National Weather Service Raw Text Product

208 
FXUS64 KMRX 251702
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
102 PM EDT Wed Jun 25 2025

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 129 AM EDT Wed Jun 25 2025

Key Messages:

1. Heat Advisory continues today for Heat Index around 105.

2. Isolated strong to severe storms are possible late this afternoon 
and evening. 

Discussion:

A large high pressure ridge remains over the area today, with little 
change in its position from yesterday. Under this ridge, we will 
have another day of hot and humid conditions, with the Heat Index 
reaching near or just over 105 for much of the Tennessee Valley and 
Cumberland Plateau. Temperatures are expected to be pretty similar 
to what we saw yesterday, with highs mainly in the mid to upper 90s. 
Dewpoints yesterday afternoon were mainly in the 68-73 range, and 
that will be close to what we expect today (continued to use a blend 
of NBM and NBM10 for daytime dewpoints). 

CAPE will be plentiful in this air mass, likely between 2500-3000 
J/kg for much of the area. Convection should have no problem 
breaking through a weak cap in the early to mid afternoon, 
especially in the higher terrain and in NE TN/SW VA where the cap is 
weakest (the slightly stronger cap will have greater effect west of 
I-75). Outflow boundaries from this activity will likely initiate 
convection into the Valley through the late afternoon and evening. 
DCAPE values in the 1100-1300 J/kg range and steep low level lapse 
rates will mean storms will be capable of producing damaging wind 
gusts. Very weak flow through the column will result in slow-mobing 
storms and the potential for localized flooding. 

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 129 AM EDT Wed Jun 25 2025

Key Messages:

1. Increasing moisture arriving Thursday brings higher rain chances 
and slightly cooler temperatures through the weekend.

2. A cold front approaches the area Tuesday/Wednesday, with the 
potential for a very wet period if it stalls nearby.

Discussion:

A weak tropical wave that is currently north of the Bahamas will 
make its way westward, and the large ridge will loosen its grip on 
the Southeast. This will bring greater moisture into the TN Valley 
beginning Thursday. This weak low lingers over the Southeast through 
Sunday, until it starts to get picked up by a shortwave trough to 
the north on Monday. Through the weekend, the high CAPE/low shear 
environment will result in numerous afternoon showers and 
thunderstorms each day, driven mainly by orographic lift and outflow 
boundaries. These pulse storms will be capable of producing damaging 
wind gusts and heavy rainfall that causes localized flooding.

On Tuesday and/or Wednesday, a broad mid/upper trough develops over 
the eastern Conus, and a cold front will approach the region. It 
remains to be seen whether this front stalls over the area and 
brings a very wet period next week (bringing the potential for 
flooding), or if it pushes through and brings a drier and cooler air 
mass. 

&&

.AVIATION...
(18Z TAFS)
Issued at 1212 PM EDT Wed Jun 25 2025

Will be isolated to scattered showers and thunderstorms around 
this afternoon/early evening, and will include prob30 thunder 
groups all sites for the period of greatest probability. Fog 
development will be possible late tonight especially if any given
site sees rain later today (which is still unknown at this time),
but for now will go with a VFR forecast all sites outside of the 
prob30 thunder groups.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             74  96  71  93 /  20  40  30  60 
Knoxville McGhee Tyson Airport, TN  73  94  71  91 /  20  50  30  60 
Oak Ridge, TN                       72  93  71  91 /  10  40  30  60 
Tri Cities Airport, TN              69  91  69  88 /  20  50  30  70 

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...Heat Advisory until 7 PM EDT /6 PM CDT/ this evening for 
     Anderson-Bledsoe-Bradley-Campbell-Claiborne-Grainger-
     Hamblen-Hamilton-Hancock-Hawkins-Jefferson-Knox-Loudon-
     Marion-McMinn-Meigs-Morgan-North Sevier-Northwest Blount-
     Northwest Carter-Northwest Cocke-Northwest Greene-Northwest 
     Monroe-Rhea-Roane-Scott TN-Sequatchie-Sullivan-Union-
     Washington TN-West Polk.

VA...Heat Advisory until 7 PM EDT this evening for Lee-Scott VA.

&&

$$

SHORT TERM...DGS
LONG TERM....DGS
AVIATION...