-- Discussion containing changed information from previous version are highlighted. --
793
FXUS64 KMRX 181900
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
300 PM EDT Tue Jun 18 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
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(This evening through Wednesday)
Issued at 258 PM EDT Tue Jun 18 2024

Key Message:

1. Hot and dry conditions prevail.

Upper level high centered near Virginia/West Virginia/southeastern
Pennsylvania will gradually drift northwest over the next 24 hours.
There has been some scattered thunderstorm activity develop along
the western edge of the ridge this afternoon. Expect that the
majority of activity will generally stay north and west of the
forecast area through the remainder of the afternoon. There may be a
few isolated showers that do develop in our forecast area but they
should be short lived.

The surface high will build west and provide a more stable
atmosphere overnight and into Wednesday. As such, no convective
activity is expected. Sadly, hot temperatures will persist and will
only be a degree or two cooler.
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&&

.LONG TERM...
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(Wednesday night through next Tuesday)
Issued at 258 PM EDT Tue Jun 18 2024

Key Messages:

1. Above average temperatures continue Thursday through the
extended.

2. Diurnal convection possible this as early as Saturday afternoon
but higher chances Sunday and early next week as a frontal boundary
approaches the area late Sunday into Monday.

Discussion:

Strong ridging will continue across the Eastern states through the
weekend with 594 to 598 dam 500mb heights across the Appalachians
through Saturday. A continued subsidence pattern under the ridge
will keep the threat for showers and storms away. The easterly to
northeasterly flow will continue with downslope conditions and
dewpoints will be lower in the lower to mid 60s. Instability will be
limited and temperatures will be up in the lower to mid 90s.

On Saturday a shortwave trough across the upper Mississippi Valley
will slowly move southeast toward the Ohio Valley. There should be
an increase in moisture from the south as the surface high shifts a
little further east. A few terrain showers and storms are expected
to form in the eastern TN mountains and possibly southwest Virginia.

Sunday the front is expected to get a little closer with a better
chance of afternoon and evening showers and storms as the upper
ridge flattens out. A weak surface cold front will also approach the
area Sunday night and Monday. Increasing southerly boundary layer
flow and increasing low-level moisture and decreasing upper-level
heights will also raise instability. There should be an increase in
the chance of diurnal showers and thunderstorms Monday across the
region.

Models then want to keep the front over the forecast area Tuesday.
Highest chances Tuesday look to be over the southern part of the
area based on where the cold front ends up. This will likely change
with the slow movement of the front.
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&&

.AVIATION...
(18Z TAFS)
Issued at 100 PM EDT Tue Jun 18 2024

Light easterly winds and VFR conditions will persist for the next
24 hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN             71  91  69  93 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  67  91  67  91 /   0   0   0   0
Oak Ridge, TN                       68  90  67  91 /   0   0   0   0
Tri Cities Airport, TN              64  89  63  90 /   0   0   0   0
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&&

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

$$