Areas affected...central and north-central IL Concerning...Tornado Watch 521... Valid 3:40PM - 5PM CDT The severe weather threat for Tornado Watch 521 continues. SUMMARY...The risk for wind damage and a couple of transient mesovortices capable of a short-lived/weak tornado, will probably maximize over the next 1-2 hours as a bowing squall line quickly moves northeastward across north-central IL. DISCUSSION...Radar mosaic shows a maturing squall line in the vicinity of a surface low over west-central IL. The airmass over the northern third of IL is moist (mid 60s surface dewpoints) but clouds have tempered overall destabilization this afternoon. Nonetheless, weak buoyancy noted in RAP forecast soundings will aid in storm vigor as the squall line moves northeast across central and northwest IL through the early evening. The primary risk will be damaging gusts in association with surging areas of the squall line, but a short-lived tornado is possible with more intense eddies/mesovortices that become sustained as this activity moves across the I-74 and I-80 corridors during the next few hours. One limitation that may limit the overall severe risk is weaker shear evident at the Davenport, IA 88D VAD and this may limit the severe risk near the MS River.