015 
FXUS64 KMRX 011913
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
313 PM EDT Sat Aug 1 2026

...New DISCUSSION...

.KEY MESSAGES...
Updated at 245 PM EDT Sat Aug 1 2026

- Additional showers and storms are expected this afternoon and
  evening. A few storms may become strong to severe, especially 
  over the Plateau and the southern Tennessee valley this evening.
  Localized flooding will also be possible.

- Isolated damaging winds and flooding will be possible with
  additional storms across far northeast Tennessee and southwest
  Virginia Sunday afternoon.

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

&&

.DISCUSSION...
Issued at 245 PM EDT Sat Aug 1 2026

Upper level pattern consists of a shortwave diving through 
Mississippi River Valley towards the Ohio and Tennessee Valley 
region. A warm front lifting through the CWA has been the driving 
force for showers and a few thunderstorms this morning and early 
afternoon. While a few isolated showers can be noted behind the main 
rain shield, some clearing is present across portions of central 
Tennessee into northern Alabama and along the Cumberland Plateau. A 
trailing cold front is expected to progress through the region this 
evening, with additional shower and storm development along and 
ahead of this front. There are still some discrepancies among CAMs 
in how well organized or the exact coverage area of convection along 
this feature, however, one trend that catches my eye is that of the 
NAMs.

Latest surface observations show temperatures rebounding into the 
low to mid 80s in the southern valley and plateau, upper 70s on the 
northern plateau, but remaining in the low 70s in portions of the 
central valley and eastward. The NAM seems to depict a trend in 
storm coverage that best aligns with where precip has lingered 
longest this afternoon... one where storms that develop over middle 
Tennessee persist into the Plateau, but as the activity progresses 
further east into the CWA, the focus is generally along and south of 
I-40 where better destabilization occurs among higher theta-e 
advection. 

Overall, HREF depicts around 1500-2000 J/kg of MLCAPE and effective 
shear between 20 and 25kts as this activity is expected to take 
place. Additionally, PWAT will be well into the 90th percentile. 
This will lead to damaging winds and isolated flooding as the 
primary hazards. However, the shear is just strong enough that a low 
tornado risk will is in place, primarily along the Cumberland 
Plateau and southern Valley where the greatest destabilization has 
occurred. Of course any storm that has enough rotation for a 
potential tornado could also exhibit small hail as well. Activity 
will gradually trend downward in intensity around midnight or 
shortly thereafter. 

As we head into Sunday afternoon, a few additional showers and 
storms may develop along the slowly progressing cold front. Latest 
trend in CAMs favors far northeast Tennessee and southwest Virginia 
for additional convective initiation. Strong effective shear and 
increasing DCAPEs will support at least a isolated wind damage 
and flooding threat where storms train along the boundary. 
Depending on how much clearing takes place and resulting CAPE 
profiles, cannot rule out some small hail as well. 

An upper low is expected to be cutoff as we head into the new work 
week, which will continue to promote daily chances of showers and 
storms among slightly below normal temperatures. Some
deterministic models begin to eject the low late week, with a 
downward trend in precip chances and slight warming trend. 

&&

.AVIATION...
(18Z TAFS)
Issued at 156 PM EDT Sat Aug 1 2026

Rain shield is moving from the central to eastern portions of the
forecast area at this time. The back edge should be through TYS
within the next hour or so, and estimated around 20/21Z for TRI.
Reduced visibility and occasional cig reductions cannot be ruled
out with this activity. Unsettled pattern continues as additional
showers and storms develop and advect west to east this evening
into the overnight hours. Thunderstorm chances are greatest at
CHA/TYS. Lingering MVFR conditions are possible behind the
activity overnight. However, the lowest uncertainty is at TRI due
to expected downsloping. MOS and LAMP guidance is aggressive with
low cigs while HREF probabilities are less than 20% at TRI. 

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             72  86  70  85 /  90  30  20  70 
Knoxville McGhee Tyson Airport, TN  72  86  70  84 /  80  40  40  80 
Oak Ridge, TN                       71  84  69  84 /  90  40  40  80 
Tri Cities Airport, TN              69  83  68  82 /  70  80  60  70 

&&

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

$$

DISCUSSION...KRS
AVIATION...KRS


--- MBSE BBS v1.1.7.2 (Linux-x86_64)
 * Origin: Outpost BBS * Johnson City, TN (618:618/1)