8/30/05 FCST: Ohio Valley/Appalachians

[Dan Robinson]

The eastern quadrants of Katrina's circulation will move into Kentucky, West Virginia, Ohio and Tennessee on Tuesday.

The threat is of course conditional on cloud cover, but my other concern is whether easterly/southeasterly upslope flow on the eastern Appalachians will trigger/enhance a more stratiform type of precip which will stream W-WNW over the threat area, suppressing insolation and precluding discrete storm modes.

 

[Andrew Khan]

Their is a lot of haze and cloud cover here in TN, and this could lead to very little instability and convection, to make the storm fire up...it needs instability, and I don't know if it can get it. Perhaps further away, in Ohio..

 

[Tyler Allison]

Nope...Northern KY here. Hazy, overcast and sticky. Local TV stations are forecasting rain but nothing severe. The only mention of severe weather is if the sky clears just before the band hits us, but nobody expects that to happen really. Lots of rain is forecasted so major fear up here is flooding. Oh..and the chemical spill in Cincinnati *sigh*

 

[Andrew Khan]

I think it's like that for most of the TN/KY Area's.

1000 J/KG in SE TN

250 J/KG in W TN and SW KY.

 

[HAltschule]

Keep in mind that you do not need much instability at all to get tornadic supercells in this kind of environment. With the dynamics in place and SRH's so high, only minimal CAPE is needed to support severe convection.

 

[nickgrillo]

The eastern quadrants of Katrina's circulation will move into Kentucky, West Virginia, Ohio and Tennessee on Tuesday.

The threat is of course conditional on cloud cover, but my other concern is whether easterly/southeasterly upslope flow on the eastern Appalachians will trigger/enhance a more stratiform type of precip which will stream W-WNW over the threat area, suppressing insolation and precluding discrete storm modes.

Yeah...

As for tomorrow, I would see another justification for a MDT risk based on the tornado threat. Once again, extremely strong low-level shear in a VERY moist boundary layer airmass associated with Katrina is giving the chance for tornadoes. Additionally, deep-layer shear is pretty favorable as well with +40KTS across the eastern half of the risk. The overall threat for tornadoes appear high across the area, but LOL, this area is bad enough for chasing... and THIS stuff is gonna make it even harder.

 

[Dan Robinson]

An interesting development is that strengthening downslope flow over the western Appalachians is assisiting in clearing out cloud cover over central WV, southwest VA, and eastern KY, which may allow for some destabilization closer to Katrina's center where shear is greater.