425
FXUS64 KMRX 080013 AAB
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
813 PM EDT Sat Jun 7 2025

...New AVIATION...

.SHORT TERM...
(This evening through Sunday night)
Issued at 230 PM EDT Sat Jun 7 2025

Key Messages:

1. An approahcing MCS will track across the area this evening, with
damaging winds and flooding being the primary hazards, mainly south
of I-40.

2. Scattered showers/storms continue into Sunday morning, exiting to
the east through the day.

Discussion:

A moist and unstable air mass is in place across East TN this
afternoon, especially south of I-40 where morning heating has
allowed temperatures to rise into the mid 80s. This, along with
increasing deep layer shear, will help maintain the approaching MCS
as it reaches our area. The threat for damaging winds will exist for
the Plateau and southern and central TN Valley between 4 pm and 8 pm
EDT. Wind gusts of 70-80 mph will be possible. A low-end hail threat
will be present as well, and an isolated tornado cannot be ruled out
near the GA border, where the HRRR shows some UH tracks. Expect that
a SVR Watch will be issued soon. A flooding threat will also exist
due to high rainfall rates and moist ground conditions from
yesterday`s rainfall.

As the MCS tracks east, the northern portions of it to the north of
I-40 will encounter a less favorable air mass north of a boundary
where cloud cover has been greater, and it should lose its strength.
Additional showers/storms will likely continue overnight as we will
have a jet streak and shortwave trough that will move through the
region through Sunday morning. The lack of instability will keep the
threat of strong to severe storms low this period. There will also
be some midlevel drying, and PW values will be falling overnight to
near 1 inch by Sunday afternoon, so the flooding threat should be
diminishing tonight, although training cells are possible given the
unidirectional winds through the column. Coverage should mainly be
scattered Sunday morning, falling to isolated to nothing in the
afternoon.

&&

.LONG TERM...
(Monday through next Saturday)
Issued at 230 PM EDT Sat Jun 7 2025

Key Messages:

1. An approaching surface front will continue the chance for showers
and storms Monday afternoon through Monday night. Chances for severe
weather are marginal at this point, with isolated flooding possible
due to the repeated rounds of activity over multiple days.

2. Conditions trend drier and gradually warm Tuesday through
Wednesday.

Discussion:

An upper trough axis swings into the the Great Lakes and Ohio Valley
region to kick off the new work week. Bouts of vort lobes rounding
the base of the trough, diurnal heating, and an approaching surface
front will continue the chance for showers and a few thunderstorms
Monday. Latest guidance trends, including the NAM, suggest the
frontal passage may occur more so Monday evening into the overnight
hours. The NAM is often times bullish with instability and latest
model derived soundings struggle to reach 750 J/kg of mixed layer
CAPE among marginal bulk shear of 25-30kts. Thoughts remain that
strong to severe chances are more marginal at best but we will
continue to monitor trends.

This has NBM PoPs trending lower for Tuesday afternoon as high
pressure builds in from the northwest and the upper trough lifts
northeast. We will finally be seeing a drying trend from Tuesday
afternoon through Thursday afternoon, though some areas may see
light activity lingering briefly Tuesday. Increasing upper level
heights will promote a warming trend through this period as well. By
Thursday, most locations throughout the East Tennessee Valley will
be approaching the upper 80s. Roughly 5 degrees above normal for
early to mid June. Shower and thunderstorm chances return late week
into the weekend as surface high pressure drifts eastward over the
Atlantic.

&&

.AVIATION...
(00Z TAFS)
Issued at 757 PM EDT Sat Jun 7 2025

Remnant SHRA will push through KTRI here in the next few hours.
Expect additional SHRA to move into east TN after 08z or so.
Guidance suggests they`ll be scattered across the region so do
have PROB30 at each site to account for this. Otherwise, due to
incoming showers later tonight, there`s a lot of uncertainty with
regards to flight categories. They should remain largely VFR
except at KTRI, but would not be surprised of fog and/or low
clouds develop due to rainfall today.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             88  70  86  66 /  90  60  40  10
Knoxville McGhee Tyson Airport, TN  85  69  83  64 /  80  80  40  10
Oak Ridge, TN                       85  67  83  63 /  90  80  30  10
Tri Cities Airport, TN              81  66  80  61 /  70  80  50  10

&&

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

$$

SHORT TERM...DGS
LONG TERM....KRS
AVIATION...CD