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247
FXUS64 KMRX 080130
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
930 PM EDT Fri Jun 7 2024

...New UPDATE...

.UPDATE...
-- Changed Discussion --
Issued at 926 PM EDT Fri Jun 7 2024

The forecast generally looks to be on track on this rather
tranquil weather evening. Will just make a few minor tweaks
mainly to hourly temps and dew points with this update.
-- End Changed Discussion --

&&

.SHORT TERM...
(This evening through Saturday)
Issued at 316 PM EDT Fri Jun 7 2024

Key Messages:

1. Dry and clear tonight.

2. Outside chance of some light showers moving into the northern
plateau and Virginia counties during the afternoon hours.

Discussion:

Pretty tranquil weather is in store for the short term period. Broad
upper ridging, anchored over the Arklatex region, will remain in
place across the deep south through the period while a potent upper
low shifts east from the Great Lakes region. Surface high pressure
will slide eastward along the I-40 corridor across Tennessee late
tonight and into tomorrow. We remain in a dry, post-frontal air mass
this afternoon and tonight, with dewpoints falling this afternoon
and RHs unexpectedly falling into the 25-30 percent range for many
areas. That will recover some tonight as we have good radiational
conditions with clear skies and light winds. Don`t think it will be
enough for fog development though and do not have any in the
forecast.

For tomorrow, most all guidance shows and MCS forming over the
central plains tonight and riding the periphery of the ridge
eastwards into Kentucky late tonight into tomorrow. Most guidance
washes this out as it moves into eastern Kentucky, which makes since
given the dry air mass in place currently. Worth noting however that
there are enough guidance sources that do bring it into our northern
plateau and Virginia counties late in the afternoon hours. Left the
NBM PoP guidance in place as it advertises from bare minimum slight
chance PoPs and it seems reasonable. Regardless, model soundings
suggest any rain would fall out of a mid level deck associated with
the decaying MCS, so no thunder would be expected, and the rain
would be very light.

&&

.LONG TERM...
(Saturday night through next Friday)
Issued at 316 PM EDT Fri Jun 7 2024

Key Messages:

1. Showers and thunderstorms return Sunday accompanied by a cold
front.

2. Uncertainty grows from Monday onward with isolated to scattered
showers and thunderstorms forecast each day; a more typical summer
pattern.

Discussion:

To start the period, high pressure this weekend will exit to the
east as a system riding atop the upper high over the Gulf rolls
eastward bringing our area its next chance for showers and
thunderstorms. Currently out of the whole period, showers and storms
Sunday will be more numerous to widespread. Marginal severe is
possible, as CAPE values will be a few hundred to around 1000 J/kg,
with sufficient deep layer shear, and the return of moisture. SPC
only has the area under general thunderstorms, but will continue to
monitor to see if this changes as it is on Day 3. After the
aforementioned cold frontal passage, we lose the humidity again and
temperatures will run a couple of degrees below normal until a warm-
up returns mid to late week.

Past Sunday, uncertainty grows when each day could feature isolated
to scattered thunderstorms; a more diurnal set-up. Troughing over
the east may support development through at least Tuesday until
ridging begins to build in. Late Tuesday through the end of the
week, weak flow aloft will develop. A shortwave trough over the
Midwest is forecast to cut-off and move over the Gulf around
Thursday, which may be the source of moisture the end of the week.
Otherwise, high pressure expected to dominate at the surface much of
the period after Sunday, with increased chances of your typical run
of the mill summer showers and thunderstorms in the afternoon and
early evening each day. Temperatures will begin to trend above
normal towards the end of the week.

&&

.AVIATION...
(00Z TAFS)
Issued at 637 PM EDT Fri Jun 7 2024

VFR conditions expected for the period all sites. Winds will
generally be light.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             61  87  68  89 /   0  10  10  40
Knoxville McGhee Tyson Airport, TN  58  83  66  82 /   0  10  30  70
Oak Ridge, TN                       57  82  66  81 /   0  10  30  70
Tri Cities Airport, TN              53  79  63  77 /   0  10  30  70

&&

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

$$

SHORT TERM...
LONG TERM....KS
AVIATION...