October 17th Severe Weather Chances

First and foremost we want to start this off by saying we are as impressed with this as we were with the last severe chance that was highlighted for KY and TN..in other words we are not very impressed at all..
Lets look at the NAM and the GFS first before we get into any parameters..

You can see how very similar both these models are ..so similar that at 30 hrs they are almost but not quite identical...
Now lets look at HPC and how they are displaying this..

Wow if this does not look very similar to the most recent "lack of event" I am not sure what really would. Just go back to the older blog to see the similarities...

So now we need to look at Parameters and we will notice now that there are two key differences...
Key difference # 1 ..while last time was weak CAPE this time across the KY to TN region there is no Convective Available Potential energy or no fuel to be added into any trigger such as a cold front as shown above.. We will show both the NAM and the GFS...

There use to be an old saying when it came to the fast food business and that was " Where's the beef?" Well we have a new one ..." Where is the CAPE or the instability across the TN/KY region?" There is none to be found...
The other differences come in with the rest of the Parameters. While we do have High Helicity across these regions..

We are lacking completely in the EHI category..

At least where it comes to the TN/KY regions. Remember you want to see Helicity really lined up with the EHI in order to really have any type of severe event in those areas. 
So now we are looking at the following:
1. No instability 
2. No EHI
3. High Helicity...
4. No LI 
What about lift index or lift in the atmosphere?

Interesting factor here is there is no lift in the areas of Western TN or KY so that can be added above as #4.
The only favorable factor is the shear. And that is 30-35 knots but as we just seen with the last event which is very similar to this event ...shear was not enough alone to bring a severe weather event to KY and TN..

So because we have the greater parameters of CAPE and Shear and LI and EHI etc further south and west this is where we are placing the severe threat. Again in those regions there very well could be severe weather but in areas of KY and TN there really is nothing in the guidance to support severe weather. 
Could those regions see rainfall.. You betcha! Could there be Garden variety..a chance but nothing severe with no parameters really to support it...