649
FXUS64 KMRX 140552
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
152 AM EDT Tue May 14 2024

...New AVIATION...

.UPDATE...
Issued at 1119 PM EDT Mon May 13 2024

Forecast is on track tonight, with no significant changes made to
the current forecast. Looking ahead to tomorrow, the overall
expectation is the same. Couple rounds of showers and
thunderstorms expected, with the stronger thunderstorms bordering
severe arriving in the late afternoon in a broken set of clusters
of cells. Stronger to severe activity will most likely be south
of Interstate 40.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 215 PM EDT Mon May 13 2024

Key Messages:

1. Wind Advisory for the far east Tennessee Mountains and
Foothills. Gust up to 45 mph possible.

2. Strong to possibly severe storms late Tuesday afternoon and
evening for the Plateau and southeast Tennessee. Marginal severe
hail up to 1 inch and strong gusty winds to 50 mph are possible.
Low-end threat of tornadoes across southeast Tennessee late in the
day.

Discussion:

Through the rest of the afternoon into the evening, weak
isentropic lift will produce scattered showers with light rain or
sprinkles. Besides the potential of light rain, main concern will
be windy conditions across the far east Tennessee Mountains and
Foothills. Camp Creek currently reporting gusts to around 35 mph
but speeds have decreased at Cove Mountains. The low-level jet is
forecast by HREF to increase this evening and expect the greatest
potential of strong winds between 01-06Z.

The boundary layer jet will enhance the potential for scattered
showers this evening/early morning especially over southwest
Virginia and northeast Tennessee.

For Tuesday, upper forcing from the left exit region of the jet
moving into the northern Gulf Coast states and continued
isentropic lift will pull warm/moist air into the region. The
model soundings show more elevated instability as the warm front
remains south of the area until late. Exact timing of a band of
scattered showers and storms remains uncertain but do expect an
area of convection during the day moving northeast.

By late afternoon, another area of convection will form over
middle Tennessee moving the Plateau and southeast Tennessee. This
second area of showers and storms will be more surface based with
MLCAPES up to 1500-1800. Shear will be strong enough to support
organized multi-cluster storms with effective shear of 35 m2/s2.
Mid-level lapse rates are near 6.5 which also supports decent hail
growth resident time. Overall, marginal severe hail and damaging
winds are the main threat.

The HREF is showing some 2-5km updraft helicity tracks across
southeast Tennessee with latest HRRR depicting 0-1km shear of
15-20kts. There is a low-end probability of tornado development
across these areas late in the day.

&&

.LONG TERM...
(Tuesday night through next Monday)
Issued at 215 PM EDT Mon May 13 2024

Key Messages:

1. Showers and thunderstorms continue through Wednesday.

2. A short break is expected, before another round of storms begins
heading into the weekend.

Discussion:

Tuesday evening/night should be the time-frame when we see the
boundary associated with this early week system move thorugh the
area providing a decent environment for thunderstorms. Forecast
soundings show there could be areas of over 500 J/kg of available
CAPE and some moderate (albeit mostly unidirectional) shear in the
mid and deep layers. This atmosphere should be conducive to seeing
more widespread thunderstorms and maybe even some strong to severe
thunderstorms. In the strongest storms we could possibly see near
severe level winds and marginally severe hail... But the primary
threat for the day continues to be the chances for isolated flooding
under heavy thunderstorms. With the weak and nearly unidirectional
shear the threat for tornadoes looks very low at this time. We
should get a break for much of the night and into early Wednesday
morning before the base of the trough/low moves overhead later in
the day leading to another (but hopefully more tame) round of
showers and thunderstorms.

Much of Wednesday night and Thursday should be dry as we sit between
systems and we should see temperatures climb back up to near or
above normal as we head towards the weekend.

By Friday we`ll see increasing precipitation chances as another
system looks to move out of the southern plains towards the
Ohio/Tennessee Valleys through the weekend. There is high confidence
in showers and thunderstorms across the southeast Friday/Saturday,
but lower confidence on the timing and strength of the storms. Some
models are showing more vigorous thunderstorm activity to our south
near the Gulf Coast which typically inhibits convection in the
southern Appalachian. But if the boundary and storms develop further
to the north we`ll likely see more widespread thunderstorms in our
region.

&&

.AVIATION...
(06Z TAFS)
Issued at 143 AM EDT Tue May 14 2024

Expecting a couple rounds of showers and thunderstorms Tuesday,
with the first approaching the area mid-morning and the second and
probably stronger thunderstorms, arriving from the west sometime
in the late afternoon and evening. CHA appears will remain mostly
MVFR for the day with possible IFR before sunrise and with the
first batch of precipitation. TYS and TRI appear will remain VFR
to low VFR with CIGS dropping from a shower or thunderstorm
through the period. Winds no more than 10 KT, but could very well
gust with a thunderstorm.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             76  63  78  61 /  90  70  60   0
Knoxville McGhee Tyson Airport, TN  76  61  74  60 /  80  80  90  20
Oak Ridge, TN                       75  61  74  60 /  90  80  90  20
Tri Cities Airport, TN              76  58  71  59 /  70  80 100  40

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Wind Advisory until 4 AM EDT early this morning for Blount Smoky
     Mountains-Cocke Smoky Mountains-Sevier Smoky Mountains-
     Southeast Carter-Southeast Greene-Southeast Monroe-Unicoi.

VA...NONE.
&&

$$

SHORT TERM...Wellington
AVIATION...KS