276 
FXUS64 KMRX 081829
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
229 PM EDT Sat Aug 8 2026

...New DISCUSSION...

.KEY MESSAGES...
Updated at 229 PM EDT Sat Aug 8 2026

- Showers and thunderstorms will be around each day through next 
  Saturday, with the afternoons generally the period of most 
  activity. 

- There will be potential for a few storms to become strong to 
  severe each afternoon at least through Tuesday (and possibly 
  beyond), with damaging winds and localized flooding the main 
  threats.

- Temperatures will be generally not be far either side of normal
  for this time of year. 

&&

.DISCUSSION...
Issued at 229 PM EDT Sat Aug 8 2026

A weak mid/upper level circulation near the AR/TN border is 
drifting slowly east. A weak midlevel deformation zone out ahead 
of it is enhancing shower and thunderstorm activity over our area 
today. Flow is weak and PWAT values high, and like recent days 
these slow-moving storms can produce locally heavy
rainfall/flooding and strong gusty winds. Sunday looks similar as
the weak mid/upper low transitions to an open wave and continues 
to drift east. Weak flow, PWAT values in the 1.8 to 2 inch range 
and MLCAPE values generally in the 1000-1500 J/kg range point to 
another day with a potential for a few storms to become strong to 
marginally severe, with strong winds the primary threat along with
localized flooding.

Models have not been consistent on how quickly the trough will exit 
east, but the trend has it moving east more quickly leading to the 
pattern becoming more northwesterly aloft for Monday and Tuesday 
with a broad upper trough centered to our east and a broad high 
pressure ridge to our west. This brings slightly drier air aloft to 
the area, steeper mid-level lapse rates, and afternoon MLCAPE values 
more in the 1500 to 2000 J/kg range. Shear still generally looks 
weak, but given the better thermodynamic profile storms Monday and 
Tuesday could pose a slightly higher threat of becoming strong to 
severe with damaging winds still the primary threat.  

Models diverge for the later periods with cluster analysis showing 
one camp of ensemble members keeping us in more of a northwest flow 
aloft while another camp builds the ridge east with the jet 
displaced further north, thus confidence on the details is low. 
Convective coverage will be influenced by which camp is more correct 
as well as any short waves moving through the flow. Ensembles 
suggest at least a slight uptick in shear especially north by mid-
week which is more consistent with the northwest flow camp of which 
some (including the latest runs of the operational GFS) bring a 
significant wave and a cold front into and through the area late in 
the work week. Overall, daily chances for showers and storms can be 
expected, but specifics on timing and severe/flooding potential will 
have to wait until we get closer.    


&&

.AVIATION...
(18Z TAFS)
Issued at 104 PM EDT Sat Aug 8 2026

Scattered showers and thunderstorms around this afternoon will be
included as prob30 thunder groups all sites. Fog/low cig 
development potential tonight will be influenced by the as yet
unknown details of rain occurrence/timing/amounts at each site, 
but will carry a tempo group for MVFR vsby in fog at CHA for late 
tonight where the ensemble data suggests the highest chance. Other
than with the fog and any showers/storms, VFR conditions are 
expected. 

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             72  91  73  91 /  20  40  10  70 
Knoxville McGhee Tyson Airport, TN  71  90  72  90 /  20  30  10  40 
Oak Ridge, TN                       71  89  72  90 /  20  30  10  40 
Tri Cities Airport, TN              68  87  69  88 /  20  20  20  30 

&&

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

$$

DISCUSSION...99
AVIATION...99


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