Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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305
FXUS64 KMRX 131134
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
634 AM EST Wed Nov 13 2024

...New AVIATION...

.SHORT TERM...
(Today through Tuesday)
Issued at 221 AM EST Wed Nov 13 2024

Key Message:

Rain will move through the area starting tonight and continuing
through much of Thursday.

Discussion:

Currently a quiet overnight period as we sit under mid level
ridging ahead of an incoming system that will affect the region
the next couple of days. A low pressure system is moving through
the plains states on its way towards the Great Lakes Region during
the middle part of the work week. This system will also bring
help sweep through a front in the Ohio/Tennessee Valleys as it
interacts with an enhanced plume of moisture moving out of the
Gulf of Mexico and into the eastern Tennessee Valley.

Expect the precipitation to move onto the Cumberland Plateau this
evening, right near sunset ahead of the front. Depending on the
timing of the the precipitation and how fast the front moves
through, we could see a brief period of isolated thunder during
the hottest part of the late afternoon on/near the Plateau. Still
looks as though the vast majority of people will not see any
thunder, but cannot completely rule out a few rumbles this
afternoon/evening. As the sun sets the precipitation will continue
to spread eastward overnight bringing rainfall to most locations
in the Southern Appalachians. Rain should continue through sunrise
for most places, and eventually come to an end as the front moves
through during the daytime on Thursday. Expect the precipitation
to end over the Appalachian Mountains right around sunset on
Thursday, with most places seeing approximately 12-18 hours worth
of light to moderate rain when everything is said and done. We
could see some wrap around precipitation late Thursday across
northeast TN and southwest VA, but the QPF amounts associated with
this portion of the system are expected to be very light.

QPF amounts continue to tick slightly upward as high resolution
models are getting a hold of the system. Expect storm total
rainfall amounts to be between 0.50" and 1.50" with the highest
amounts likely west of I-75 and lower amounts east of I-75.
Flooding appears unlikely as this rain is expected to fall over
the course of approximately 12-24 hours and we`re still fairly
dry in our region. However, with the possibility of an isolated
thunderstorm this afternoon/evening a brief heavy downpour west of
I-75 leading to flooding of poor drainage areas cannot be
completely ruled out, even though it appears unlikely.

&&

.LONG TERM...
(Thursday Night through Tuesday)
Issued at 221 AM EST Wed Nov 13 2024

Key Messages:

1. Dry weather is expected this weekend through Monday.

2. The next system approaches midweek as a deep trough moves into
the Eastern U.S.

Discussion:

In the upper levels, a ridge will slowly build in by Friday evening.
This ridge will hold through the weekend. Mid next week, a deep
trough will move into the Eastern U.S. At the surface, high pressure
will be in place through Monday. A frontal passage will be possible
mid next week.

Saturday, Sunday and Monday will be dry with a warming trend as
ridging and high pressure dominate the region. Temps will be
slightly above normal with highs in the 60s. By next Tuesday or
Wednesday, a cold front followed by a deep trough will be possible.
Rain ahead of the cold front is likely Tuesday and/or Wednesday. The
deep trough may bring some snow to the higher elevations late next
week but it is still very far out.

&&

.AVIATION...
(12Z TAFS)
Issued at 632 AM EST Wed Nov 13 2024

Main weather story will be the incoming rain later this
afternoon/evening. Expect widespread rain to drop
ceilings/visibilities into the MVFR/IFR categories for much of the
overnight hours. Ceilings and visibilities should rebound just
beyond this TAF cycle. Cannot completely rule out a rogue
lightning strike this afternoon at KCHA right as the rain begins,
but chances are too low to mention in the TAFs.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             66  50  61  49 /  40  90  60   0
Knoxville McGhee Tyson Airport, TN  69  49  61  47 /  10 100  90  10
Oak Ridge, TN                       68  48  59  47 /  20 100  90  10
Tri Cities Airport, TN              63  44  56  46 /   0  90 100  50

&&

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

$$

SHORT TERM...
LONG TERM....McD
AVIATION...