254 
FXUS64 KMRX 111749
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
149 PM EDT Sat Jul 11 2026

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Updated at 140 PM EDT Sat Jul 11 2026

- Multiple rounds of showers and thunderstorms remain possible
  through Sunday night. Any areas impacted by repeated storms
  could see significant rainfall and experience flash flooding. As
  such, a Flood watch remains in effect through Sunday night.

- A few strong to severe storms could occur today and Sunday. The
  primary threat would be gusty winds.

- More typical summer weather Tuesday onwards with normal 
  temperatures and only a low PM chance of thunderstorms.

&&

.DISCUSSION...
Issued at 140 PM EDT Sat Jul 11 2026

Synoptically speaking, a semi-closed upper trough situated from the 
Ohio valley westward to the Ozarks of Missouri, will continue to 
drift southward over the next 48 hours or so. Meanwhile, upper 
ridging will expand from the Rockies northeastward into the northern 
plains during that same period, ultimately creating a quasi-rex 
block type pattern over the Great Lakes and Ohio valley areas as the 
aforementioned trough continues to meander south and gets trapped 
beneath the expanding ridge. Locally, this means continued chances 
for shower and thunderstorm activity as impulses emanate eastward
from that upper trough/semi-closed low to our WNW, until this 
feature finally pushes south of the region by Tuesday. Given the 
high PWAT air mass in place and storm motions being largely 
parallel to upper flow, training convection will and the risk of 
flash flooding will continue to be a risk for much of the 
forecast area through Sunday night. As we get into Monday and 
Tuesday, the upper trough axis becomes increasingly situated 
overhead, meaning the focus for stronger convection and heavier 
rains will shift increasingly south of us. For these reasons, I 
don't see a need to extend the Flash Flood Watch beyond Sunday 
night, but I did change the expiration time to 06z Monday to 
account for one last batch of late evening/nocturnal storms that 
might move through tomorrow.

With regards to severe storms potential this afternoon and evening, 
I think our chances are fairly limited. SPC mesoanalysis page 
indicates there is somewhere in the neighborhood of 1,500 J/kg of 
MLCAPE in the southern valley. This seems reasonable given the 
current radar mosaic and strong storms along the TN/GA border area 
this afternoon. Those storms also have a light southward motion to 
them which should carry them out of our CWA by 3-4pm. Further north, 
the atmosphere was really worked overnight and earlier today, and 
cloud cover through the day has limited instability. All in all, I 
think the severe chances are low through this evening. CAM guidance 
indicates little in the way of additional convection developing 
later on too which lends confidence to my thoughts here. However, 
it's not as optimistic on the flooding side. Another round of 
nocturnal convection is expected in our CWA tonight and then again 
Sunday night. It's difficult to say exactly where storms may align, 
but rainfall amounts have exceeded 3-5" in a few spots over the last 
24 hours that have been affected by training storms. It's not out of 
the question to say something similar could happen tonight or 
Sunday, and thus the risk of flooding continues. There is just 
low confidence in where exactly the greatest threat resides.

As mentioned, by Tuesday the upper low shifts south of us and we
lose the focus for repeated storms and heavy rains. Rain chances
remain in the forecast though, primarily for diurnally driven
afternoon showers and thunderstorms. With the ridge building to
our north these will be more scattered in nature. We'll also warm
up moving into the mid/late week time frame, with highs climbing
back into the upper 80s.

&&

.AVIATION...
(18Z TAFS)
Issued at 140 PM EDT Sat Jul 11 2026

Expect a mix of VFR and MVFR conditions through the period, with
MVFR or lower expected in SHRA/TSRA. Expect the most likely time
for convection to affect terminals after 06z tonight as another
round of nocturnal storms move into East Tennessee from the WNW. 
Have attempted to time that in with PROB30 groups to limit how 
much SHRA/TSRA are mentioned in the TAFs.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             72  86  70  83 /  50  70  70  90 
Knoxville McGhee Tyson Airport, TN  70  84  69  83 /  60  80  80  90 
Oak Ridge, TN                       70  83  68  83 /  60  70  80  90 
Tri Cities Airport, TN              66  81  66  82 /  70  70  60  80 

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...Flood Watch through late Sunday night for Cherokee-Clay.

TN...Flood Watch through late Sunday night for Anderson-Bledsoe-
     Blount Smoky Mountains-Bradley-Campbell-Claiborne-Cocke 
     Smoky Mountains-East Polk-Grainger-Hamblen-Hamilton-Hancock-
     Hawkins-Jefferson-Johnson-Knox-Loudon-Marion-McMinn-Meigs-
     Morgan-North Sevier-Northwest Blount-Northwest Carter-
     Northwest Cocke-Northwest Greene-Northwest Monroe-Rhea-
     Roane-Scott TN-Sequatchie-Sevier Smoky Mountains-Southeast 
     Carter-Southeast Greene-Southeast Monroe-Sullivan-Unicoi-
     Union-Washington TN-West Polk.

VA...Flood Watch through late Sunday night for Lee-Russell-Scott VA-
     Washington VA-Wise.

&&

$$

DISCUSSION...CD
AVIATION...CD


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