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.