167 
FXUS64 KMRX 211805
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
205 PM EDT Mon Sep 21 2026

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Updated at 204 PM EDT Mon Sep 21 2026

- Well above normal temperatures to persist through Tuesday. But relief
  is on the way, with a pattern change expected mid-week and much
  cooler temperatures to follow.

- Scattered to numerous showers are expected Monday through 
  Wednesday. 

- A few strong to severe storm with damaging winds could occur
  Monday, with damaging winds being the primary threat. Localized
  flooding will be possible each day through Wednesday as well. 

&&

.DISCUSSION...
Issued at 204 PM EDT Mon Sep 21 2026

Currently a few thunderstorms out there, but also some scattered 
clouds in the southern valley from morning/early afternoon 
convection. Low confidence on location and coverage of expected 
storms this afternoon as CAMs have been exceptionally poor with 
morning convection and afternoon initialization. If/when storms do
form then the atmosphere should support fairly robust 
thunderstorm growth, with the strongest storms capable of 
producing damaging winds/microbursts, small hail, and isolated 
flooding as they'll be moving very slow. A similar set up is in 
place for tomorrow as well.

On Wednesday the pattern change gets underway and we begin to see a 
break in the relentless heat. By Wednesday a rex block pattern takes 
shape as an upper ridge builds over the Canadian side of the Great 
Lakes region, and the aforementioned Ohio valley upper low deepens 
over the Ohio valley and central Appalachian region. With the upper 
low to our north and NW flow aloft, this will push the cold front 
through the southern Appalachians and allow the cooldown to begin. 
By Thursday through the weekend we should see highs topping out only 
in the 70's for every except southeast TN where they may squeak 
across the 80 degree mark. This pattern will also be fairly dry with 
a more Canadian airmass moving in.

&&

.AVIATION...
(18Z TAFS)
Issued at 204 PM EDT Mon Sep 21 2026

Another afternoon of afternoon showers and thunderstorms expected
with limited coverage. Overnight fog also expected again at TRI,
but fog density will depend on how much rain occurs.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             71  92  69  85 /  40  70  40  70 
Knoxville McGhee Tyson Airport, TN  69  89  67  81 /  40  80  70  90 
Oak Ridge, TN                       68  87  66  80 /  40  70  60  80 
Tri Cities Airport, TN              65  83  63  76 /  60  80  70  90 

&&

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

$$

DISCUSSION...99
AVIATION...99


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