247
FXUS63 KLMK 040543
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1243 AM EST Thu Dec 4 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

* Brief light snow or flurries late tonight into Thursday morning
  across southern IN and northern KY. No accumulation to a few
  tenths of an inch will be possible.

* Thursday night into Friday morning, a system will move south of
  the region and bring mixed precip and snow to southern Kentucky.
  Confidence is increasing a light accumulations and significant
  accumulations are not expected.

* Messy weather pattern will continue through mid next week, where
  light precip will be possible.

&&

.UPDATE...
Issued at 905 PM EST Wed Dec 3 2025

This evening, we have light radar returns mainly across southern IN,
though most if not all of this is not reaching the ground. The low
stratus has continued to erode back to the northwest as WAA
continues in the sfc-925 mb layer. This warm advection is taking
place ahead of a sfc cold front which is currently analyzed from the
lower peninsula of MI down into OK. Ahead of this front,
temperatures should remain fairly steady tonight given weak
southerly flow. As the front begins to sink across the area after
midnight, low clouds should increase again from NW to SE. There may
be enough low-level moisture for some patchy fog to develop, and
given temps at or below freezing across the area, a few slick spots
may develop if fog in denser patches of fog.

Just behind the front, there could be a few flurries or light snow
showers early Thursday morning along and north of I-64, though
latest hi-res guidance has backed off of this somewhat. At most,
would expect what was mentioned by the previous forecaster, with a
light dusting possible across southern IN.

The forecast is on track at this time. Made minor updates to
temperatures and PoPs overnight.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 249 PM EST Wed Dec 3 2025

Moisture concentrations below 925mb are currently observed in model
forecasts and area soundings, sustaining a layer of low stratus
clouds over the lower Ohio Valley. At this time, a clearing trend is
noted, progressing from the southeast toward the northwest. The
eastern and southern portions of the region are anticipated to
experience several hours of predominantly clear skies, while the
remainder of the area will observe at least partly cloudy
conditions. Given the current sky cover and the limited duration of
insolation following cloud dissipation, maximum temperatures are
expected to remain near or below the freezing point.

Tonight, a shortwave trough will traverse the region, accompanied by
an advancing cold front. A 30-35 kt LLJ, coupled with a mid and
upper-level jet, will create a favorable jet structure to induce
atmospheric lift despite minimal available moisture. Consequently,
the possibility of flurries exists across the entire area, and light
snowfall is forecast for southern Indiana and northern Kentucky
during the early morning hours. Impactful accumulation is not
anticipated; rather, amounts are expected to range from a trace up
to a few tenths of an inch. With light winds and low-level moisture,
the development of very patchy freezing fog is possible, although
its extent may be limited by the overcast conditions associated with
the frontal passage. Overnight low temperatures are forecast to be
in the mid-20s.

High pressure will subsequently build in behind the cold front and
become centered over the northern Ohio Valley. This pattern will
establish a prevailing drier northerly and northwesterly surface
flow on Thursday. The low stratus layer will begin to exit the
region Thursday morning, from the northwest to the southeast. CAA is
expected to prevent high temperatures from rising above freezing
across most of the region.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 249 PM EST Wed Dec 3 2025

===== Thursday - Friday =====

Flow aloft is expected to become more zonal during this period,
introducing a contiguous stream of vorticity across the region. A
weak trough will traverse the area on Friday, displacing surface
high pressure to the east. This weak trough will introduce a low-
pressure system over the Southeastern CONUS. The lower Ohio Valley
will reside on the northern periphery of this system, situated
within a zone of frontogenesis. Furthermore, a weak LLJ will
contribute to lift, interacting with limited low-level moisture.
This setup is conducive to producing snowfall across southern and
eastern Kentucky from Thursday night into Friday.

With the forecast now within the range of Hi-Res guidance, the
expected snowfall accumulation ranges from a Trace to a few tenths
of an inch. Isolated areas in the Lake Cumberland region could
potentially observe amounts approaching 0.5 inches. The GFS
continues to indicate less snowfall, while the Euro presents a more
aggressive solution. Examination of the EFI reveals elevated
probabilities and a shift-of-tails signal over southern Kentucky.
Considering the early stage of the season, this shift-of-tails
signal is not a significant concern; however, it warrants continued
monitoring, particularly regarding the Friday morning commute.


===== Weekend - Next Week =====

A disorganized, predominantly zonal flow aloft will persist across
the region, where minor atmospheric disturbances may traverse the
area and yield light precipitation. Despite the unorganized nature
of the pattern, it will remain transient, resulting in intermittent
light precipitation while largely maintaining dry conditions.

A more significant trough is projected to move through on Monday,
increasing the probability of mixed rain and snow showers. Ensemble
and deterministic guidance indicate considerable variability in
potential outcomes, but this system could bring a few tenths of an
inch of snowfall. By the middle of the week, temperatures are
expected to moderate to near-normal values, reaching the upper 40s
and lower 50s.

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 1242 AM EST Thu Dec 4 2025

Restricted flight categories are forecast to continue as a cold
front approaches and gradually passes through the region today. Cigs
are expected to lower back down to MVFR and IFR overnight, which are
likely to persist through majority of the forecast period. A band of
light snow will be sliding north of the area this morning, and could
come within the nearby proximity of SDF. However, confidence is not
high enough to mention in TAF, so a dry forecast will continue. Kept
a more pessimistic forecast going for later today with cigs, and
believe we`ll remain in at least MVFR through the end of the period.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.

&&

$$

UPDATE...CSG
SHORT TERM...SRW
LONG TERM...SRW
AVIATION...CJP