311
FXUS64 KMRX 161311
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
911 AM EDT Mon Jun 16 2025

...New UPDATE...

.UPDATE...
Issued at 908 AM EDT Mon Jun 16 2025

Currently showers moving across the eastern Tennessee Valley this
morning. No lightning has been detected in the storms for the past
few hours, but with some breaks in the cloud coverage and the sun
making it to the surface we should eventually see some lightning
within these storms as they continue throughout much of the day
today. Expect coverage to trend upward as we move into the
afternoon hours, with the primary hazards being brief heavy
downpours which could lead to water over low lying areas.

&&

.SHORT TERM...
(Today and tonight)
Issued at 325 AM EDT Mon Jun 16 2025

Key Messages:

1. Scattered showers and storms are expected again today, especially
during the early to mid afternoon. Gusty winds and isolated flooding
from locally heavy downpours are possible again.

2. Warm and humid conditions are expected with highs in the 80s for
most.

Discussion:

Currently early this morning, a shortwave is centered just west of
the Mississippi River Valley, along with a weak surface low. A
stationary frontal boundary also extends north and east of the
surface low. Throughout the day, these features will slowly shift
eastward, producing another day with showers and storms. Based on
the latest CAMs, today`s activity looks to be focused in the
northern 2/3 of the area. However, there is an earlier timing
expected, more during the early to mid afternoon. With this timing
and some lingering morning showers, instability may be more limited
to below 1,500 J/kg of MLCAPE. Mid-level lapse rates are also shown
to barely exceed 5 C/km. With PWATs remaining around 1.8 inches,
isolated flooding from locally heavy downpours will be a continued
focus. Some places around Greene County and Chattanooga saw locally
heavy rainfall of an inch or more yesterday and could be more
susceptible to flooding. However, most places have received fairly
light totals so far. As in previous nights, activity will likely
diminish through the evening hours with patchy fog possible again by
early Tuesday morning.

&&

.LONG TERM...
(Tuesday through Sunday)
Issued at 325 AM EDT Mon Jun 16 2025

Key Messages:

1. Showers and storms are expected Tuesday through Thursday with
storms possibly being more organized on Tuesday and Thursday. Strong
winds and localized flooding are the main concerns.

2. A significant heat wave will build this weekend and beyond with
high temperatures likely reaching well into the 90s across many
locations.

Tuesday through Thursday

At the start of the period, the shortwave referenced above will be
centered near the Mississippi River Valley with broad southwesterly
flow locally. Additional moisture advection will push PWATs to
around 2 inches, which is above the 90th percentile for this time of
year. MLCAPE will likely reach or exceed 1,500 J/kg Tuesday
afternoon. Additionally, the progression of this shortwave will
increase winds aloft with largely uni-directional deep-layer shear
reaching to 25 kts. The CAMs currently show convection to develop
and move into the area during the late afternoon into the evening
hours. With this environment, convection may be more organized and
may also bring even heavier downpours with a slightly better threat
for strong winds and/or isolated flooding.

Heading into Wednesday, the shortwave will lift off to the north
with another deepening trough noted to the west. Locally, this will
keep the region in a southwesterly flow pattern with abundant
moisture and sufficient instability for continued showers and
storms. Increasing cyclogenesis and frontogenesis will also be noted
to our north and west with a surface low tracking towards the Great
Lakes. By Thursday, this shortwave and frontal boundary will move
over the region, which may bring organized and widespread storms,
possibly in the form of a QLCS. The current afternoon to evening
timing would provide the best instability. There is still
uncertainty at this time, but this will be something to watch in
the coming days.

Friday through Sunday

By Friday, the trough will move off to our east with high pressure,
leading to much drier conditions than in recent days. Then through
the weekend, focus will turn towards what will likely be a
significant heat wave across much of the eastern United States. The
current guidance suggests a 500mb high to reach 5,940m by Saturday,
then possibly exceeding 5,960m by Sunday. There is still uncertainty
as to where it will be centered, but 500mb heights of this magnitude
are near record high values based on climatology. This pattern will
be a shift from what has been seen so far with Knoxville`s lack of
reaching 90 degrees so far being the first time since 2009.

&&

.AVIATION...
(12Z TAFS)
Issued at 650 AM EDT Mon Jun 16 2025

TRI has been persistently MVFR with CHA bouncing around between
VFR and MVFR. It is expected that CHA will stay as VFR in the next
hour or two with TRI likely remaining MVFR until around noon.
There are also showers in the vicinity of TRI with VCTS expected
there and at TYS through the afternoon hours. Reductions to MVFR
or less are possible if any showers or storms move over the
terminals. For CHA, coverage is expected to be less with potential
for storms to move in by early evening. At all of the sites, winds
will be generally from the southwest at around 10 kts. Overnight,
showers and storms will diminish again with potential for MVFR
again by early Tuesday morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             88  70  86  71 /  50  50  90  40
Knoxville McGhee Tyson Airport, TN  86  70  85  71 /  70  50  80  60
Oak Ridge, TN                       85  70  84  70 /  80  60  90  50
Tri Cities Airport, TN              83  67  85  68 /  80  50  70  50

&&

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

$$

SHORT TERM...
LONG TERM....BW
AVIATION...BW