FXUS64 KMRX 261703

AFDMRX



Area Forecast Discussion

National Weather Service Morristown TN

103 PM EDT Thu Jun 26 2025



...New AVIATION...



.SHORT TERM...

(Today and tonight)

Issued at 134 AM EDT Thu Jun 26 2025



Key Messages:



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

southern and central TN Valley.



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

and evening. 



Discussion:



The large high pressure ridge that has been over the region will 

continue to be the dominant weather feature for one more day. 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 a degree to two lower compared to what we saw yesterday, but 

dewpoints will be slightly higher. Current obs are showing some 

locations with dewpoints in the mid to upper 70s, higher than 

what we have seen at this time the last few nights. Afternoon 

mixing will lower those values to lower and mid 70s, which will 

lead to a Heat Index around 105 for the southern and central TN 

Valley.



CAPE will continue to be plentiful in this hot and humid air mass. 

Convection should have no problem breaking through a weak cap in the 

early to mid afternoon, mainly in the higher terrain of the 

mountains and Cumberland Plateau. 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 

with PW values in the range of 1.5-1.7 inches will result in slow-

moving storms that dump heavy rainfall, potentially causing 

localized flooding. 



&&



.LONG TERM...

(Friday through Wednesday)

Issued at 134 AM EDT Thu Jun 26 2025



Key Messages:



1. Increasing moisture brings higher rain chances and slightly 

cooler temperatures through the weekend. Isolated severe storms and 

localized flash flooding are possible each day.



2. A cold front approaches the area Tuesday/Wednesday.



Discussion:



A weak tropical wave that is currently over the eastern coastline of 

Florida will make its way northwestward, and the large ridge will 

loosen its grip on the Southeast. This will bring greater moisture 

into the TN Valley through the weekend. 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. 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. With PW values rising into the range of 1.7-2 inches, 

any storms will be capable of producing heavy rainfall that causes 

localized flooding.



On Tuesday and 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, or if it pushes 

through. The latest models runs seem to be pointing more toward 

pushing the front to our south and east on Wednesday, which would 



&&



.AVIATION...

(18Z TAFS)

Issued at 1233 PM EDT Thu Jun 26 2025



Thunderstorms around TRI to start, and additional scattered storms

are expected around further south later this afternoon/early

evening. Will carry prob30 thunder groups all sites during the

period of highest probability. Brief gusty winds can be expected

with any thunderstorms.  Fog development later tonight will be 

possible especially TRI (given the rainfall there this afternoon),

so will include MVFR vsby in fog at TRI for now and lower vsby values

may occur. Outside any convection and the aforementioned fog at 

TRI, will have a VFR forecast all sites. 



&&



.PRELIMINARY POINT TEMPS/POPS...

Chattanooga Airport, TN             72  92  72  92 /  30  50  30  60 

Knoxville McGhee Tyson Airport, TN  71  90  71  91 /  20  50  30  60 

Oak Ridge, TN                       71  90  71  89 /  20  50  30  70 

Tri Cities Airport, TN              68  89  68  87 /  30  50  40  70 



&&



.MRX WATCHES/WARNINGS/ADVISORIES...

NC...NONE.

TN...Heat Advisory until 8 PM EDT /7 PM CDT/ this evening for 

     Anderson-Bledsoe-Bradley-Hamilton-Knox-Loudon-Marion-McMinn-

     Meigs-North Sevier-Northwest Blount-Northwest Monroe-Rhea-

     Roane-Sequatchie-West Polk.



VA...NONE.

&&



$$



SHORT TERM...DGS

LONG TERM....DGS

AVIATION...

