Johnson City, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

146
FXUS64 KMRX 150536
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
136 AM EDT Wed Oct 15 2025

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Updated at 135 AM EDT Wed Oct 15 2025

- Dry weather and seasonal temperatures will continue for the rest
  of the week with Thursday night being cooler than what has been
  seen the past several nights.

- A system will approach the area Saturday night into Sunday with
  widespread showers and a few storms possible. Strong winds are
  also possible in the mountains.

- Cooler and drier conditions return early next week

&&

.DISCUSSION...
Issued at 135 AM EDT Wed Oct 15 2025

Currently early this morning, ridging is to our west with high
pressure in place across the eastern U.S. This same general setup
will continue the pattern we`ve seen in recent days with dry weather
and overall seasonal temperatures. Patchy morning fog is likely in
some spots again to start the day, but mostly clear conditions and a
persistent northerly to northeasterly wind will remain. By Thursday,
ridging will shift to be centered almost directly over the region
with surface high pressure moving just to our northeast. This
location of the surface high will provide better subsidence and
radiational cooling conditions Thursday night, especially in the
northeast. Current indications suggest some places to drop into the
30s with patchy frost certainly possible.

During the day on Friday, focus will turn towards deepening
troughing to our northwest, also accompanied by increasing
frontogenesis. The result on Friday (and especially Saturday) will
be increasing southerly flow and WAA. As this trough moves east,
most sources continue to indicate an increasing negative tilt with
an upper jet over 100 kts north of the Ohio River Valley.
Ageostrophic vertical wind circulations in the right-entrance region
of the jet to our northwest will likely increase nearby 850mb winds
to 40 or 50 kts. Robust convection is anticipated to our west ahead
of this front on Saturday with continued threat for severe weather
in that area. For our area, the currently indicated loss of diurnal
instability will limit severe potential of anything that may arrive
Saturday night. However, the strong 850mb jet may be sufficient for
the first mountain wave high wind event of the season. The MSLP
gradient in our area remains uncertain, in addition to the strength
and exact direction of the 850mb jet. In any case, widespread
showers and a few storms will be supported, likely late Saturday
night to Sunday ahead of the front.

Behind the front, cooler and drier conditions will return Sunday
night into early next week. Latest model guidance differs on the
extent of CAA in our area during this time. Some solutions show
combinations of CAA and subsidence that would be enough for
overnight frost by Monday night.

&&

.AVIATION...
(06Z TAFS)
Issued at 135 AM EDT Wed Oct 15 2025

Fog is likely again at TRI by the early morning hours with
reductions to LIFR anticipated. Fog is not currently anticipated at
CHA or TYS. Otherwise, all sites will remain VFR throughout the day
with mostly clear conditions and northerly to northeasterly winds
of around 10 kts.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             81  58  79  53 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  78  53  75  49 /   0   0   0   0
Oak Ridge, TN                       78  53  75  48 /   0   0   0   0
Tri Cities Airport, TN              74  45  70  40 /   0   0   0   0

&&

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

$$

DISCUSSION...BW
AVIATION...BW