2018-04-03 EVENT: AR, MS, TN, KY, IN, OH

[Mike Johnston]

Let's start a thread for a possible event covering portions of the southeast and Ohio valley on April 3rd.

There should be a broad area of 60+ dewpoints over this general area with a narrower area of 65+ dewpoints within the broad area.

A 996mb surface low should begin the day in SE KS and move northeastward to IN as the day progresses and deepen to 993mb.

A secondary jet streak is evident in the upper levels from east TX to IN.

Instability is highest in eastern AR into western TN with helicity highest just north of there.

One of my favorite parameters, the axis of high theta-e air looks to be nosing in to western TN. Overall it looks to me like that will be the area of greatest potential: just SE of the confluence of the Mississippi and Ohio rivers. I like a specific target of Martin, TN.

 

[Royce Sheibal]

I've never seen the 90% line on SPC's Sig Tor Ingredients. Ever. I didn't even know it existed. SW Indiana looking rough this afternoon.

 

[Andy Wehrle]

I've never seen the 90% line on SPC's Sig Tor Ingredients. Ever. I didn't even know it existed. SW Indiana looking rough this afternoon.

It was probably there on April 27, 2011 given how eye-popping all the parameters were that day. SIGTOR isn't perfect, but it's a good bet there will be a few dangerous storms across the Ohio and mid-MS valleys today.

 

[Quincy Vagell]

The greatest short-term supercell tornado threat (as well as large to very large hail) appears to be maximized from far southern IL into southeastern MO, northeastern AR, western TN and southwestern KY. Not only are deep layer shear vectors (generally westerly) making favorable angles with the cold front (in the ballpark of 45 degrees), but low-level shear is also favorable, not to mention steep lapse rates in excess of 8 C/km, via mesoanalysis. Storms in this environment should remain at least semi-discrete, if not discrete, with the potential for a few longer-lived tracks.

It also happens that this area is arguably the most chaser friendly in the Mississippi Valley (outside of interior IL), given relatively flat terrain and decent road networks.