804
FXUS63 KLMK 100609
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
109 AM EST Wed Dec 10 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

* Windy conditions are expected through Wednesday, with widespread
  wind gusts of 25-35 mph and isolated gusts to 40 mph likely.

* A cold front will bring rain to the region tonight into Wednesday.
  Precipitation will transition to scattered snow showers and
  flurries Wednesday night, with light accumulations and slick spots
  possible Thursday morning.

* A more significant wintry system is possible Thursday night into
  Friday morning, which could bring accumulating snowfall to
  portions of north central KY and southern IN.

* Another shot of colder air arrives this weekend.

&&

.UPDATE...
Issued at 916 PM EST Tue Dec 9 2025

A deep ~990 mb sfc low is moving southeast over MN this evening.
This potent system is forecast to continue rotating ESE across
southern WI/Lake Michigan tonight into tomorrow morning. Breezy SW
winds will continue overnight, with gusts likely to increase after
11 pm. Wind gusts of 30-40 mph are likely late tonight through mid-
afternoon Wednesday. Isolated peak gusts over 40 mph seem like a
good bet, but the confidence is not quite high enough to go with a
broader Wind Advisory. But will keep the Special Weather Statement
going, and we continue to message possible 40+ mph gusts in HWO and
messaging/graphics.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 423 PM EST Tue Dec 9 2025

Mostly sunny skies, breezy S/SW winds, and milder temperatures are
observed across the area this afternoon as the region sits in
between high pressure over the southeast US and deep low pressure
over the Dakotas. For the rest of this afternoon and evening,
relatively mild and breezy conditions will continue, with winds
becoming a bit less gusty around and just after sunset as the
boundary layer becomes more stable. While clouds will increase from
the north later this evening, dry conditions are expected to
continue until early Wednesday morning.

Tonight, the upper level shortwave associated with the deep low over
the Dakotas will drop to the SE toward Lake Michigan. The pressure
and height gradient over the Ohio Valley will continue to strengthen
overnight, leading to the development of a 60-70 kt H85 jet which
will move across southern IN and northern KY during the pre-dawn
hours. While breezy winds will continue at the surface through the
nighttime hours, model soundings show poor lapse rates between the
sfc and the LLJ, suggesting that mixing of faster winds aloft will
be limited overnight. With this being said, chances for rain showers
will increase after 06Z Wednesday, and often times stronger winds
will be brought down to the surface with the initial wave of
precipitation. As a result, wind gusts should generally range from
25 to 35 mph overnight, but isolated 40+ mph wind gusts will be
possible in heavier rain showers. With strong southerly winds and
increasing cloud cover expected overnight, temperatures will
struggle to cool, with temperatures remaining fairly steady in the
upper 30s and low 40s.

Precipitation amounts with this system will be fairly light overall,
as access to Gulf moisture will be limited, as is typical with
clipper-type systems. Hi-res model guidance suggests that most of
the showers should be concentrated along or just ahead of the cold
front, moving across the area Wednesday morning. During the
afternoon and evening hours, cold advection and steepening low-level
lapse rates should lead to showers becoming more scattered, with
cooling aloft gradually increasing the likelihood of showers mixing
with or changing to snow. Highs tomorrow should be reached during
the late morning and early afternoon hours, with temperatures
falling later in the day as winds swing around to the NW. Winds will
remain gusty during the day on Wednesday, with better mixing leading
to continued 30-40 mph wind gusts until late afternoon.

Wednesday evening into Wednesday night, low-level moisture will
linger with the upper trough still spinning overhead. Where pockets
of deeper moisture exist, there will likely be bands of flurries or
light to moderate snow showers. Coverage of these snow bands will be
isolated to scattered, with the greatest coverage likely occurring
across the Bluegrass region; however, within the heavier bands, a
quick coating to half inch of snowfall will be possible. With
temperatures falling into the mid-to-upper 20s Thursday morning, any
locations which receive snow Wednesday night could see slick road
conditions during the first part of the day on Thursday.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 423 PM EST Tue Dec 9 2025

Thursday should be the transition period between the clipper system
which moves through the region tomorrow and a subsequent clipper
system which is expected to dive through the area Thursday night
into Friday. Any lingering flurries or light snow showers should
dissipate by late Thursday morning as the upper trough axis pushes
east of the Appalachians. Temperatures should remain cool on
Thursday, with highs in most locations expected in the 30s. With
little in the way of return flow, clouds are likely to stick around
through much of the day on Thursday, with mostly cloudy skies
expected.

Thursday night into Friday, another clipper system will drop across
the Ohio Valley within the broader NW flow pattern. A NW-SE oriented
band of precipitation is expected to develop on the cold side of the
effective sfc warm front, with isentropic upglide and broad rising
motion downstream of an upper-level shortwave serving as sources of
lift. As with the mid-week system, moisture with this system will be
somewhat limited as SW low-level flow limits access to Gulf moisture
sources. In spite of this, there will likely be a stripe of light to
moderate precipitation which results in accumulating snowfall across
portions of the Ohio Valley. Exactly where that occurs is still
uncertain, and the cutoff between areas which receive significant
accumulations and areas which see no snow is expected to be fairly
sharp. The most consistent signal for accumulating snowfall has been
along and northeast of a line extending from Jasper to Louisville to
Richmond, in other words, mainly across southern IN and northern KY.
While most likely snowfall amounts within this band of precipitation
are generally in the advisory-level range, this amount of snow could
lead to detrimental impacts to travel conditions during the first
half of the day on Friday, so it bears watching over the next few
days.

Later in the day on Friday, precipitation should clear the region as
the system moves off to the east of the area. Surface high pressure
will begin to nose in from the northwest Friday night; however, the
onset of the heart of this cP air mass continues to look to be
slower to arrive, with temperatures gradually easing downward over
the weekend. Another system may try to swing through the region
Saturday into Saturday night before upper troughing and sfc high
pressure finally settles into the region on Sunday; however, a
consistent picture is yet to be depicted in medium-range guidance,
and confidence is still low. If we were to see precipitation during
this time period, mixed precipitation types would be possible, with
better chances of wintry weather to the north and greater likelihood
of rain to the south.

Saturday night into Sunday, high pressure is expected to sink into
the region, with temperatures tumbling into the 20s and low 30s for
the day on Sunday. Low temperatures Sunday night are currently
expected to be in the upper single digits and low-to-mid teens, some
of the coldest air of the season thus far. During this time period,
dry weather is more likely, though as mentioned above, forecast
confidence is pretty modest at this lead time.

&&

.AVIATION /06Z TAFS THROUGH 12Z THURSDAY/...
Issued at 108 AM EST Wed Dec 10 2025

Ahead of an approaching cold front, tight pressure gradients will
cause gusty winds and LLWS. Winds will continue slowly veering from
the southwest towards the northwest through the period. Gusts from
25-35 knots are expected over southern Indiana and central Kentucky.
Rain chances will begin increasing over the next few hours with rain
expected to work southeast through the region. The heaviest showers
are expected to end by this afternoon with low chances of
precipitation remaining into the night. The lighter activity during
the later afternoon and evening will likely change over to a light
snow or a mix.

&&

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

&&

$$

UPDATE...EBW
SHORT TERM...CSG
LONG TERM...CSG
AVIATION...KDW