               37008803 36968841