438
FXUS64 KMRX 081801
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
201 PM EDT Tue Jul 8 2025

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

.SHORT TERM AND LONG TERM...
(This evening through next Tuesday)
Issued at 1251 PM EDT Tue Jul 8 2025

Key Messages:

1. Increased chances of unsettled weather returns, with PM showers
and storms across the area through next week.

2. Temperatures will trend a bit cooler or around seasonal norms,
into the weekend.

Discussion:

Within the past hour or two, storms have started to initiate over
parts of the Southern Appalachians and southern plateau. Expect a
trend upward in activity for the mountains and plateau the rest
of this afternoon and evening. SBCAPE is around 2000-2500+ J/kg
with PWATs above 1.5". DCAPE is less than it has been the past
couple of afternoons, with better numbers east of Appalachians.
Still, wind gusts with any storm could top 30-40 mph. The primary
threat with any storm today will be heavy rains that may lead to
flooding. A low to isolated chance that the valley sees a storm
the rest of today.

Tomorrow and onward will see an increase in activity for the
entire forecast area. The latest SPC Day 2 Outlook places us under
a MRGL risk for severe storms. Water-loaded downburst winds will
be the primary threat, secondary being a flash flooding
potential. A mid-level trough is expected to traverse the Great
Lakes and Ohio Valley tomorrow. Better shear parameters will be
closer to the Virginias and into the northeast. Even so, numerous
showers and thunderstorms can be expected tomorrow with the
potential for strong to low-end severe.

For the days ahead, ridging will be suppressed to the south with
troughing locked to the north. Waves within the flow, paired with
differential heating, will support PM showers and thunderstorms
pretty much through the entire forecast period. Generally,
scattered to widespread showers and thunderstorms will be
possible. Beyond tomorrow, it isn`t quite known yet if severe
outlooks will need addressed, however, the WPC ERO through
Saturday does highlight either all of the forecast area or parts
of it for at least a MRGL risk for flash flooding, so that
particular threat can be a guarantee within the realm of
possibility.

With slightly lower upper level heights and increased cloud cover
during peak heating the next few days, temperatures will trend
closer to normal with highs mostly in the upper 80s. Early next
week appears to be an upward trend in temperatures again, as
ridging aloft tries to push north, as well as the development of
surface high pressure.

&&

.AVIATION...
(18Z TAFS)
Issued at 1251 PM EDT Tue Jul 8 2025

Best chance for thunderstorms at the 18z issuance time will be
CHA, where storms have already formed nearby and are moving
northeast. Do not have VCTS at TYS or TRI due to low confidence
based on the isolated to scattered regime expected today, mainly
over the higher terrain. Things calm down overnight, before a
pattern of more widespread activity returns to the area tomorrow.
PROB30 added the last couple of hours to show this chance.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             73  92  73  88 /  20  80  40  90
Knoxville McGhee Tyson Airport, TN  72  91  71  88 /  30  80  50  80
Oak Ridge, TN                       71  90  71  87 /  30  80  50  80
Tri Cities Airport, TN              69  88  68  84 /  30  80  70  80

&&

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

$$

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