493 
FXUS64 KMRX 111740
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
140 PM EDT Thu Jun 11 2026

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Updated at 137 PM EDT Thu Jun 11 2026

- Pretty high risk of severe storms area wide tomorrow. Damaging 
  winds are the most likely hazard, and could be quite strong 
  (possibly as high as 80mph). Hail and flash flooding are also a 
  concern.

- Unsettled pattern continues through the middle of next week.


&&

.DISCUSSION...
Issued at 137 PM EDT Thu Jun 11 2026

The primary concern for the next few days is the chance of severe 
storms tomorrow afternoon across our forecast area. As such, the 
discussion will focus on that almost exclusively.

Shortwave energy will move from the central plains to the western 
Great Lakes region today and tonight, driving a cold front 
southeastward towards the southern Appalachian region tomorrow. 
Ahead of the front, widespread convection expected across the 
Midwest later on this afternoon. This activity will lay out an 
outflow boundary that will be pushing into the Cumberland Plateau 
tomorrow afternoon, sparking off widespread strong to severe storms 
across East Tennessee. There are some timing uncertainties here, and 
potential failure modes, but it appears likely that we see very 
strong/severe storms tomorrow capable of damaging winds a bit higher 
than what we'd normally expect in this area.

Hazards:

Tomorrow looks primarily like a damaging wind threat. However, there 
is also a threat of severe sized hail as well as flash flooding. 
They're less a threat than damaging winds but I can't ignore them. 
The tornado risk looks negligible due to lack of shear. Going back 
to the damaging wind threat, the model consensus seems to be that 
surface based CAPE values will exceed 2,500 - 3,000 J/kg tomorrow 
afternoon. This is backed by roughly a 70-80 percent chance in 
probabilistic guidance of exceeding 2,000 J/kg sfc CAPE. Meanwhile, 
downdraft CAPE looks to exceed 1,000 J/kg, with plenty of mid level 
dry air intrusion and very strong lapse rates. Lack of shear 
(effective bulk shear values of less than 15-20kt) means that the 
initial convective mode will likely wind up being cellular or 
multicell clusters, but this may transition into some quasi-linear 
state later in the evening as convection becomes more widespread. As 
such, the damaging wind risk will be sporadic initially. I'd expect 
the potential for 70-80mph winds given the instability and resulting 
storms heights we'll be dealing with. Speaking of instability and 
storm heights, let's talk about hail. The lack of shear means less 
organized convection which will work against severe sized hail, as 
will the fairly high freezing levels. But the forecast instability 
means there's at least a mentionable risk of some severe sized hail. 
I would not be surprised to see some 1" hail reports of perhaps 
slightly larger. 

As for the heavy rain and flash flooding threat, this should be 
isolated but it certainly exists. PWATs are high, and the strong to 
severe nature of storms tomorrow means that heavy rainfall rates 
will be possible. The limiting factor I think will be the lifespan 
of any given storm and whether or not we have any training effects. 
Mean winds aren't perfectly aligned with the incoming outflow 
boundary and front, but they're close, which may support some 
training effects. Lack of shear means that storm lifespans will be 
shorter (more on the summertime cellular end of the spectrum versus 
supercells) so I think that we'll need some degree of training 
effects to really get any significant flooding. 

Timing and Uncertainties:

Current timing favors storm initiation over the northern Cumberland 
Plateau around 2-3 PM EDT roughly. I lump timing and uncertainties 
in together here because storm initiation is almost certainly going 
to be along the incoming outflow boundary and there is some 
disagreement on when that makes it in and exactly when/where storms 
initiate. Most guidance favors it arriving in the plateau during 
that 2-3 PM EDT window, with storm initiation occurring at that 
time. But some guidance has initiation occurring squarely in the TN 
valley and it doing so a couple of hours later. The plateau 
oftentimes convects as early in the afternoon as the higher terrain 
of the Smokies does, so I would expect that early afternoon time to 
be the most likely. Most guidance moves storms off to our southeast 
by 9-10 PM EDT as well, so it won't linger into the overnight hours.


As for the remainder of the forecast period, this front pushes south 
of us on Saturday. We may get a reprieve from the humidity in the 
northern areas, and also some dry conditions that day, but an 
incoming shortwave in the zonal flow aloft may spark off some 
additional storms at least near/south of the I-40 corridor. Better 
chances exist on Sunday though as another, stronger impulse moves 
through. Moving into early next week, upper flow becomes SELY over 
the deep south and southern Appalachian region Monday through 
Wednesday. We'll continue to monitor this as this pattern will 
support widespread heavy rains and the potential for flooding. The 
question is really, where will that set up. There remains quite a 
bit of uncertainty there. Current trends show the heavy rains 
staying mostly to our south, but we're close enough to keep an eye 
on it. 

&&

.AVIATION...
(18Z TAFS)
Issued at 137 PM EDT Thu Jun 11 2026

We do have some ISOLD SHRA in the TN valley this afternoon, one of
which was near KTYS as of the writing of this. Threw in some VCSH
at TYS and CHA to account for current radar trends but those
should die off in the next couple of hours. Otherwise, VFR flight
categories should prevail through the 18z period. Widespread 
SHRA/TSRA will be moving into the TN valley shortly after the end
of the period though. 


&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             73  91  71  90 /   0  60  20  10 
Knoxville McGhee Tyson Airport, TN  73  91  69  88 /   0  80  40  10 
Oak Ridge, TN                       71  90  66  87 /   0  80  20   0 
Tri Cities Airport, TN              70  90  65  87 /  10  80  50  10 

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

DISCUSSION...CD
AVIATION...CD


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