Thursday, April 2, 2015 5:52 PM

Tornado Risk Later Today and Tonight

Matthew Holliday

A window is going to open up later this afternoon into the evening hours for an enhanced tornado threat to develop from northeastern Oklahoma, southeastern Kansas, southwestern and southern Missouri and northwestern and northern Arkansas. The tornado threat will not be exclusive to these regions; however, this is the area in the great threat zone.

A stationary frontal boundary is currently located across the Southern Plains into the Mid-Mississippi Valley. The atmosphere has continued to become unstable as breaks in the clouds have allowed the sun to heat up the surface. The biggest question has been whether or not the heating of the day would be sufficient enough to erode away a capping inversion (cap). A cap is a layer of warmer air on top of cooler air located in the boundary layer (the layer of the atmosphere in contact with the surface). When this occurs, that air gets trapped and can’t rise. When that lowest layer sufficiently warms, then the air is able to rise, condense, and form clouds and storms.

Wind shear (changing wind speed and direction with height) is currently sufficient along with several other ingredients. I made a tornado risk zone map to give you an idea of who will have the greatest risk of seeing a tornado. Keep in mind that areas just outside the outlined region also need to keep an eye on everything.

Firsthand Weather tornado map

In addition to a tornado threat, damaging winds and hail will be a possibility with any storm that develops. Storms are already firing from the Southern Plains to the Mississippi Valley, Tennessee and Ohio Valley, and Southeast. The environment is very moist and humid over a very expansive warm-sector. Many people are either currently being or will be impacted by storms today.

I posted SPC’s convective outlook below. If anything changes, I’ll post an updated map.

spc convective outlook