247
FXUS64 KMRX 151721
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
121 PM EDT Tue Jul 15 2025

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 1243 AM EDT Tue Jul 15 2025

Key Messages:

1. Scattered storms are expected this afternoon into the evening
with localized flooding and a few stronger storms possible.

2. Hot and humid conditions will continue with highs rising into the
90s for most places.

Discussion:

Currently early this morning, weak flow is in place aloft with 500mb
ridging of over 5,910m centered over the eastern U.S. Bermuda High
pressure is also in place over the Atlantic. This will provide a
continuation of the typical summer pattern with hot and humid
conditions and diurnal convection expected again. The better
moisture is expected to remain to our northwest and to our south and
east with a weak tropical system likely to develop east of Florida
and track westward. The convective environment will comparable to
yesterday with virtually 0 shear and MLCAPE in excess of 1,500 J/kg.
While they differ, the CAMs collectively show better coverage of
convection than yesterday with the most likely timing to be 3 PM
until 9 or 10 PM. As in recent days, localized flooding and a few
strong storms remain possible. Activity will diminish overnight with
mild temperatures and patchy fog for places that see rainfall.

&&

.LONG TERM...
(Wednesday through Monday)
Issued at 1243 AM EDT Tue Jul 15 2025

Key Messages:

1. Daily storms are expected through the period with better coverage
possible than early in the week.

2. Hot and humid conditions will persist with highs in the 90s and
heat index values around 100 degrees for many places.

Wednesday through Friday

At the start of the period, strong ridging will be in place with
Bermuda High pressure prevailing to our east. The weak tropical
system referenced in the short term period is expected to be
tracking along the northern Gulf. This will continue the summer
pattern with weak flow aloft and similar thermodynamics as in the
short term period. Hot and humid conditions and diurnal convection
can be expected. A frontal boundary will also come into view over
the northern Plains on Wednesday with southward progression into
Thursday. The aforementioned tropical disturbance is also expected
to move over Louisiana before gradually dissipating as it progresses
northward. This will provide better moisture in our area for the end
of the week, compared to recent days. The front is likely to weaken
as it settles near the Ohio River Valley, which, combined with
increased moisture, will make the case for better convective
coverage. As in recent days, localized flooding and isolated strong
storms will remain possible.

Saturday through Monday

Heading into the weekend, a similar pattern will remain in place
with 500mb heights reaching or exceeding 5,940m across much of the
eastern U.S. Hot and humid conditions will prevail with abundant
moisture keeping daily chances for showers and storms. The threat
for localized flooding and isolated strong storms will remain each
day. The overall flooding threat will be specific to which places
see repeated convection, but efficient rainfall rates will be
realized, given the environment.

&&

.AVIATION...
(18Z TAFS)
Issued at 117 PM EDT Tue Jul 15 2025

Afternoon and evening convection is possible at each TAF site.
TRI/TYS have the greatest chance of storms as the upper ridge is
strongest across the southern valley. Another concern is the
potential of fog/low-cloud development. Since TRI has the greatest
potential of storms included the potential of low-clouds there.

Otherwise VFR conditions.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             75  95  75  94 /  20  50  30  60
Knoxville McGhee Tyson Airport, TN  73  93  74  93 /  30  50  40  60
Oak Ridge, TN                       72  93  74  92 /  20  50  30  60
Tri Cities Airport, TN              69  90  70  89 /  50  60  40  70

&&

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

$$

SHORT TERM...DH
LONG TERM....DH
AVIATION...DH