06/15/10 FCST: IN/IL

[ericjkelly]

Finally a day around home to maybe see some decent storm events.

I am a little concerned that the MCS will get through my neck of the woods too late to really see anything. Both the NAM and GFS show the bulk of activity pushing through the area late tonight (Eastern Indiana).

Both the Shear and Helicity seem enough to get some rotation in some of the embedded supercells in the line.

I am a newbie and still learning....Am I reading this right?

 

[Matt Hunt]

Just getting ready to post on this event! I'm pretty new as well at forecasting, but today looks like a decent setup for some tornadoes, with CAPE at 2000-3000 j/kg along the IL/IN border, and bulk shear at 40-50 kts around 5pm EDT, when I'm expecting things to fire. 0-1km EHI is at 2.0 along the border from Vincennes, IN up to Danville, IL at 7pm. I think this will be the area to be in during the evening hours, and as you said will not reach eastern IN until later in the evening.

My main concern at the moment is the convection currently ongoing in Central IL. However, satellite images show noticeable clearing behind this line, so the atmosphere should recover quickly.

Rob Gardner and I are planning on targeting Chrisman, IL around 4pm.

 

[Andrew Pritchard]

Copy and paste from my blog earlier this morning...

This is a somewhat late notice, but I like the odds at a couple tornadoes in central parts of Illinois today, likely around the Interstate 72 corridor. My target triangle at the moment for a few reports would be from Bloomington to Springfield to Mattoon this afternoon.

A decaying MCS and associated shortwave is approaching from Missouri this afternoon. Associated with this wave will be deep layer shear on the order of 40 knots with the H5 jet streak. Thunderstorms currently over the target area are hindering destabilization at the moment, but in their wake clearing skies should allow for a quick recovery and moderate destabilization. Ahead of the wave, surface winds should increase slightly and turn out of the south and even southeast further north at about 10 knots. This, along with a strengthening LLJ should supply the low level shear needed for rotating thunderstorms, and the 40-50 knot streak at H5 should be more than enough for sustained updrafts and supercell storms.

Storms should begin to develop early in the afternoon in southwest Illinois from around Quincy to St. Louis. Organization may take some time, but storms should reach severe levels by the time they reach the Interstate 55 corridor from Springfield south, as they move northeast. An upscale growth into an MCS is eventually likely, thus this early period from Springfield to Interstate 57 approximately is where tornadoes would be most likely with any storm. Low level shear should be greatest along Interstate 72, so I'd likely try and hug this area.

I'm still on the fence as to whether I will chase this event or not, but at this point am leaning more towards a yes. I'll likely make a decision by noon, and head south towards Bloomington to adjust from there, likely south a little more.

EDIT: After writing that blog post, I've started really watching that OFB for possible enhanced rotation with any storm that goes down that way today towards I-70. May adjust south a bit, but still eyeballing the I-72 corridor at this point.