Mesoscale Discussion 0486 NWS Storm Prediction Center Norman OK 0451 PM CDT Tue Apr 28 2020 Areas affected...Portions of southern Chicagoland and northeastern east-central Illinois Concerning...Severe potential...Watch unlikely Valid 282151Z - 282345Z Probability of Watch Issuance...20 percent SUMMARY...A storm or two capable of large hail and damaging wind gusts will be possible for the next 1-2 hours. A storm currently in La Salle County may impact portions of southern Chicago and its suburbs by 530 PM CDT. A storm or two may also exit WW 152 and impact portions of east-central Illinois. Given limited buoyancy downstream of this activity, no WW is expected. DISCUSSION...A marginally organized supercell moving east through northern La Salle County will eventually impact portions of the south side of Chicago and its suburbs. 1 inch hail and estimated 60 mph winds have already been reported with this storm. Deep-layer shear of around 40 kts, per KLOT VAD, is sufficient to continue storm oganization. MLCAPE is around 500-1000 J/kg on objective mesoanalysis and dwindles with eastward extent. Though other instances of marginally severe hail and damaging wind gusts are possible, the threat should remain isolated and last for the next 1-2 hours. Farther south, another better organized supercell moving into Marshall County may eventually move out of WW 152 and similarly post a large-hail and damaging-wind threat. Buoyancy is slightly better farther south, but storms in this location will similarly encounter a less favorable thermodynamic environment to the east. A WW is not expected.