It now seems a sure bet that the eastern Great Lakes is due for a spate of severe weather. The SPC is presently making it out to be a linear event, as is typical of cold fronts sweeping through our region, but the wind profiles suggest the possibility of supercells and tornadoes.

If you go by the present, 12Z NAM run, central Ohio appears to be the sweet spot, with a variety of parameters converging over or near a bullseye of 2,000 j/kg SBCAPE. Here are a few maps for forecast hour 21Z to give you an idea. Click on the images to enlarge them. The first shows the aforementioned SBCAPE (shaded), sea level pressure (contours), and surface wind barbs. Not a bad bit of instability if this scenario pans out.

In the second image, you can see a nice overlay of 55-60 kt 500 mb winds (shaded) over 35-40 kt 850 mb winds (contours). The wind barbs are for the 850 mb level. The H5 winds veer still further to the west. I think it’s safe to say that shear won’t be an issue, and 1 km VGP, not shown, is as high as 0.4 in the area of heightened instability. Helicity maxes are well to the north, but I wonder what kind of effective SRH we’ll wind up with where it counts.

The third map shows a Theta-e lobe pushing up into northern Ohio with a surface lifted index between -4 and -6 perched squarely over the axis. That should get the job done.

In the last map, three different significant tornado parameters–the well-known STP, the APRWX tornado index, and the Stensrud tornado risk–all converge nicely over the same spot near Newark, Ohio. Three overlays can be a bit difficult to decipher, so let me help: the STP is shaded, the APRWX is tightly contoured like an onion, and the Stensrud has broader

contours, with its highest value circling the APRWX in a yellow ring.

All this to say, Friday may have some potential. I don’t get too excited about cold front events around here–not that we have many options in the Great Lakes, but a steady diet of squall lines has a way of lowering a person’s expectations. Of course, as soon as you let down your guard, along comes the exception to prove that storms in our area can and do deliver. Maybe this round will prove to one of those occasions. We’ll find out two days hence.