304
FXUS64 KMRX 191751 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
1251 PM EST Wed Nov 19 2025

...New DISCUSSION, AVIATION...

.KEY MESSAGES...
Updated at 1232 PM EST Wed Nov 19 2025

- Favorable conditions for fog tonight across the entire area.

- Above normal temperatures expected through the weekend, with
  warmest days today through Friday.

- Scattered showers with potential for a few thunderstorms during
  the overnight. Mostly dry for the PM hours today. Rain chances
  will begin to increase again Thursday evening, with more
  widespread rain coverage Friday night into Saturday.


&&

.DISCUSSION...
Issued at 1232 PM EST Wed Nov 19 2025

The primary concern for this forecast will be tonight, as
conditions appear favorable for fog, with dense fog common in many
areas. The HRRR is really jumping on the reduced visibilities
area-wide tonight, which doesn`t happen very frequently. Dewpoints
this afternoon in the mid 50s to lower 60s suggest a high
crossover temperature for fog, and forecast lows will be several
degrees below current dewpoints. So the forecast will include
widespread fog in the grids, and a mention will be added to the
HWO. A DFA may be needed later; will let the evening shift
evaluatehow temperatures and dewpoints evolve through the
afternoon.

Currently, a weak front is aligned nearly E-W along the TN/KY
border into SW VA. There is some drier air behind this front, but
a weak wind field behind it will mean little in the way of
advection into East TN. A few sprinkles cannot be ruled out
through the evening in the northern half, but the chance of
measurable precip is very low due to the shallow nature of the
moisture. We will remain in an abnormally warm air mass on
Thursday, with highs in the mid 60s to mid 70s.

Better forcing and deeper moisture arrives Thursday night ahead of
a low pressure system over the Plains. Isentropic lift will
spread showers into the area Thursday night, followed by a lull in
precip Friday morning, then increasing showers and a slight chance
of thunderstorms with better QG forcing Friday afternoon and
night. A cold front approaching from the north will push into the
area Saturday, but given the strong positive tilt to the upper
trough, we will not have a strong push of cold air, and
temperatures will remain mild through Sunday.

Dry conditions area likely Sunday and Monday as a ridge builds
over the region, then another system will bring a chance of rain
in the Tuesday/Wednesday time frame.

&&

.AVIATION...
(18Z TAFS)
Issued at 1232 PM EST Wed Nov 19 2025

The set for fog overnight looks favorable, with a mild and moist
air mass over the area, with little wind tonight. Current
dewpoints are several degrees above the forecast low temps,
and expected clear/calm conditions will be good for radiational
cooling. Will have IFR to LIFR conditions at all sites tonight.
The low sun angle will result in a slow improvement in conditions
tomorrow morning, with at least MVFR conditions persisting until
11 AM to noon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             54  74  60  74 /   0  30  40  40
Knoxville McGhee Tyson Airport, TN  52  71  59  74 /   0  20  60  40
Oak Ridge, TN                       51  69  57  71 /   0  30  70  50
Tri Cities Airport, TN              51  66  53  69 /   0  10  60  50

&&

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

$$

DISCUSSION...DGS
AVIATION...DGS