Latest mesoscale discussion on Severe Thunderstorm Watch #90

Severe Thunderstorm Watch #90 remains in effect for the Illinois portions of the Chicago area until 10 pm.

 

Here is the latest mesoscale discussion from the Storm Prediction Center in Norman, Oklahoma

 Mesoscale Discussion 0418
   NWS Storm Prediction Center Norman OK
   0636 PM CDT Mon May 14 2018

   Areas affected...IL...Northern IN...Southwest MI

   Concerning...Severe Thunderstorm Watch 90...



   Valid 142336Z - 150100Z

   The severe weather threat for Severe Thunderstorm Watch 90
   continues.

   SUMMARY...Some threat for locally damaging wind and marginally
   severe hail continues across WW 90. Some threat may extend
   downstream out of the watch into northern IN/southwest MI, but no
   watch issuance is expected in that area at this time.

   DISCUSSION...The earlier bow echo that moved across the St. Louis
   metro has weakened quite a bit over the past hour, as it has moved
   into a region with somewhat less instability and midlevel
   flow/effective shear. Some residual wind threat may persist in the
   short term with this system as it decays. Further north, elevated
   convection has developed north of a boundary in the Chicagoland
   area, while other storms were attempting to develop near the surface
   boundary across east-central IL. Moderate instability and somewhat
   stronger effective shear (compared to areas further south) would
   support some severe wind and hail risk with any surface-based storms
   that can become established near the boundary across northern IL.
   Any such activity would likely spread into portions of northern IN
   and southern MI with time, though at this time the magnitude of the
   threat appears too limited for downstream watch issuance.