4/13/09 FCST: IL/MO/IN/KY/TN/AL/MS/GA/FL

[John Farley]

Surprised there is no thread yet for Monday. There are two areas of possible play, along the Gulf Coast and in the Ohio Valley. Since the latter is within my chase range, I will focus on it. It is looking like a decent cold-core setup may develop in southern IL and IN and western TN and KY; and possibly extreme southeast MO. I'm not sure there is really going to be enough moisture and instability, but in these cold-core setups you don't need as much, and the shear certainly will be there. Right now I am liking the Evansville, IN area or just north, fairly close to the triple point. There is also potential south and southwest of there, but I'm a little nervous about getting stuck somewhere near initiation where you can't cross the Mississippi or Ohio River and thus would lose the storms almost as soon as you start. And perhaps being near the warm front will add a little extra spin to any storms that develop in SE IL or southern IN, so tentatively that is what I am considering, depending of course on how things are looking tomorrow morning.

 

[John Farley]

Surprised there is no thread yet for Monday.

Wouldn't you know it; I see Dave started a thread while I was typing my post. Mods, maybe you can merge these two. Thanks!

 

[John Farley]

On this evening's NAM, I see nothing to encourage me about the Ohio valley target area that looked earlier like it had some potential for tomorrow. The instability and moisture are even worse than earlier, and the upper support is more out of phase with the surface dynamics than was the case earlier. It might be better farther south where the moisture and instability may be better, but if I don't see something in the morning to change my thinking, I may sit this one out. I suppose the evening GFS could show me something more encouraging when it becomes available, but I didn't see anything in the 18Z run to get me excited. Best dynamics looked to be a little farther northeast, along the warm front from around Terre Haute to Indianapolis, but again, pretty anemic.

 

[Wes Carter]

Looking at the 06Z+15 NAM I tend to think the area around Montgomery and Birmingham show the most promise. Dewpoints show in the 60's, CAPE of 2000-2500 J/kg, Helicity of 100-200, 25-35kt LLJ, and 20kt storm motions. I'm a newb at this so feel free to tear it apart, but that's where I'm going if I can.

The thing that concerns me is the bulk shear. It looks OK to 500mb, but not any higher than that.

 

[John Farley]

I am heading for Evansville, IN. This morning's runs look a little better on warming and moisture return, and I am thinking there may be an OK cold-core play in the I-64 corridor between Evansville and Louisville. There should be enough directional shear to make it interesting if strong storms can get going. It's marginal, but I am itching for the season's first chase, and you never know what might happen with these cold-core setups.

 

[Chip Redmond]

Thanks to the dry slot that worked in behind the warm front surface heating in S IN, W KY and TN has lifted temps into the upper 60s/low 70s. Cape in this area is around 1000 j/kg right now in W KY, TN with very little cap in place. S IN is not very unstable yet with a very strong cap thanks to the cloud deck still in place. Looking at the current mesoanalysis winds don't seem to veer much with height although there is some speed shear. The Nashville 12z sounding has fairly strong directional shear and a nice hodograph and also the current mesoanalysis would have the best shear still in central TN altough there is still a thick cloud deck in place.

I would expect initiation fairly soon in W KY and TN and expect it to go linear fairly fast. The best chance for tornadic activity seems to be if there is a cell or two go up ahead of the line in TN or maybe SC KY.

Think I am going to sit this one out.


Chip

edit: seems spc agrees MD 466