Roan Mountain, Tennessee Weather Forecast Discussion

511
FXUS64 KMRX 201748
AFDMRX
Area Forecast Discussion
National Weather Service Morristown TN
148 PM EDT Sat Sep 20 2025
...New DISCUSSION...
.KEY MESSAGES...
Updated at 128 PM EDT Sat Sep 20 2025
-  Above normal temperatures will persist through early next
    week.
-  A few afternoon showers and storms will be around this
    afternoon through Tuesday. Coverage will be more isolated in
    valley locations but could become more scattered across higher
    terrain.
-  Chances for showers and storms will trend upward by the middle
    and latter portions of the work week. Potential of isolated
    severe storms but confidence is low.
&&
.DISCUSSION...
Issued at 128 PM EDT Sat Sep 20 2025
Currently, isolated to scattered showers and storms have
development across the higher terrain but having a hard time
moving into the valley. This is because of fairly strong CIN
across much of the region which will limit development until late
this afternoon/early evening. Best the instability is generally
along and east of interstate 75 with MLCAPES of 1500+. Hail CAPE
of 500-700 with mid-level lapse rates of 6-6.3 degrees. Can not
rule out an isolated strong storm late today with strong/gusty
winds and hail possible.
For tonight, patchy fog possible otherwise mostly clear.
Ensemble cluster analysis and deterministic models show surface
ridging remaining across the southern Appalachians with short-wave
to our west through Tuesday. Persistence will be the forecast with
isolated to scattered storms possible each day, mainly during the
afternoon/early evening, with greatest coverage over the higher
terrain.
A strong upper trough will dig into the mid-section of the nation
for mid-week then into the Tennessee valley for the later half.
Ensemble clusters do show some variance in exact location of this
trough and potential instability. Greater coverage of showers and
storms are likely for the latter half of the week. There is a
potential of isolated severe storms as well but confidence is low
at this time.
&&
.AVIATION...
(18Z TAFS)
Issued at 116 PM EDT Sat Sep 20 2025
Main concerns is the potential of storms at TRI between 20-23Z.
Also, the potential of fog development at TRI especially if rain
occurs later today.
Otherwise, VFR conditions are expected. Weak pressure gradient
over the area will produce light and variable winds outside of
convection.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             66  89  67  88 /  10  20  30  30
Knoxville McGhee Tyson Airport, TN  63  87  64  86 /  10  20  20  30
Oak Ridge, TN                       63  87  64  85 /  10  20  20  40
Tri Cities Airport, TN              60  83  60  82 /  20  10  10  40
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DISCUSSION...DH
AVIATION...DH

NWS MRX Office Area Forecast Discussion