Knoxville, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

182
FXUS64 KMRX 191112
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
712 AM EDT Sat Jul 19 2025

...New AVIATION...

.SHORT TERM...
(Today through Sunday)
Issued at 137 AM EDT Sat Jul 19 2025

Key Messages:

1. Scattered to numerous showers and storms are expected each
afternoon and evening, with the greatest coverage north of I-40.

2. Heavy rain leading to isolated flash flooding will be the primary
concern with storms today through Sunday evening.

Discussion:

A stationary boundary is currently over Kentucky, this boundary will
lift north today as low pressure moves into the Upper Midwest and
Great Lakes. In the upper levels, a nearly zonal pattern is over the
northern half of the U.S. and a ridge is centered over the Southeast
U.S. A shortwave will move through the Ohio Valley this evening,
aiding with development and growth of storms. Deep layer southerly
flow will continue to bring ample moisture into the region with PWat
values around 2 to 2.2 inches today and Sunday. Southwest Virginia
in particular has had repeated heavy rains over the past couple of
weeks. There will likely be a lull in activity through morning but
localized flooding will be a threat again this afternoon/evening
through Sunday evening.

A few strong to severe storms will also be possible this afternoon
with CAPE around 1500 to 2500 J/kg. The primary threat will be gusty
winds. The pattern will be almost the same for Sunday, with weak
troughing over the Ohio Valley and a lingering surface boundary over
the Ohio Valley. Good coverage of showers and storms are expected
again Sunday afternoon and evening so the threat for localized
flooding will continue.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 137 AM EDT Sat Jul 19 2025

Key Messages:

1. Scattered storms will continue through early next week 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.

Discussion:

The wet pattern continues through at least Monday as a lingering
boundary separates high pressure over the Great Lakes and high
pressure near the Gulf Coast. In the upper levels, a ridge will be
building into the Central U.S. By Tuesday or Wednesday, less
coverage in afternoon thunderstorms will be likely as the ridge axis
moves into the Southeast. With the surface high to the east over the
Atlantic, deep layer moisture will be present and diurnal storms can
still be expected but may be more hit and miss. Monday may have a
lingering threat for localized flooding mainly in locations that
already have saturated soils from recent rains. Lower afternoon
storm coverage will likely continue through the end of the week,
especially in the TN Valley.

The heat continues with highs in the 90s for the TN Valley
especially by Tuesday onward. Heat indices will be around 100 to 105
degrees in the Southern and Central TN Valley.

&&

.AVIATION...
(12Z TAFS)
Issued at 709 AM EDT Sat Jul 19 2025

All TAF sites have reported MVFR early this morning. This is
expected to continue off and on for a few hours with additional
MVFR likely at CHA in the next several hours as storms move in
from the southwest. TYS and TRI are also expected to see storms at
least in the vicinity, but the timing will be mid to late
afternoon. Within any storm, reductions to MVFR or less can be
expected. Winds will be generally from the southwest at 10 kts or
less. Coverage of storms is expected to decrease before sunset.
There are additional chances for MVFR tonight, but it was left out
of the TAFs because of limited confidence.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             88  74  93  75 /  80  30  60  10
Knoxville McGhee Tyson Airport, TN  88  74  90  74 /  70  50  70  30
Oak Ridge, TN                       87  72  91  73 /  80  40  70  30
Tri Cities Airport, TN              86  71  85  70 /  80  50  80  50

&&

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

$$

SHORT TERM...McD
LONG TERM....McD
AVIATION...BW