The tornado outbreak is well underway.
We have a Particularly Dangerous Situation Tornado Watch in effect until 6pm in the Mid-Mississippi Valley.
And, an “ordinary” tornado watch that includes Huntsville and eastern Tennessee. Damaging tornadoes have already occurred in this region. Understand Alabama’s Limestone Correctional Institute is reported to have taken a “direct hit.”
The NWS has expanded the High Risk of tornadoes between now and 6am Saturday. See posting below for explanation.
The index of significant tornadoes (≥F2 intensity) is already very high with values of 5 and 6 as of 10 am (latest data available). I use a threshold of 2 on this. Any thunderstorms in these areas will be very conducive for producing violent tornadoes.