Mesoscale Discussion 0551
   NWS Storm Prediction Center Norman OK
   0758 PM CDT Sat Apr 27 2024

   Areas affected...Northern and central Illinois

   Concerning...Severe potential...Watch likely 

   Valid 280058Z - 280200Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Severe threat to increase through the rest of the evening.
   A Watch downstream of WW150 will likely to be needed.

   DISCUSSION...A line of thunderstorms is advancing north and eastward
   across southern Iowa into northeastern Missouri this evening. This
   line will eventually move into portions of northern and central
   Illinois, with potential for additional thunderstorm development out
   ahead of this line. Ahead of this ongoing activity, temperatures
   remain in the mid 70s with dew points in the low to mid-60s. MUCAPE
   around 1500-1700 J/kg is observed in objective analysis data and
   sounding data from the 00z RAOB from ILX. Marginal deep layer shear
   around 30-35 kts suggests the main threats will be damaging wind and
   hail. Ahead of the line, more discrete development aligned with the
   low-level jet axis moving across central Illinois may pose the risk
   of a tornado if this activity continues to mature, though low-level
   lapse rates may weaken and there is uncertainty regarding this
   scenario.

   ..Thornton/Smith.. 04/28/2024

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

   ATTN...WFO...LOT...ILX...DVN...

   LAT...LON   41798978 42198953 42458911 42448820 42438786 42208778
               41658786 41308807 40778852 40368873 40078901 40018972
               40059032 40059038 40229048 40479049 41798978