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

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FXUS64 KMRX 261525
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
1125 AM EDT Tue Mar 26 2024

...New UPDATE...

.UPDATE...
Issued at 1120 AM EDT Tue Mar 26 2024

Rain with a few embedded thunderstorms are moving northeast
across east Tennessee and adjacent states late this morning.
Strong southeast flow is still occurring across the eastern
mountains along and ahead of the rain bands. The pressure gradient
is also tighter there too. Rainfall amounts have been lighter in
the northeast with the downsloping and that will continue another
few hours. To the west winds have decreased with the pressure
gradient relaxing some. Rainfall amounts overall have not been
real heavy. Have cancelled the wind advisory there but kept the
high wind warning in effect over the higher eastern mountains.
Temperatures are quite uniform at this hour in the mid to upper
50s and should not rise much with the clouds and continued
rainfall. For the rest of the day expect the rain showers to
continue with isolated thunder at times as front slowly moves east
across Tennessee. Winds should decrease by around 18Z in the east
but rain will continue through the afternoon and into the evening
as the front will not reach east Tennessee until between 00z and
06Z tonight. Updated hourly temperature and dew point grids with
updated forecast.

&&

.SHORT TERM...
(Today and tonight)
Issued at 355 AM EDT Tue Mar 26 2024

Key Messages:

1. High winds in the mountains and breezy conditions in
southern/western portions of the area will continue until early
afternoon.

2. Rain will also move in from the west and continue through much of
the day before diminishing by the evening hours.

Today

Currently early this morning, a deep trough and strong upper jet is
located across the central U.S. with a near 990mb surface low
progressing towards the Great Lakes. The associated frontal boundary
is also in West Tennessee. Per model guidance and sounding analysis,
the 850mb jet associated with this system is in excess of 60 kts.
When combined with the strong MSLP gradient, high winds have
continued across the mountains and foothills with confirmed gusts in
excess of 80 mph at Camp Creek and Cove Mountain. Places further to
the south and west have remained very breezy as well with a lesser
degree further north due to terrain orientation. As the frontal
boundary approaches from the west, rain to our west will overspread
the area through the morning hours with isolated thunder chances due
to low-end elevated instability. By early afternoon, the MSLP
gradient and low-level jet will diminish significantly with the
current expiration time and magnitude of the wind products still
decently on track. It is possible that the mountains may hold onto
high winds slightly later than 18Z, but this drop off is
indicated to be fairly quick. Also, with the continued
downsloping, the coverage and intensity of showers will drop off
significantly as it progresses further east. However, even places
further west that see heavier totals will be fairly unimpactful,
especially with limited recent rainfall. By the evening, the front
will be into Middle Tennessee with the better moisture and PoPs
focused in the east.

Tonight

Overnight through the early morning hours, the frontal boundary will
move into the area with the moisture having shifted off to the east.
Some additional light showers could develop near the front, but the
coverage and intensity would be very limited. As the front moves
into the area, places in far western portions of the area will see a
shift to a more westerly to northwesterly wind direction and initial
CAA. Otherwise, temperatures will be fairly mild across most of the
area.

&&

.LONG TERM...
(Wednesday through Monday)
Issued at 355 AM EDT Tue Mar 26 2024

Key Messages:

1. Rain begins to move east of the area on Wednesday. Drier air will
result in low RH values Thursday and Friday.

2. Temperatures drop into the 30s area wide Thursday night/Friday
morning with frost/freeze conditions possible.

3. Shortwave trough may bring a system through the region early next
week with the potential for showers and thunderstorms.

Discussion:

A few lingering showers will be possible early Wednesday morning as
a cold front shifts eastward into the Carolinas. Cooler, drier air
in the low-levels will be advecting into the region with low-level
NW flow. With an inversion aloft, some low-level cloud cover will
continue into the afternoon with more bkn/sct cloud cover and
clearing by late in the day on Wednesday.

By Thursday and Friday, ridging begins to build into the region with
subsidence in the mid and low levels. This drier air and warming
temperatures, especially by Friday, will result in low RH values
across the area.

Late in the weekend, return southerly flow develops with increasing
moisture as surface high pressure shifts eastward. Isentropic lift
will result in some increasing clouds, and perhaps some light rain
showers, mainly north of our area. There is significant spread
amongst model guidance next Monday and Tuesday. However, the general
pattern that is shown by deterministic and ensemble guidance
indicates ridging across the Southeast CONUS with longwave troughing
across the Great Plains through the upper Mississippi Valley. This
will bring a potential of showers and thunderstorms ahead of a cold
front by next Tuesday, but timing is uncertain. CIPS analogs are
hinting at the low potential of severe thunderstorms across the
Tennessee Valley with the system early next week; based on the time
of year and the ensemble guidance, it will be a system to monitor as
it develops over the coming week.

&&

.AVIATION...
(12Z TAFS)
Issued at 714 AM EDT Tue Mar 26 2024

Low-level wind shear will continue over the next few hours at TYS
and TRI before gradually diminishing. Also, rain will continue to
spread throughout the area through the afternoon with a steady
decrease to MVFR conditions. Winds at the surface will be
generally from the south to southeast. These conditions are
expected to improve to VFR from west to east with TRI possibly
holding on to these conditions into the overnight period. Patchy
fog development is possible as well, but confidence is fairly
limited. Winds will also decrease overnight as well.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             61  48  68  45 / 100   0   0   0
Knoxville McGhee Tyson Airport, TN  61  49  67  43 / 100  20  10  10
Oak Ridge, TN                       59  47  68  43 / 100  10  10  10
Tri Cities Airport, TN              57  47  67  42 /  90  50  20  30

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...High Wind Warning until 2 PM EDT this afternoon for Blount Smoky
     Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky
     Mountains-Southeast Carter-Southeast Greene-Southeast
     Monroe-Unicoi.

VA...NONE.
&&

$$

SHORT TERM...TD
LONG TERM....JB
AVIATION...BW


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