780 
FXUS64 KMRX 131756
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
156 PM EDT Thu Aug 13 2026

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Updated at 151 PM EDT Thu Aug 13 2026

- Periods of showers and storms continue this afternoon and
  Friday. The threat of severe weather is low, but there is 
  potential for localized flooding and isolated damaging wind 
  gusts. 

- A warming trend is expected Friday into the weekend. Saturday 
  through Monday look to be the most hot and humid days. Heat 
  Advisory products may eventually be needed. 

&&

.DISCUSSION...
Issued at 151 PM EDT Thu Aug 13 2026

Today and Tonight...The regional radar mosaic reveals scattered 
showers and storms along the instability gradient from E TN and SW 
VA back toward W KY. Hi-res guidance has continued to struggle with 
this pattern largely due to the uncertainties at the mesoscale 
level. If we look further north, another MCS is tracking through 
Illinois this afternoon. This MCS should continue moving east-
southeast and remain off to the north of NE TN and SW VA. However, 
additional scattered storms may develop this afternoon and evening. 
Visible satellite imagery highlights bubbly Cu forming across much 
of the area. Forecast soundings support the potential given moderate 
instability, high PWs, and sufficient bulk wind shear across our 
area. This could support the development of a few strong to severe 
storms. Today's threat of severe weather is low, but a few storms 
may be capable of producing damaging winds, primarily across SW VA 
and NE TN. These storms will also be capable of producing heavy rain 
and localized flooding impacts, but overall our flash flood threat 
will continue to decrease heading into Friday. 

Friday through Early Next Week... An intensifying ridge axis will 
continue to build into the Tennessee Valley ahead of the weekend.
This should limit any additional MCS impacts through the weekend,
but more typical Summer diurnally driven storm chances remain in 
place. The ridge will support a warming trend through early next 
week. Our temperatures should warm well into the 90s in the 
valleys. Heat indices will approach Heat Advisory-level across our
southeastern TN counties on Friday. There is some uncertainty 
with how high the surface dew points will go Friday afternoon. 
Some guidance keeps them in the low 70s while others warm them 
into the upper 70s. A Heat Advisory appears more likely Saturday 
and Sunday, especially across SE TN, where heat indices will warm 
into the mid to upper 100s. This heat will peak Sunday & Monday 
before the ridging responsible is suppressed further west toward 
the SW CONUS. Temperatures cool back toward normal values after 
Monday as mid- level troughing sets up over the Great Lakes and NE
CONUS. This will allow for northwestern flow aloft to return with
better daily shower & storm chances mid-week. 

&&

.AVIATION...
(18Z TAFS)
Issued at 151 PM EDT Thu Aug 13 2026

Another round of SCT SHRA/TSRA is expected across eastern
Tennessee this afternoon. Do not think anything more than PROB30 
groups are warranted today due to sparse coverage. MVFR flight 
categories are expected in convection and included in the PROB30
groups. Guidance is pretty insistent on fog and low clouds 
tonight at KTRI but any lingering convective debris clouds could
impact fog development. I have dropped KTRI to MVFR vsby given the
trends in hires guidance that support clearing skies overnight.
All sites return to VFR by mid-morning on Friday. 


&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             75  96  77  97 /  10  20  10  20 
Knoxville McGhee Tyson Airport, TN  74  93  75  94 /  10  20  10  20 
Oak Ridge, TN                       74  93  75  94 /  10  20  10  20 
Tri Cities Airport, TN              70  89  71  90 /  10  30  10  60 

&&

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

$$

DISCUSSION...BH
AVIATION...BH


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