368 
FXUS64 KMRX 041849
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
249 PM EDT Tue Aug 4 2026

...New DISCUSSION...

.KEY MESSAGES...
Updated at 236 PM EDT Tue Aug 4 2026

- Scattered showers and storms are expected this afternoon, with
  greatest coverage in and along the higher terrain. A few storms 
  could produce strong gusty winds, localized flooding, and small 
  hail. 

- Daily chances of showers and storms will continue each day
  through the forecast period, primarily favoring the afternoon
  and evening hours. A low chance for localized flooding exists
  each day.

- Near normal temperatures are expected for the next several days.

&&

.DISCUSSION...
Issued at 236 PM EDT Tue Aug 4 2026

An upper level low has developed over the southeastern CONUS, while 
a shortwave trough is ejecting northeast in vicinity of Nova Scotia 
and an additional trough digs into the northern Plains. A weak 
southern stream vort max will promote a retrograding stationary 
boundary in the Piedmont this afternoon. The vort max and front will 
aid diurnal convective initiation within an environment of ~1500J/kg 
MLCAPE, 1.5-1.7 PWs, and weak steering flow. Latest 1 hr ffgs range 
from 1.4-1.8 inches in the foothills and East Tennessee mountains, 
increasing to around 1.8-2.3 inches in southeast Tennessee and 
southwest North Carolina. While on the weaker side, latest 
mesoanalysis depicts a local increase in sfc-H85 convergence where 
storms have notably strengthened over the last 30 minutes. Main 
threats for this afternoon will be isolated strong to damaging winds 
gusts and localized flooding, but some of the tallest storms could 
exhibit small hail as well. 

Upper low is expected to remain in place across the region tomorrow 
afternoon, and slowly phase into mean flow aloft Thursday into 
Friday. However, the aforementioned troughing over the Northern 
Plains will be working into the Great Lakes region, maintaining weak 
upper level divergence across the southern Appalachians. Diurnal 
heating in a moist environment will ultimately promote continued 
chances of diurnal convection through at least the remainder of the 
weekend. With each day, isolated flooding could pose a threat with 
any slow moving storms that track over already saturated soils or 
want to latch onto terrain features. While the potential for some 
valley convection is possible, the greatest coverage is largely 
expected in areas of enhanced orographic lift. 

As we head into next week, the latest ECMWF depicts enhancement of 
the low-level jet across the the northern Ohio Valley. This will 
continue the chance for daily showers and storms, but long range 
deterministic models are not in agreement with the coverage. GFS 
is more bullish while the ECMWF is and the lower side. Latest NBM
is bridging that gap with 40-50% PoPs. CIPS analogs keep the 
better chances for severe weather to our north and east in closer 
proximity to the strong synoptic forcing and enhanced shear.

&&

.AVIATION...
(18Z TAFS)
Issued at 138 PM EDT Tue Aug 4 2026

Scattered thunderstorms expected for the first 4-6 hours of this
TAF cycle. Most likely to be impacted will be KTYS/KTRI. If an
airport gets a thunderstorm it would likely last for 30-60
minutes. If moderate rain occurs it could cause morning fog, but
will not any into the TAFs until this actually happens.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             71  88  72  90 /  20  60  20  60 
Knoxville McGhee Tyson Airport, TN  70  86  71  87 /  20  60  10  60 
Oak Ridge, TN                       70  86  70  87 /  20  50  10  70 
Tri Cities Airport, TN              67  83  67  83 /  10  60  20  70 

&&

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

$$

DISCUSSION...KRS
AVIATION...99


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