Johnson City, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

208
FXUS64 KMRX 160539
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
139 AM EDT Mon Mar 16 2026

...New DISCUSSION...

.KEY MESSAGES...
Updated at 139 AM EDT Mon Mar 16 2026

-  A line of strong showers and thunderstorms just ahead of a strong
cold front, will sweep through the forecast area before daybreak
Monday.

-  Conditional tornado threat continues through early morning hours
for the southern Cumberland Plateau and southern Tennessee Valley
areas. Elsewhere, damaging winds remain the primary concern.


-  Behind the front, very cold air surges in Monday and continues
across the area through Wednesday morning. Light snow accumulations
appear likely in higher elevations of the East Tennessee mountains
and parts of southwest VA Monday afternoon and night. Light snow
showers could even occur down to the valley floor, but no
accumulations are expected there.

-  Gradual warming trend with mostly dry conditions mid week into
   the weekend.

&&

.DISCUSSION...
Issued at 139 AM EDT Mon Mar 16 2026

Main focus of the forecast discussion is the incoming line of storms
and associated severe weather threat overnight, followed by the
stark temperature change and possibility of snow tomorrow and
tomorrow night.

First off, the severe storm chances. Current regional radar imagery
shows a solid line of thunderstorms stretching along a cold front
from central Indiana, south through Middle Tennessee and into
northern Mississippi as of 10:30 PM EDT this evening. This will
continue to shift east overnight, arriving in the plateau areas by
around 2-3 AM EDT, and pushing east of our CWA by 5-6 AM EDT. In
terms of severe threat, it remains a conditional threat for both
damaging winds and tornadoes. Surface obs and mesoanalysis show LCLs
are higher than you would want to see across Middle Tennessee and
adjacent areas largely due to lower dewpoints (low to mid 50s).
However as the low level jet and surface flow have strengthened, a
narrow corridor of +60F dewpoints have surged northward just ahead
of the cold front and nearby discrete supercells. Further east, ESE
flow across South Carolina and northern Georgia is also bringing in
some upper 50s to low 60s dewpoints to near the southern TN valley.
Models suggest the southern Cumberland plateau and southern
Tennessee valley will see a similar surge of low level moisture, and
subsequently surface based CAPE, just ahead of the line. As such,
there continues to be a conditional threat for some tornadic
activity, along with a threat of significant damaging winds, south
of the I-40 corridor and mainly west of I-75 through 06-08z (or 2-4
AM EDT) as that line moves in. That said, one thing that concerns me
is the overall lack of storm reports upstream to this point. There
just have not been as many as you might expect, which tells me these
storms are having a hard time mixing winds down to the surface. For
now, the amount of shear in place coupled with the possible
instability means the ceiling for this event remains somewhat high
regardless if the threat materializes. Further northeast, think
Knoxville metro area and points further northeast, the threat
remains a little less certain. Access to better low level moisture
and by extension, better instability, will be limited there. The
tornado risk seems much more subdued there, with the primary threat
being damaging winds. But uncertainty is a little higher there.

Behind the front, strong cold air advection will spread into the
forecast area from the west. Calendar day highs may be set before
daybreak tomorrow, with temperatures holding steady or possibly even
falling slightly through the day. The H85 temperatures fall below
zero by midday across the western parts of the CWA, and area wide by
mid afternoon. Aloft, the entrance region to the departing H3 jet
will be lifting north across the CWA during this time, and forecast
sounding show a deep saturation layer extending through the DGZ for
a few hours before moisture becomes more limited in depth. During
this time, snow levels drop below 2,000 ft MSL, with surface
temperatures in the valley dropping into the mid 30s. As such,
expect precipitation in the higher terrain to switch over to snow by
early to mid afternoon, with some decent accumulations possible in
the Smokies and East Tennessee mountains before all is said and
done. Even some minor accumulations in the higher terrain of the
plateau and VA counties appear possible. Furthermore, snow appears
likely even to the lower elevations of the valley, although the
chances for any accumulations at that low of elevation are near
zero.

Monday night temps drop into the 20s at low elevations area wide,
with highs struggling to make it too far into the 40s on Tuesday. In
general, broad upper troughing continues across the eastern CONUS
through the end of the week, but gradually weakens with time.
Temperatures remain near seasonal norms through Wednesday but then
warm back above normal by the weekend as the influence of a strong
desert southwest ridge expands eastward.

&&

.AVIATION...
(06Z TAFS)
Issued at 120 AM EDT Mon Mar 16 2026

Line of strong to severe thunderstorms will impact the terminals
within the first few hours of the TAFs. Low confidence on the
categories, but high confidence no poor flying conditions. Breezy
winds will continue behind the front, switching to more westerly.
Breezy conditions continue through the remainder of the TAFs
behind the front.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             46  27  45  28 /  50   0   0   0
Knoxville McGhee Tyson Airport, TN  48  23  40  24 /  70  10   0   0
Oak Ridge, TN                       47  23  40  24 /  70  10   0   0
Tri Cities Airport, TN              56  21  35  18 / 100  30  10   0

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...Wind Advisory until 8 AM EDT this morning for Cherokee-Clay.

TN...Wind Advisory until 8 AM EDT /7 AM CDT/ this morning for
     Anderson-Bledsoe-Bradley-Campbell-Claiborne-East Polk-
     Grainger-Hamblen-Hamilton-Hancock-Hawkins-Jefferson-Knox-
     Loudon-Marion-McMinn-Meigs-Morgan-North Sevier-Northwest
     Blount-Northwest Carter-Northwest Cocke-Northwest Greene-
     Northwest Monroe-Rhea-Roane-Scott TN-Sequatchie-Sullivan-
     Union-Washington TN-West Polk.

     High Wind Warning until 10 AM EDT this morning for Blount Smoky
     Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky
     Mountains-Southeast Carter-Southeast Greene-Southeast
     Monroe-Unicoi.

     Winter Weather Advisory from 1 PM this afternoon to 2 AM EDT
     Tuesday for Blount Smoky Mountains-Cocke Smoky Mountains-
     Johnson-Sevier Smoky Mountains-Southeast Carter-Southeast
     Greene-Southeast Monroe-Unicoi.

VA...Wind Advisory until 8 AM EDT this morning for Lee-Russell-Scott
     VA-Washington VA-Wise.

     Winter Weather Advisory from 1 PM this afternoon to 2 AM EDT
     Tuesday for Wise.

&&

$$

DISCUSSION...CD
AVIATION...99