Johnson City, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

145
FXUS64 KMRX 192332 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
732 PM EDT Fri Jun 19 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 730 PM EDT Fri Jun 19 2026

- After some morning fog, dry and sunny weather continues Saturday,
with a chance of showers returning Sunday afternoon.

- Showers and storms are likely Monday in multiple rounds. Organized
severe storms are possible, mainly Monday evening.

- Rain chances decrease but continue for the rest of the period
  with temperatures near or below normal.

&&

.DISCUSSION...
Issued at 224 PM EDT Fri Jun 19 2026

High pressure will continue to build across the region from the NW
through the afternoon and evening hours. With the surface high
directly over the area tonight providing clear/calm conditions, some
patchy fog will be possible in some areas, mainly near lakes and
rivers.

A split flow pattern takes a shortwave trough across MS/AL/GA
tomorrow, with a broad trough passing across the Great Lakes and NE
states, leaving our area between systems. This should result in a
dry day with near to slightly below normal temperatures. On Sunday,
a low pressure system crossing the northern Plains will bring a
deeper southerly flow that will warm temperatures into the mid/upper
80s. With the southerly flow will come greater moisture advection
to southern portions of the area. The NBM is quite aggressive
with PoPs in the afternoon, which seems overdone given the
presence of a stable layer between 850-700 mb, with dry air aloft
and little synoptic forcing to provide lift. NBM PoPs on Sunday
will be cut back for this reason.

An upstream MCS in the Mid MS Valley region is expected to be
approaching our area Monday morning. The remnants of this system are
expected to be dissipating as they move east, but it may bring a
round of showers to the area in the morning. The greater potential
for showers/storms comes later in the day and in the evening as
better mid/upper level forcing arrives with the approaching
shortwave trough. The question is if the morning round of showers
will suppress instability and thus the severe storm potential. Given
the 850 mb winds of 30-40 kt, there appears to be adequate shear to
support organized convection, and there could be enough time for air
mass destabilization in the afternoon for MLCAPE to exceed 1500
J/kg. NBM joint probabilities of SBCAPE > 1000 J/kg and bulk shear
> 30 kt is around 50% in the evening. So this will be a period to
watch for possible strong to severe storms. A mention of this
will be added to the HWO.

Next week will feature a broad trough across the eastern Conus,
which will result in low to slight chance PoPs for most days, with
temperatures near to slightly below normal.

&&

.AVIATION...
(00Z TAFS)
Issued at 730 PM EDT Fri Jun 19 2026

Have VFR conditions with light and variable winds through the
period at all sites. Given rainfall yesterday and the combination
of clear skies and light winds overnight, I`m confident that some
patchy fog will develop. I am, however, not confident in how
widespread it will be or whether it would affect any terminals.
So, I left it out with the 00z issuance.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             65  87  68  87 /   0   0   0  30
Knoxville McGhee Tyson Airport, TN  61  86  65  89 /   0   0  10  20
Oak Ridge, TN                       60  86  64  88 /   0   0  10  20
Tri Cities Airport, TN              56  83  60  88 /   0   0   0  10

&&

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

$$

DISCUSSION...DGS
AVIATION...CD