267
FXUS64 KMRX 202355 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
755 PM EDT Sun Sep 20 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 746 PM EDT Sun Sep 20 2026

- Well above normal temperatures to persist into early this week. But
  relief is on the way, with a pattern change expected mid-week
  and much cooler temperatures to follow.

- Expect isolated to scattered showers today, with increasing
  coverage Monday through Wednesday.

- A few strong to severe storm with damaging winds could occur
  today and Monday, with damaging winds being the primary threat.
  Localized flooding will be possible each day through Wednesday
  as well.

&&

.DISCUSSION...
Issued at 133 PM EDT Sun Sep 20 2026

Currently another hot day with highs once again expected to top out
in the upper 80`s to lower 90`s across the eastern Tennessee Valley.
While there are a few showers out there as of early this afternoon
the coverage and intensity should both be lower than what we
experienced yesterday with weaker synoptic forcing and lower PWAT
values across the region. Similar conditions expected tomorrow and
Tuesday with more hot days expected. We`ll see more afternoon
showers and thunderstorms once again... Forecast soundings suggest
more instability on Monday and Tuesday leading to more vigorous
afternoon convection. We could see a few severe thunderstorms with
damaging straight line winds possible in the strongest storms. With
the multiple days of storms and very little movement in the mean
flow indicates the storms could sit over the same area for a while
leading to isolated flooding.

By the middle of the week we will FINALLY see a large scale pattern
change and usher in the first inklings of fall. Ridge builds in over
Canada and a trough sets up closer to home that will slowly meander
it`s way through the eastern half o the United States for the rest
of the week and into the weekend. This will much cooler temperatures
starting Wednesday and by Thursday through the weekend we should see
highs topping out only in the 70`s for every except southeast TN
where they may squeak across the 80 degree mark. This pattern will
also be fairly dry with a more Canadian airmass moving in.

Looks like we`ll finally get to open the windows this weekend!

&&

.AVIATION...
(00Z TAFS)
Issued at 746 PM EDT Sun Sep 20 2026

Main concerns for the 00z TAF cycle are fog potential again
tonight and how much, if at all, terminals will be affected by
SHRA/TSRA tomorrow. Regarding the fog, guidance is not
enthusiastic about it by any stretch for the overnight hours.
Still the pattern suggests the potential is there. Didn`t go quite
as aggressive with it tonight, opting for prevailing MVFR VSBY and
a TEMPO 1SM to hedge for potentially lower visibility and
ceilings, between 09z and 14z. Otherwise, greater convective
coverage is expected tomorrow. The better upper support for storms
will be in the north so PROB30 groups at KTYS and KTRI for SHRA
at the tail end of the period should suffice for now.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             95  72  95  71 /  20  10  40  40
Knoxville McGhee Tyson Airport, TN  93  71  92  69 /  10  10  40  40
Oak Ridge, TN                       92  70  91  68 /  20  10  50  50
Tri Cities Airport, TN              87  66  88  65 /  20  10  40  60

&&

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

$$

DISCUSSION...99
AVIATION...CD