Update: 4:00 PM
While the atmosphere is more than ready to handle storm development with CAPE in the 1,800-2,500 J/kg range, we are lacking the lift to get showers/storms going. While it’s certainly not impossible for a storm or two to bubble up, the time is running out. The ingredients will be highest around 5-7 PM and should one develop, it should be able to get this act together quickly.
This latest sounding from Crossville on 20z from the HRRR model shows that the parameters are more than enough. But the “IF” factor is; can we get one going? And that remains to be seen.
Mostly clear skies have taken over west of Morristown and will continue to spread east.
First Post:
The area remains under a Marginal/Slight risk for severe weather this evening as storm development will be possible later on.
What We Know
Looking at currently forecasted soundings (at 20z) we can see that there is little to absolutely no CAP in place over the plateau which will make it easy for storm development later on. A somewhat significant increase in CAPE over the valley and plateau of 1,500-2,200 J/Kg by 20z shows that any showers/storms that can develop will be in a favorable environment with dewpoints in the 60s and air temperatures in the upper-60s to lower/mid-70s. Now looking towards NE TN and SW VA we can see a (very) low supportive environment for rotation in thunderstorms at 16z – bringing a very low (but non-zero) risk of tornados in the area. Aside from development, the environment will be favorable and supportive for updrafts that can bring a hail threat area-wide which holds the risk of hail up to quarter size. The best supportive time according to models will be between 18-0z this afternoon before mostly diminishing overnight.
All said, the intensity of any storm development will depend on the location and environment.