462 
FXUS64 KMRX 110632
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
232 AM EDT Sat Jul 11 2026

...New DISCUSSION...

.KEY MESSAGES...
Updated at 225 AM EDT Sat Jul 11 2026

- Multiple waves of showers and storms may move through the 
  region through Monday. A Flood watch remains in effect through 
  Sunday evening.

- A few strong to severe storms will be possible each day. The 
  primary threat will be gusty winds.

- More typical summer weather Tuesday onwards with normal 
  temperatures and only a low PM chance of thunderstorms.


&&

.DISCUSSION...
Issued at 225 AM EDT Sat Jul 11 2026

More uncertainty than usual surrounds the next 48 hours or so I 
think. The main issue is the principal shortwave that may or may 
not enhance our coverage of thunderstorms is all by its lonesome 
in the Ohio River Valley region, without any longwave trough to 
assist storminess. Because of this, between the departure of the 
last shortwave earlier in the week and the arrival of this 
upcoming one on Sunday, our storm coverage and intensity really 
hasn't been impressive nor predictable. 

The other "fun" thing that crops up every year is model performance 
in weakly forced environments aka most of summer. Thursday evening 
the CAMs were not initializing well at all with the storms upstream 
of us in western and central Kentucky. The 01z HRRR for today keeps 
the small popcorn stuff currently on radar going then brings one, 
two, three versions of dying MCSs into the area by midday today. The 
overall QPF output in that time span isn't so bad, which I think 
matches with the more consistent take from consensus that the storm 
complexes, should they occur, will be struggling with either diurnal 
timing or each other's wakes. The rest of the 00z suite, meanwhile, 
really doesn't have that much in the way of consistency on timing or 
breadth of convection. The 18z REFS is actually more aggressive with 
high neighborhood probabilities of 4" rainfall occurrence, so the 
flood watch isn't without merit, just this forecaster is not overly 
confident in verifying it, especially given sub-par storms the past 
two days. The avenue to getting flooding would be actually receiving 
several waves of broad thunderstorms that deliver increasingly 
higher rainfall totals. If we don't see this today, then well we're 
not likely to flood.

This all brings me to storm severity. The REFS ensemble mean 
probability for 1000J of surface CAPE is 40% over the Plateau 
counties during the peak heating and 70% in Chattanooga today. 
Knoxville and locations to the northeast are unlikely to reach that 
threshold. This would make severe wind I think unlikely Knoxville 
and those east and northeast, with damaging winds, if any, relegated 
to the Plateau counties and maybe the southern TN valley. This 
assumes quite a bit regarding evolution of the weather the next 12 
or so hours but it's what probability is here for. Damaging winds 
remain the only severe hazard expected today, buoyed a bit by 20 to 
25 knots of effective shear. Should any severe storms manifest, 
those storms would also be most likely to be carrying the most 
torrential rains. 

Heading into Sunday and Monday we remain unsettled thanks to our 
shortwave cutting off and getting stuck. Wouldn't say I have much 
confidence here other than the shortwave will definitely be hanging 
around to at least provide some impetus for showers and storms. 
Storm severity also might be lesser, depending on the degree of 
destabilization we can acquire. After that the shortwave will go 
where all good cutoff lows go, west, and it will slowly dissipate 
underneath the impressive Great Plains ridge. We will in turn see 
our rain chances decrease for the remainder of the week, with only 
diurnal summer isolated to scattered activity possible with 
generally light flow and mild ridging aloft.
&&

.AVIATION...
(06Z TAFS)
Issued at 1233 AM EDT Sat Jul 11 2026

There will be showers and thunderstorms across the area during the
period, although timing of the thunderstorms at any given site is
still very uncertain at this time. Will carry vcsh for much of the
period and try to time periods of the highest probability for 
storms with tempo and prob30 thunder groups, but thunder will be 
possible outside of these times as well. Conditions are expected 
to be mainly VFR outside of the storms. However, a more persistent
period of MVFR cigs is likely to occur at TRI later tonight into
the early morning hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             91  72  86  70 /  80  70  70  70 
Knoxville McGhee Tyson Airport, TN  86  70  84  69 /  90  70  70  70 
Oak Ridge, TN                       86  70  84  68 /  90  80  80  70 
Tri Cities Airport, TN              81  66  82  66 /  80  90  70  50 

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...Flood Watch through Sunday evening for Cherokee-Clay.

TN...Flood Watch through Sunday evening for Anderson-Bledsoe-Blount 
     Smoky Mountains-Bradley-Campbell-Claiborne-Cocke Smoky 
     Mountains-East Polk-Grainger-Hamblen-Hamilton-Hancock-
     Hawkins-Jefferson-Johnson-Knox-Loudon-Marion-McMinn-Meigs-
     Morgan-North Sevier-Northwest Blount-Northwest Carter-
     Northwest Cocke-Northwest Greene-Northwest Monroe-Rhea-
     Roane-Scott TN-Sequatchie-Sevier Smoky Mountains-Southeast 
     Carter-Southeast Greene-Southeast Monroe-Sullivan-Unicoi-
     Union-Washington TN-West Polk.

VA...Flood Watch through Sunday evening for Lee-Russell-Scott VA-
     Washington VA-Wise.

&&

$$

DISCUSSION...Wellington
AVIATION...99


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