561 
FXUS64 KMRX 010535
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
135 AM EDT Sat Aug 1 2026

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Updated at 129 AM EDT Sat Aug 1 2026

- Showers and storms will move in today and continue tonight into 
Sunday. A few storms may become strong to severe, especially over 
the Plateau and the southern Tennessee valley late Saturday into 
Saturday night. Localized flooding will also be possible. 

- Scattered showers and storms can be expected each day Monday
  through Friday, especially during the afternoon hours.

&&

.DISCUSSION...
Issued at 129 AM EDT Sat Aug 1 2026

Model run to run agreement is still poor overall, so the details 
even in the short term are not as certain as would be preferred. 
However, the basic pattern is not much in doubt with an upper low 
moving out of the mid Mississippi Valley and into the Ohio River 
Valley/southern Great Lakes region through Sunday. A cold front will 
approach us from the west and eventually move into/through our area 
Saturday night and/or Sunday. The details of how strong and the 
exact track of both the low pressure system and how quickly the 
front will move into and through our area have been handled very 
inconsistently by the models.  However, there is high confidence 
that showers and thunderstorms will move into our area later tonight 
and this morning as moisture surges in with the increasing southerly 
flow and divergence aloft ahead of the upper trough.  This 
thunderstorm activity is expected to be sub-severe, as CAPE will be 
modest and the convection likely elevated at first.  

Clouds and convection during the day Saturday will impact how much 
instability develops, but it currently looks like at least moderate 
MLCAPE of 1000 to 1500 J/kg will develop over western areas during 
the afternoon.  By late today/this evening the front will be moving 
into middle TN, and the CAMS generally show additional convection 
firing ahead of the front and moving east toward our area. Models 
have around 20 to 30 kts of effective shear which given at least 
moderate instability would support organization of the convection 
and the potential for some strong to severe storms with damaging 
winds the primary threat. The best low level shear looks to stay to 
our north and northwest, but there is sufficient low level shear and 
clockwise curvature of the hodograph that a tornado cannot be ruled 
out especially if the CAPE and shear potential is maximized.  The 
severe potential should be highest for our Plateau and southern 
valley counties where the convection will arrive first and surface 
CAPE will have less time to decrease from loss of solar heating. The 
low level jet will be out of the south and southeast across the 
mountains Saturday and Saturday night, with downslope flow into the 
valley. In fact, we will likely see gusty winds in the usual higher 
mountain elevation and foothill areas with some mountain wave 
enhancement of the winds, although it generally should stay sub-wind 
advisory level. Given this downslope flow as well as the later 
arrival of the convection in our central and northern/eastern areas, 
it is not surprising that the CAMS quickly weaken the convection as 
it progresses further east across our area. 
  

In addition to the severe threat, given the abundant moisture with 
PWAT values near or exceeding 2 inches for Saturday into Saturday 
night very heavy rainfall and localized flooding will also be 
possible, especially across the Plateau and southern portions of our 
area.   

Depending on how quickly the front clears our area, a marginal 
severe storm threat may continue into Sunday over our northeast 
counties ahead of the boundary where significant effective shear and 
instability will be lingering ahead of the front. Behind the front, 
any showers and storms should be more isolated to scattered and 
weaker Sunday. 

The later periods continue to feature significant chances for 
showers and storms each day Monday through Friday but with the 
highest chances early in the week in response to a meandering weak 
upper low that most models leave behind over the region. Models 
still disagree on placement and movement of the upper low, and some, 
while in the minority, would suggest a quicker return to drier and 
warmer conditions. We will have to see as we get closer.

&&

.AVIATION...
(06Z TAFS)
Issued at 129 AM EDT Sat Aug 1 2026

Multiple rounds of showers and storms will move through the region
starting this morning. The best chance for thunder will be in the
late afternoon and evening hours. TRI will see less activity. The
highest confidence of rain and thunder will be in the evening
hours at all terminals. MVFR CIGs are possible in the morning
hours mainly near CHA where showers will likely start earlier in
the morning. Otherwise, VFR conditions are expected outside of
heavy rain. Southerly winds will be gusty at times.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             86  71  86  70 /  80  80  40  10 
Knoxville McGhee Tyson Airport, TN  87  72  86  69 /  70  80  60  30 
Oak Ridge, TN                       85  70  85  68 /  80  90  60  30 
Tri Cities Airport, TN              86  69  84  67 /  30  60  80  40 

&&

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

$$

DISCUSSION...99
AVIATION...99


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