595
FXUS64 KMRX 071840
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
240 PM EDT Mon Apr 7 2025

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(This evening through Tuesday)
Issued at 223 PM EDT Mon Apr 7 2025

Key Messages:

1. Light rain late this afternoon into early evening especially
north and east, then a few light rain showers later tonight mainly
north and mountains with light snow showers possible over the
highest peaks.

2. Temperatures will be well below normal.

Discussion:

The upper level short wave trough to our west will move across the
area early tonight and off to our east, and a reinforcing shot of
colder air will push into the area behind a moisture starved cold
front later tonight. We will see some light rain ahead of the
approaching short wave late this afternoon into early evening
especially north and east, but this will push out quickly tonight.
As colder air pushes in later tonight on northwest winds there will
likely be enough orographic lift to wring out a few light showers
over the northern and eastern higher terrain later tonight, and by
this time it may be cold enough for a few snow showers over the
highest elevations. However, little or no accumulation is expected
even over the highest peaks. It will be quite cold with low
temperatures in the 30s in most valley locations, but enough wind
and clouds are expected to keep the chances for significant frost
low.

Monday will see cold surface high pressure to our northwest building
into our area, and despite quite a bit of sunshine temperatures will
be around 10 to 15 degrees below seasonal normals.

&&

.LONG TERM...
(Tuesday night through next Monday)
Issued at 223 PM EDT Mon Apr 7 2025

Key Messages:

1. Widespread frost/freeze conditions are expected Wednesday morning.

2. A weak system will bring a return to precipitation Thursday and
Friday.

3. Cooler temperatures arrive again late week into the weekend.

Discussion:

An upper trough will remain in place as surface high pressure
centers over the region Tuesday night. Strong subsidence will lead
to favorable radiational cooling conditions. Paired with below
normal upper level heights, widespread frost/freeze conditions will
develop Wednesday morning. The strong high pressure will keep
conditions dry with a slight warming trend relative to the previous
days high temperatures Wed afternoon.

Wednesday night into Thursday a shortwave will translate across the
upper Mississippi River Valley and into the Great Lakes region while
a ~1001mb area of low pressure progresses into the Ohio Valley. An
associated cold front will bring a return of precipitation chances
locally. Overall, instability looks minimal with this activity so
mostly showers are expected but it is possible we could have a few
rumbles of thunder. Latest NAM12 soundings suggest by late Thursday
afternoon mid-level lapse rates will increase to near 7.5-8.0 C/km
as cold air filters in aloft. With freezing levels falling to near
6kft it is possible we could see some graupel or small hail with
this activity. Precipitation chances will linger through Friday as
the surface system loses eastward momentum and nearly stalls along
the Mid-Atlantic coast.

Another period of cooler temperatures is expected Friday into Sunday
morning among the post-frontal airmass and H5 heights between 550-
560dam, however, rain chances will come to an end Saturday morning
as the sfc low finally ejects northeast. The upper trough will then
eject northeast being replaced with brief shortwave ridging late
weekend into the new work week. This should allow for a warming
trend with above normal temperatures by next week.

&&

.AVIATION...
(18Z TAFS)
Issued at 103 PM EDT Mon Apr 7 2025

Will see low clouds and some light rain/fog around early,
especially TYS and TRI. Conditions will be mainly MVFR at CHA, but
will be IFR/LIFR at times at TYS/TRI. Will see an improvement to
VFR late in the day/early evening, but some MVFR cigs will likely
move back into TRI for a period later tonight and may even make a
brief appearance at TYS (although will not include there for now).
The period should end VFR at all sites.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             40  59  35  67 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  37  55  31  66 /  10   0   0   0
Oak Ridge, TN                       35  55  31  65 /   0   0   0   0
Tri Cities Airport, TN              34  52  28  63 /  20  10   0   0

&&

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

$$

SHORT TERM...
LONG TERM....KRS
AVIATION...