Johnson City, Tennessee 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

404
FXUS64 KMRX 242343
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
743 PM EDT Fri Jul 24 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 729 PM EDT Fri Jul 24 2026

- Isolated to scattered showers and storms possible at times today
  through the weekend. Best chances for rain during this period
  is along the Plateau, central & southern valley, and into the E
  TN mountains & SW NC. Relatively lower chances exist in NE TN
  and SW VA.

- By Sunday, temperatures will rise well into the 80s and low 90s.
  Hot and humid conditions alongside additional isolated to
  scattered storms at times for early next week.

&&

.DISCUSSION...
Issued at 236 PM EDT Fri Jul 24 2026

Generally speaking, the synoptic pattern consist of broad ridging
across much of the CONUS with a weaker trough over the northeast. A
stationary boundary remains situated along our southern CWA border,
and will be the focus for some scattered showers and perhaps a few
rumbles of thunder this afternoon. Due to the morning overcast
conditions CAPE is more limited today, thus, strong convection
threat is very low. Isolated flooding cannot be ruled out where
poor antecedent conditions exist, but with the primary axis of
convergence to our south and improved storm motion, the flooding
threat is also much lower than previous days.

Shortwave energy will dive into the Great Lakes region tomorrow,
with increasing chances for precipitation as a weak vort max rounds
the base of the aforementioned trough, which will then be digging
into the southern Apps. CAPE looks to be very limited so this will
be predominately showers. Still some disagreement with CAMs on how
exactly timing/coverage plays out, but trends lean towards a period
of increased PoP chances Saturday morning into the afternoon. A
brief lull will then be possible, with some additional PoP
chances returning Sat night.

The trough axis looks to begin a slow eastward shift Sunday, with
increasing H5 heights promoting a slight warming trend. Isolated
convection cannot be ruled out in vicinity of higher terrain and
southern valley Sunday afternoon, but most will remain dry for the
bulk of the afternoon and evening. A drier vertical column with high
DCAPE near 1000 J/kg and mid-level lapse rates between 6.5-7degC
could lead to gusty winds if storms can initiate.

Additional periods of showers and storms will be possible into early
next week as bouts of energy round the base of the trough. Highest
PoP chances will be in north and eastern areas. With enhanced shear
due to marginal mid and upper level flow, periods of strong to
severe storm chances cannot be ruled out depending on timing and
availability of instability. Additionally, Monday and Tuesday look
to be the warmest days with heat indices in the mid 90s to low 100s.
A slight moderation in temperatures is expected late week.

&&

.AVIATION...
(00Z TAFS)
Issued at 729 PM EDT Fri Jul 24 2026

Light showers continue near TYS and CHA, possibly for a few more
hours. Isolated to scattered showers are likely tomorrow but will
be hit and miss, chances on station will generally be low
throughout the day. Thunder chances will also be low throughout
the day. MVFR CIGs are likely in the late night and morning hours
at TRI. Some fog will also be possible mainly near TRI.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             71  86  72  90 /  10  40  40  20
Knoxville McGhee Tyson Airport, TN  69  85  70  88 /  20  20  40  10
Oak Ridge, TN                       68  85  69  88 /  10  20  20  10
Tri Cities Airport, TN              66  81  64  84 /  50  10   0  20

&&

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

$$

DISCUSSION...KRS
AVIATION...McD