Knoxville, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

829
FXUS64 KMRX 291739
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
139 PM EDT Sun Jun 29 2025

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(This evening through Monday)
Issued at 131 PM EDT Sun Jun 29 2025

Key Messages:

1. Scattered showers and thunderstorms this afternoon will diminish
this evening, then increase again on Monday.

2. A few of the stronger storms may produce strong gusty winds, and
isolated flash flooding will be a concern in areas that see repeated
or prolonged heavy rains.

Discussion:

Isolated to scattered showers and thunderstorms this afternoon will
diminish this evening, then will increase again on Monday with
diurnal heating.  PW values this afternoon of 1.7 to 2 inches will
be around a tenth of an inch higher Monday, with locally heavy rain
rates and the potential for isolated flash flooding issues. Enough
convective energy is expected this afternoon and again Monday
afternoon for a few stronger storms with the potential for strong
gusty winds, although the threat of severe storms will be low
overall given the lack of shear and modest DCAPE values. High
temperatures will generally be around seasonal normals.


&&

.LONG TERM...
(Monday night through next Sunday)
Issued at 131 PM EDT Sun Jun 29 2025

Key Messages:

1. Numerous showers and thunderstorms Tuesday. High PW values will
lead to the potential for some heavy rain rates and flash flooding.

2. Drier conditions beginning Wednesday.

3. Near normal high temperatures Wednesday, but then a gradual
warming trend with highs around 3 to 5 degrees above normal Friday
into the weekend.

Discussion:

A shortwave trough and cold front will be approaching Tuesday and
will push across our area late Tuesday and/or Tuesday night.  Ahead
of this, we will likely see MLCAPE values in the 1500 to 2500 J/kg
range Tuesday although shear will tick a bit higher it will still be
limited (EBWD values of 10 to 20 kts are likely). We will see
numerous showers and thunderstorms, and a few storms will likely
become strong to marginally severe with damaging winds the primary
severe threat. Heavy rain rates will also be a primary concern as PW
values increase to between 1.9 and 2.2 inches which will result in
flash flooding chances across the region. Some areas could see some
3 to 4+ inch per hour rain rates in the heaviest downpours.

Most model guidance shows the front being southeast of our area by
early Wednesday. Subsidence and drier air will build in from the
northwest on Wednesday and Thursday with mostly dry conditions
expected area-wide.

By Friday upper level ridging will build in from the west along with
mostly dry and warmer conditions that will continue into the
weekend. High temperatures are expected to be around 3 to 5 degrees
above normal Friday through Sunday. There will be an increase in
chances for isolated to scattered diurnal convection by Sunday as
the ridge begins to weaken its grip.


&&

.AVIATION...
(18Z TAFS)
Issued at 116 PM EDT Sun Jun 29 2025

At the time of this update, showers and storms are already
developing around CHA and TYS with them likely to be at least in
the vicinity over the next hour or two. For TRI, this will be
delayed by a few hours. VFR is still expected to primarily
prevail, but reductions to MVFR or less can be expected if and
when they move over the terminals. Activity should decrease
overnight with potential for patchy fog in places that see rain.
But, fog was left out of the TAFs for the time being. Winds will
remain around 5 kts or less and from a westerly to southwesterly
direction.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             72  90  73  88 /  30  70  40  80
Knoxville McGhee Tyson Airport, TN  71  90  72  85 /  30  60  50  90
Oak Ridge, TN                       70  88  71  85 /  30  70  50  90
Tri Cities Airport, TN              68  88  69  82 /  30  60  60  90

&&

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

$$

SHORT TERM...
AVIATION...BW