221
FXUS63 KLMK 080204
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
904 PM EST Sun Dec 7 2025

...Forecast Update...

.KEY MESSAGES...

* Light rain/snow this evening and overnight will change over to
  light snow after midnight. Light accumulations of a coating to up
  to a half inch in spots is possible. Could create potential slick
  spots and hazards during the early morning commute.

* A series of system move across the Great Lakes Tuesday through
  Thursday that will feature a brief mid week warmup and chances of
  precipitation Wednesday and Thursday

* Coldest air of the season arrives Friday into the weekend with
  highs only in the 20s and lows in the teens and single digits over
  the weekend.

&&

.UPDATE...
Issued at 903 PM EST Sun Dec 7 2025

Interesting setup as we move into the overnight, and await a light
wintry mix across the area for Monday morning. The first feature
worth noting is a surface trough/front sliding southward over the
area now, with steady cold advection now in place across all of
southern IN and central KY on a north wind. Temperatures have been
steadily falling this evening, and expect below freezing
temperatures across southern IN by 1 to 4 AM, and across northern KY
by 3 to 5 AM EST. As cold air is undercutting at the surface
tonight, we do also have a progressive mid level shortwave that will
quickly slide through the area. Moisture has already begun pooling
in the 1000-700 mb layer ahead of this feature, and will continue
through the night.

The key to this forecast comes in two parts. 1.) How quickly do
temps fall below freezing while coincident with deep enough moisture
to precipitate? 2.) The depth of the moisture relative to the
thermal profile is marginal for ice introduction (and therefore snow
vs. freezing drizzle). Do think there is a clear window for rain
changing to snow where the bottom of the DGZ does get saturated, so
like the rain changing to snow theme that we already have going.
However, there does also appear to be some instances where we lose
deep enough saturation for a more reasonable shot at some light
freezing drizzle to mix in. This is evident on both forecast
soundings and time heights. So, there is some concern for some
patchy freezing drizzle, or at least drizzle occurring while ambient
air temperature is at or below freezing.

The good news is that we were able to warm up into the 45 to 50
degree range along with some sunshine this afternoon, so
surface/pavement temps will lag ambient air temperatures as
temperatures fall below freezing and into the upper 20s through the
Monday morning commute. Also, we look to lose the deeper saturation
after sunrise so any lingering very light precipitation should
mostly be finishing as temps fall into the upper 20s. This mindset
applies for most of our CWA, however our eastern counties over in
the Bluegrass are a bit more concerning.

Looking at forecast soundings and time heights, the residence time
of the deeper moisture, the deeper depth of saturation up to -15C,
and longer time of precipitation with temps in the upper 20s all
suggest that a few more impacts, and slightly higher amounts are
more likely in this area. Plan to bump up some amounts closer to 1
inch, and consider a Winter Weather Advisory for some of our E/NE
Bluegrass counties in coordination with JKL. right now, the plan is
to add Scott, Fayette, Harrison, Nicholas, Bourbon, and Clark to a
mainly impact based Winter Weather Advisory for a coating to 1" of
accumulation during the Monday morning commute.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 405 PM EST Sun Dec 7 2025

Cold front will work across the area tonight into tomorrow bringing
with it some light precipitation ranging from a mix or rain/snow to
even a period of light snow, mainly along the I-64 corridor into the
Bluegrass with mainly light rain showers along and south of the
WK/BG parkways towards the KY/TN border. Sfc boundary currently
stretches from Columbus, OH to Bloomington, IN to just south of St.
Louis, MO. There has been very limited moisture out ahead of this
front. Light precipitation will start to develop as we go overnight
with a possible mix of rain/snow to all snow along the I-64 corridor
and north of the the parkways overnight. A coating to possibly a
half inch of snow could accumulate on grassy and elevated surfaces.
Most of the activity is expected after midnight into the pre-dawn
hours. While impacts are not high, with the fact that we could see
light accumulation before and even into the morning commute around
the Lexington area, will continue the special weather statement
across most of the Bluegrass. The main struggle with some of the
precipitation, especially snow, is that model sounding don`t show
much saturation in the DGZ. This could produce some pockets of
drizzle or flurries. Temperatures will fall behing the front going
from the upper 30s to low 40s around sunset to the mid/upper 20s and
low 30s across the south.

We will be mostly dry and colder to start the week with some
lingering cloud cover behind the front during the day. Clouds will
clear from the north to the south with a northerly flow advecting in
the colder air. Highs will be about ten degrees colder with highs in
the 30s.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 405 PM EST Sun Dec 7 2025

Main focus in the long-term will be a series of two system during
the middle of the week, a brief warm up ahead of the first system
Tuesday and Wednesday with the coldest air of the season arriving
for the end of the week and into the weekend.

High pressure will be over the northeastern CONUS Tuesday allowing
for warm air to advect as winds become more southerly. The first in
a series of systems will be passing by to the north on Tuesday,
tightening up the sfc pressure gradient and increasing winds over
the area. Could see wind gusts of 15 to 25 mph and highs back into
the mid/upper 50s. A second strong sfc low coming out of Canada will
move a bit further south than the system on Tuesday. This will
tighten the sfc pressure gradient even more and advect in more
warm/moist air from the south. Temperatures will warm into the upper
40s/low 50s during the day Wednesday with gusty winds between 20 to
30 mph. Associated sfc cold front will also be working through
during the day Wednesday as precipitation along and ahead of this
boundary falling as mainly rain. The third disturbance on Thursday
will be associated with a shortwave trough that will bring a wintry
mix of rain/snow followed by very cold air. While we could see some
wintry precipitation, current thought is overall impacts from these
three disturbances will be limited.

Upper ridging will amplify over the western US as a deepening trough
sets in over the eastern US. Strong Canadian high pressure builds in
behind the departing system the coldest air of the season is
expected to arrive. Highs are expected to be in the low/mid 30s on
Friday with highs only in the 20s over the weekend and low overnight
temperatures in the teens and single digits Saturday and Sunday
morning.

&&

.AVIATION /00Z TAFS THROUGH 06Z TUESDAY/...
Issued at 652 PM EST Sun Dec 7 2025

Conditions have returned to the MVFR range this evening at
SDF/BWG/HNB sites, and will likely do so soon at LEX/RGA as the next
weather making system moves into the area. A surface cold front is
currently passing through the area, and has cleared all sites except
BWG, which it will do so shortly. So, expect a pretty steady N wind
through this cycle, mostly between 10 and 15 mph.

Ceilings and overall conditions are expected to deteriorate through
the night, along with a light wintry mix across the northern TAF
sites. Do expect IFR to prevail for a period overnight into the
morning hours, most likely at the northern TAF sites. Conditions
should improve back to the VFR range late in this forecast cycle,
but not before much of Monday is spent in low MVFR conditions.
Surface winds do start to slacken out of the north late afternoon
into the evening. Light precipitation ends shortly after sunrise
from west to east.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Winter Weather Advisory from 2 AM to 10 AM EST Monday for
     KYZ036-037-041>043-049.
IN...None.

&&

$$

UPDATE...BJS
SHORT TERM...BTN
LONG TERM...BTN
AVIATION...BJS