Knoxville, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

011
FXUS64 KMRX 191756
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
156 PM EDT Sat Jul 19 2025

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

.SHORT TERM...
(This evening through Sunday)
Issued at 156 PM EDT Sat Jul 19 2025

Key Messages:

1. Ongoing showers and storms will need to be monitored for heavy
rainfall rates and potential flooding in areas that have received
excessive rainfall the past few days.

2. Additional showers/storms expected in northern sections on
Sunday, with a continued potential for flooding and strong/severe
wind gusts.

Discussion:

A very moist air mass with PW values over 2 inches and tall, skinny
CAPE profiles in model soundings will favor showers and
thunderstorms that produce heavy rainfall rates through the
remainder of the afternoon and evening. The main area of concern for
localized flooding issues will be in SW VA, where there has been
excessive rainfall over the past few days, leading to saturated
soils and high levels of creeks and streams. FFG in that area is
around 1-1.25 inches. A few strong wind gusts are possible with the
heavy downpours inthe strongest storms, but this should be very
isolated. The activity will likely persist past sunsset in northern
sections as a shortwave trough (associated with storms over southern
IL/IN) will track across the area between 00-06Z.

Behind the shortwave trough passage on Sunday, we will get a little
more amplification of the mid/upper flow, with a northwesterly
direction in the 850-500 mb layer. PW drop a little, in the 1.8-2.0
range, but there may be training of cells in parts of the area that
have received the most rainfall recently, in SW VA. So flooding will
continue to be a concern in that area for at least another day. The
slight drying/cooling aloft (and higher DCAPE near 900 J/kg) may
pose a slightly better chance of seeing strong to severe wind gusts
on Sunday afternoon/evening.

&&

.LONG TERM...
(Sunday night through next Saturday)
Issued at 156 PM EDT Sat Jul 19 2025

Key Messages:

1. Scattered storms will continue through much of the extended
period with a low chance of strong wind gusts and localized flooding
with the storms.

2. Hot and humid conditions persist through the period with heat
index values of 100-105 degrees across the Valley next week.

The pattern aloft will amplify on Monday as the high pressure ridge
over LA will build northward, and a trough deepens off the East
Coast and western Atlantic. The NW flow through the mid and upper
levels will push a surface front toward our area on Monday, which is
expected to be the focus for shower/storms across KY and the OH
Valley area. The NW flow will steer this activity into our northern
sections Monday evening. Low levels remain quite moist, and MLCAPE
near 3000 J/kg will support numerous showers and storms with some
low-end potential for damaging wind gusts. Given the saturated soil
conditions in SW VA and NE TN, the flooding concerns may continue.

The large ridge to our west begins to build eastward on Tuesday.
This will reduce our rain chances and increase our temperatures.
Heat Index values will likely exceed 100 degrees next week, with
105+ possible by midweek in the central and southern TN Valley. The
ridge will likely suppress convective activity, with only slight to
low chances of rain, favoring the higher terrain. By late in the
week, the ridge may begin to loosen its grip on the region, allowing
for increasing rain chances area-wide on Friday and Saturday.

&&

.AVIATION...
(18Z TAFS)
Issued at 156 PM EDT Sat Jul 19 2025

With little change in the weather pattern and air mass over the next
24 hours, the TAFs will follow a persistence forecast. Afternoon and
evening showers/storms will affect the area through the rest of the
afternoon , with the best chance of TSRA at TRI. MVFR to IFR cigs
can be expected again at all sites late tonight and tomorrow
morning, especially if rain occurs at the terminal this
afternoon/evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             73  92  74  95 /  20  50  10  60
Knoxville McGhee Tyson Airport, TN  74  91  74  93 /  30  60  30  60
Oak Ridge, TN                       73  90  73  92 /  30  60  30  70
Tri Cities Airport, TN              71  87  70  86 /  60  70  50  70

&&

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

$$

SHORT TERM...DGS
LONG TERM....DGS
AVIATION...DGS