005
FXUS64 KMRX 100235
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
1035 PM EDT Tue Jul 9 2024

...New UPDATE...

.UPDATE...
Issued at 1030 PM EDT Tue Jul 9 2024

The isolated showers and storms that developed across parts of
the forecast area late this afternoon and early evening have ended
with daytime heating. The cold front that is trailing the remnants
of Beryl was over middle Tennessee at this time with a narrow line
of showers and a few thunderstorms. Over the next few hours this
line will move into the plateau counties and then is expected to
weaken and slowly dissipate as it moves into the Tennessee Valley
counties around 6 to 8Z. Expect breezy winds in the mountains
tonight as a tight pressure gradient will be across the higher
elevations. Winds may gust into the 30s in the mountains. Updated
forecast to change rain chances and update temperatures, dewpoints
and sky conditions.

&&

.SHORT TERM...
(This evening through Wednesday)
Issued at 240 PM EDT Tue Jul 9 2024

Key Messages:

1. Scattered to isolated showers/storms through this evening ahead
of an approaching cold front.

2. Breezy conditions in the mountains tonight and Wednesday morning.

2. A cooler and drier air mass will build into the area behind the
front tomorrow.

Discussion:

Through the rest of the afternoon, isolated to scattered showers and
thunderstorms will affect portions of the area. The best coverage
through the afternoon/evening will likely be in the NE TN areas,
where convective development in the mountains will track north
into the Tri-Cities area, and outflow boundaries may initiate
Valley convection.

As the remnants of Beryl track across the lower OH Valley and Great
Lakes region, a trailing cold front will push across TN through
tonight. Models show a line of showers/storms in the Plateau around
03-06Z, but dissipating as it moves into our area. Will have some
chance PoPs west of I-75 for this feature, but dropping quickly to
no PoPs after 08Z.

The pressure gradient overnight and Wednesday morning will create
some breezy conditions in the area, mainly the mountains where gusts
up to 40 mph will be possible. Expect that winds will stay just
under the criteria for a Wind Advisory for most mountain locations,
as the SW direction will not be favorable for mountain wave
enhancement.

Behind this front, low level moisture will still be present, and
will likely result in some broken to overcast low clouds through the
morning hours. Some downslope effect off the Plateau may lead to
gradual scattering/lifting of clouds late in the morning, followed
by mostly clear skies by the afternoon. With deep boundary layer
mixing, dewpoints should drop to a pleasant 60-65 range in most
spots, and with cooler highs in the mid to upper 80s with a 8-12 mph
wind, it will be a welcome change from the recent heat and
humidity.

&&

.LONG TERM...
(Wednesday night through next Tuesday)
Issued at 240 PM EDT Tue Jul 9 2024

Key Messages:

1. Normal humidity through the rest of the week, heat to return
for the weekend. Temperatures early next week to be near record
highs.

2. Low afternoon chance of showers or thunderstorms, likely isolated
to the mountains. Dry weather likely to persist for most.

Discussion:

The long term period will be characterized by a potent upper ridge
anchored over the Rockies out west, which at first allows for better
troughing here in the Eastern US. The upper trough that Beryl`s
remnants will be pivoting through will provide weak northerly to
eventually variable 850 flow across the region. The result is we
don`t see southerly return flow, so no strong low level moisture
advection, and thus surface dewpoints stay reasonable from a July
standpoint. Additionally, precipitable water profiles appear to run
near normal through the extended.

The bad news is though the humidity looks to cooperate, temperatures
will not. Despite the upper ridge pattern being anchored by strong
ridging in the Rockies and strong ridging in the western Atlantic,
upper heights over the Mid South gradually increase on the backside
of the week heading into the weekend. Heading into next week,
modeled 850 temperatures look to approach near record values when
compared against SPC sounding climatology. The NBM reflects this
by painting a swath of upper 90s across the central and southern
valleys, peaking into the end of the period early next week. A
quick check of daily climate stats reveals these values to be a
couple degrees below the records for the date, so quite hot.
Afternoon dewpoints will beginning to increment upward, but with
temperatures so high, a heat advisory will not be too hard to
reach, should these values hold. As of now, there`s no solid
signal for widespread rainfall, outside of a low chance in the
mountains on most afternoons. Dry weather looks to persist for
most locations.

&&

.AVIATION...
(00Z TAFS)
Issued at 730 PM EDT Tue Jul 9 2024

Scattered showers/isolated storms moving NE towards TYS early
this evening. Included VCTS there for 1 hour. A cold front then
moves across the area later tonight, between about 06-10Z, with
winds shifting to a more W/NW direction at 10-12 kt. Behind the
front low level moisture lingers. MVFR cigs expected at CHA and
TYS through Wednesday AM. TRI may also see MVFR cigs for a few
hours Wednesday morning but confidence too low to include in
current TAF. VFR conditions by afternoon all sites. A few gusts up
to 20 kt possible at TRI and TYS Wednesday morning and afternoon
behind cold front.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             72  89  69  93 /  20  10   0   0
Knoxville McGhee Tyson Airport, TN  75  87  67  90 /  20  10   0   0
Oak Ridge, TN                       72  86  66  90 /  20  10   0   0
Tri Cities Airport, TN              73  86  63  88 /  30  10  10  10

&&

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

$$

SHORT TERM...TD
LONG TERM....Wellington
AVIATION...TD