020 
FXUS64 KMRX 011833
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
233 PM EDT Thu Oct 1 2026

...New DISCUSSION...

.KEY MESSAGES...
Updated at 232 PM EDT Thu Oct 1 2026

- Chances for showers and isolated storms will increase tomorrow and 
through the weekend with locally heavy rainfall possible. 

- Drier and cooler conditions will return next week. 

&&

.DISCUSSION...
Issued at 232 PM EDT Thu Oct 1 2026

Currently, broad ridging is in place across the eastern U.S. with a 
5,920m 500mb high along the Carolina Coast just west of Bermuda high 
pressure. A closed low is also ejecting just east of the Rockies 
with a surface low also having developed. For our local area, this 
pattern has continued the dry and warmer trend seen in the past 
several days to start the period. Heading into tonight, the closed 
low will lift to the north with the surface low weakening. 
Increasing frontogenesis is expected to the north and east following 
continued southerly flow from the Gulf and approaching Canadian high 
pressure. This will also lead to increasing moisture. 

During the day on Friday, a downstream upper jet will move to our 
north with the surface front approaching the Ohio River Valley. This 
will increase overall synoptic-scale lift with sufficient moisture 
leading to a return of rain chances, mainly north of Interstate 40. 
With poor lapse rates below 5 C/km and instability of 250 to 500 
J/kg, at least isolated storms can be expected. By Saturday, another 
downstream jet will move closer to the region, along with the 
surface frontal boundary. By this time, significant moisture will be 
in the region with PWAT values approaching 1.8 inches, near max 
values for this time of year. Mid-level lapse rates are also 
expected to rise up to 5.5 C/km. By Sunday, the front will remain 
nearby but with stronger upper divergence aloft. Given these 
indications, higher area-wide rain can be expected with locally high 
amounts possible. Based on what the RRFS is showing, coverage looks 
to be higher on Sunday, in line with the upper jet strength. 
Isolated flooding remains possible, but this will depend on which 
places see repeated rainfall. 

By Monday, the high pressure to the north will be progressing into 
the Great Plains, pushing the frontal boundary to our south. Other 
than some lingering chances in the south early, drier and cooler 
conditions can be expected. This will be especially true by Tuesday 
night into Wednesday morning when the high is just to our north and 
east. Overall, daytime highs look close to normal in the 70s, but 
overnight lows could drop well into the 40s with the radiational 
cooling. 

&&

.AVIATION...
(18Z TAFS)
Issued at 106 PM EDT Thu Oct 1 2026

Main concern is potential of fog development at TRI. Any steam fog
may move into the terminal early Friday morning. Confidence is too
low to include. Otherwise, VFR conditions with surface and upper 
ridging keeping things quiet.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             67  91  70  87 /   0  30  20  60 
Knoxville McGhee Tyson Airport, TN  65  89  68  83 /   0  20  40  70 
Oak Ridge, TN                       64  87  67  81 /   0  30  50  70 
Tri Cities Airport, TN              59  85  64  77 /   0  10  50  80 

&&

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

$$

DISCUSSION...BW
AVIATION...DH


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