Mesoscale Discussion 1836 NWS Storm Prediction Center Norman OK 0816 PM CDT Mon Oct 11 2021 Areas affected...northeast Illinois through northwest Indiana Concerning...Tornado Watch 521... Valid 8:16 - 8:45PM CDT The severe weather threat for Tornado Watch 521 continues. SUMMARY...While a strong wind gust or brief weak tornado cannot be ruled out with low-topped band of convection moving through northeast Illinois and northwest Indiana during the next hour. Overall threat is becoming increasingly marginal. Remaining parts of WW 251 will be allowed to expire at 9PM CDT. DISCUSSION...Overall trend has been for storms to weaken during the past hour or so as they move northeast into air that has been largely overturned by downstream convection developing along the warm conveyor belt. A band of low-topped convection from the southeast part of Chicago metro area into northwest Indiana might remain capable of producing a strong wind gust during the next hour, but the very marginal thermodynamic environment suggests the severe threat should continue to wane.