898
FXUS63 KLMK 110526
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1226 AM EST Thu Dec 11 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

* Lingering flurries and snow showers tonight may lead to patchy
  slick spots Thursday morning.

* A more significant wintry system is possible Thursday night into
  Friday morning, with chances for greater than 1" of snow
  continuing to increase across north central KY and southern IN.
  Travel impacts are likely along and north of the I-64 corridor
  Friday morning.

* Saturday night into Sunday morning, another system will bring
  snowfall to similar areas as Thursday night. Amount of snowfall is
  still uncertain, but chances of around 1 inch of snow is high.

* Very cold airmass will move into the region on Sunday through
  Monday, as lows will be in the single digits and highs on Sunday
  in the teens and low 20s.

* Temperatures will steadily warm Monday afternoon through mid
  next week.

&&

.UPDATE...
Issued at 943 PM EST Wed Dec 10 2025

The upper level trough axis shifts east of the area tonight. Cold NW
flow continues, with moisture confined to the lowest 150-200 mb of
the atmosphere. The top of the moist layer just reaches into the
bottom part of the dendritic growth zone. LVX radar shows very
light, isolated returns as of this writing. Isolated, brief light
snow and flurries will be possible late tonight. However, the
limited moisture depth will keep snow production to a minimum.

Temperatures have gradually fallen into the low to mid 30s. NW winds
remain rather breezy, with gusts of 20-25 mph. Sfc winds will
gradually diminish early Thu morning as the pressure gradient
relaxes, and temperatures will settle into the mid/upper 20s. A few
slick spots will be possible overnight and early Thu as temps dip
into the 20s.

After a break in the action on Thursday, our well-advertised and
more significant wintry system looks on track for Thursday night. An
area of low pressure is forecast to drop southeast into the Lower OH
Valley, with an impactful snow band setting up to the northeast of
the low. Impactful snow accumulations are most likely across
southern Indiana, portions of north-central Kentucky, and the
Bluegrass Region. Snow accumulation of 1-4" looks possible northeast
of a line from French Lick to Richmond, with the highest amounts
concentrated from Madison IN southeast through the northern
Bluegrass.

Small north-south jogs of the sfc low and snow band remain possible,
which could have a big impact on snow accumulation and impacts in
many communities. For example, a very sharp cutoff in snow is
expected along the southwestern flank of this system. For that
reason, and after collaboration with neighboring NWS offices, a
Winter Weather Advisory has been issued for the highest confidence
areas most likely to see at least 1-2+ inches of snow. The Winter
Weather Advisory includes Salem IN southeast through Lexington KY,
and areas to the northeast. Some wintry impacts are certainly
possible immediately to the southwest of the current advisory, and a
slight expansion is possible in future updates if forecast
confidence increases in impactful accumulations.

The Winter Weather Advisory is valid 7 PM Thursday through 10 AM EST
Friday.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 400 PM EST Wed Dec 10 2025

This Afternoon through Tonight...

A surface cold front is pushing across central KY at this hour, and
should clear the area later this afternoon. Along the front,
scattered rain showers mixed with ice pellets have developed, with
some of the heavier showers producing isolated 40-50 mph wind gusts.
Behind the front, llvl cold advection is spreading across southern
IN, with temperatures falling from the mid 40s into the upper 30s
over the past few hours. Breezy W/NW winds are also present outside
of showers, with sustained winds of 10-20 mph and gusts of 25-35 mph
continuing this afternoon before settling down this evening.

Later this afternoon into this evening, low-level lapse rates should
steepen with saturation lingering from the sfc to around 800 mb. As
temperatures continue to cool this evening, this should allow
saturation to reach to around -10C, which should be just sufficient
for some isolated to scattered development of snow showers. While
coverage of flurries and snow showers should be greatest east of I-
65, most if not all of the CWA has a chance to see a brief snow
burst this evening into tonight which could drop a quick dusting to
a few tenths of an inch of snow. There may also be
enhancement/greater coverage of snow showers across our counties
which border the Cumberland Plateau (i.e.
Cumberland/Clinton/Russell/Casey/Lincoln). As the sfc low continues
to push east tonight, sfc high pressure axis will begin to creep in
from the west, leading to lighter west winds by sunrise Thursday.
Additionally, moisture should become shallower late tonight, which
should assist in bringing an end to any snow showers/flurries by mid-
morning tomorrow. Where any snow showers occur, isolated slick spots
will be possible tonight into tomorrow morning as temperatures fall
into the 20s.

Thursday...

The daytime hours on Thursday should bring a period of relative
quiet weather-wise as sfc high pressure slides into the Tennessee
Valley. With the high mainly staying to the SW of the area, we won`t
be able to get strong warm southwesterly return flow, with lingering
clouds also helping to keep temperatures down. Expecting highs on
Thursday to range from the low 30s north of I-64 to around 40 along
the TN border, where there is a better chance of briefly clearing
skies. Any clearing which does occur should be short-lived as mid-
and high clouds increase from the NW Thursday afternoon ahead of the
next approaching system.

Thursday Night and Friday...

Thursday afternoon, an upper-level shortwave dropping out of the
Canadian prairies will interact with a sfc low near the NE/SD
border. A strong NW-SE baroclinic zone will extend from the Dakotas
down to the southeast US coast, cutting right across Indiana and
Kentucky. A typical clipper-type system will descend along this
gradient from the upper Midwest into the lower Ohio Valley Thursday
night into Friday, with an effective warm front extending out ahead
of the sfc low center. It will be along and northeast of this warm
front where precipitation develops Thursday afternoon into the
evening, with mid-level warm frontogenesis supporting enhanced bands
of precipitation, with soundings suggesting p-types almost
exclusively being snow, at least through Friday morning. South and
west of the warm front`s position, a loss of deep moisture will lead
to little in the way of precipitation. As a result of enhanced snow
bands right in the vicinity of the warm front, there will likely be
quite a sharp cutoff in snow amounts from NE to SW across the area.

Today`s model guidance leaves quite a bit of lingering uncertainty
in snowfall amounts across portions of the LMK CWA. Across south
central and southwest KY, there is still fairly high confidence that
the band of snow will remain to the north, with little to no
snowfall expected. The picture is more uncertain across north
central KY and southern IN. While the 12Z GFS/ECMWF/Canadian and
their ensembles have trended south with the band of snow, the hi-res
guidance remains displaced farther to the northwest. At this time,
probabilities of greater than 1" of snow exceed 50% roughly
northeast of a line from Huntingburg, IN to Mount Vernon, KY, while
the 80% probability contour of greater than 1" of snow is only about
25-30 miles to the northeast. This further supports the idea of a
sharp gradient in snowfall amounts. It`s also worth noting that the
chances for greater than 4" of snow have increased considerably
today across portions of southeast IN and the KY Bluegrass, with
probabilities now approaching 50%. Per collaboration with
surrounding offices, we`ve held off on issuing any headlines at this
time; however, it is increasingly likely that a winter weather
advisory - and possibly a localized winter storm warning, may be
needed for the snow potential Thursday night into Friday morning.

During the day on Friday, the sfc low should track across south
central KY, resulting in a sharp temperature gradient from north to
south across the region. Snow should come to an end across the KY
Bluegrass by mid-to-late morning, with mostly cloudy skies
continuing through the rest of the day. Some clearing may occur
along the TN border, especially if the sfc low tracks farther to the
north. Temperatures should range from the upper 30s along and north
of I-64 to the low 50s (!) along the TN border.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 400 PM EST Wed Dec 10 2025

Weekend...

Surface low pressure over the Great Lakes will drag a cold front
through the lower Ohio Valley on Saturday morning. As this system is
not mature and stacked aloft, the CAA and troughing will be delayed
behind the front. Troughing associated with the system will deepen
over the Ohio Valley and push through on Sunday. If this setup
continues over the next several forecast periods, it will be an
interesting case. Aloft, a strong jet will place the northern half
of the region under the right entrance region and a 30-35kt LLJ will
help supply some lower level lift. Coinciding with long range
guidance suggesting elevated potential vorticity and a area of
frontogenesis. This setup will provide deep layer lift to deep layer
moisture (PWATs around 0.55-0.6 inches which is near the 80%
percentile of climatology). This setup could allow for efficient
snow production Saturday into Sunday. There is great spread between
ensembles and deterministic model guidance on snowfall amounts,
specifically over the northern half of the region. Over the southern
half of the region, there is good confidence in no snow to a trace
of snowfall. Will continue to monitor this system, as it could be
quite impactful to the northern half of the region if higher snow
total probabilities continue.

Additionally, as the main troughing pushes through the region, very
strong CAA quickly drops temperatures. Sunday morning, we could see
lows in the single digits over northern areas and low teens over
southern areas. A strong surface high will quickly build in from the
west, keeping pressure gradients and a weak LLJ over the region.
This will allow for breezy conditions on Sunday, making it feel
colder with minimum wind chills in the near or below zero range.
Some areas in southern Indiana may see wind chills near -5. It is
possible that a cold weather advisory may be needed for Sunday
morning. High temperatures on Sunday will be in the teens and 20s.
These cold max temperatures will be close to the record for Sunday.


Monday Through Mid Next Week...

High pressure will be centered over the region on Monday morning,
leading to weak winds and clear skies with continued CAA. This will
allow temperatures to efficiently cool and low temperatures to be in
the single digits over most of the region. However, since winds will
be calm to light, wind chills will be close to the temperature.
Impacts will mostly be to the Monday morning school bus stop timing
which will be quite chilly. Make sure to have extra layers on this
day.

From Monday afternoon through the middle of next week, ridging will
likely build over the region and high pressure will remain. This
will allow continued dry conditions, sunny skies, and warming
temperatures.


Overall Forecast Confidence in the Long Term...

Confidence has generally increased across the board. Deterministic
guidance and ensembles are beginning to convergence on setup and
timing. Though there still remains quite a spread on snowfall
amounts for Saturday into Sunday.

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 1225 AM EST Thu Dec 11 2025

MVFR ceilings continue at the TAF sites this evening, and are
expected to persist through the overnight into Thursday. Some brief
improvement back to VFR is possibly through the afternoon and early
evening hours, however look for conditions to quickly deteriorate to
low MVFR or even IFR shortly after sunset as a clipper system brings
snowfall to our area. BWG will mostly be spared from this late drop
in conditions, and expect them to stay VFR under an overcast mid
deck of clouds and perhaps some very light wintry mix.

Surface winds tonight stay pretty steady out of the NW, however will
gradually weaken and go WSW through the day, and then light SE by
later Thursday evening.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Winter Weather Advisory from 7 PM this evening to 10 AM EST
     Friday for KYZ031>037-039>043-048-049.
IN...Winter Weather Advisory from 7 PM this evening to 10 AM EST
     Friday for INZ077>079-092.

&&

$$

UPDATE...EBW
SHORT TERM...CSG
LONG TERM...SRW
AVIATION...BJS