As discussed in the Convective thread, this one deserves its own thread.
Things could be very interesting in the eastern half of the country tomorrow, with everything pointing to frequent thunderstorms, and even a good chance of tornadoes! Surface heating under the deepening upper trough leads to CAPE in the 500-1000J/kg range, with low eq. temperatures and strong windshear meaning frequent heavy thundery showers. The chart below shows the "Significant Tornado Parameter", which takes a lot of these parameters into account and spits out where conditions are conducive for tornadoes to develop.
I'd say ESTOFEX may give a Level 1 in their forecast later.