000
FXUS63 KLMK 041150
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
650 AM EST Mon Dec 4 2023

...Updated Aviation Discussion...

.Short Term...(Today and tonight)
Issued at 303 AM EST Mon Dec 4 2023

================================================================
Key Messages

- Light rain this morning

- Light rain with possible snow flake or two late tonight over
  southern Indiana/northern Kentucky

================================================================

A low pressure system currently over Missouri will continue east-
southeast towards central Kentucky. This is slightly farther south
than yesterday`s forecast. The impacts remain about the same with
light rain ahead and north of the circulation. Model soundings show
a small dry layer near the surface, so this will likely impact
totals as well. Given the orientation and short dwell time, totals
will be limited on the southern extent of the rain on the leading
edge of the low. On the northern side, where rain begins to wrap
around the low and dwell time is a little longer, expect higher
totals. On the northern and southern extremes of the CWA, these
areas may only see a trace or hundredth of an inch while areas along
the heaviest axis could see around 0.1 to 0.4" or so. Precipitation
will dissipate as the system moves east over the CWA, resulting in
higher totals to the west and tapering off to the southeast. Winds
will remain fairly light, around 5-8 mph, most of the day, but a few
peak gusts could reach near 15 mph is southern Kentucky. Winds
however will remain variable as they wrap around the low cutting
through Kentucky. Most of the rain will come to an end early in the
afternoon. Skies are expected to scatter from the north to south
during the afternoon and evening hours. Highs are expected to reach
from the upper 40s to low 50s for most to the mid 50s in south
central Kentucky.

Tonight will begin under scattered (in the north) to broken (in the
south) skies before a clipper system diving to the southeast across
central Illinois begins impacting southern Indiana after midnight
into the predawn hours. This system from Saskatchewan will bring its
own moisture, and by the time it arrives, there won`t be much left.
Model soundings show a fairly deep layer of saturation with no warm
nose, so with temperatures in the low 30s across the northern half
of the CWA, there will likely be some across the northern parts of
our area that will see snow flurries mixed in with the light rain
moving into the area. By sunrise, our northwestern communities could
see around a hundredth, so again don`t expect too much with this
system.

.Long Term...(Tuesday through Sunday)
Issued at 258 AM EST Mon Dec 4 2023

====================================================================
Key Message:

- Impactful weather this weekend with possible heavy rain and
20% chance of thunder

====================================================================

A weak clipper will slide from eastern Iowa to eastern Kentucky
Tuesday. We can expect light rain showers with this system, though
moisture will not be particularly plentiful, especially south of the
center of the low`s track. Additional light rain showers will be
possible Tuesday night ahead of an upper trough axis pivoting
through. Rainfall amounts through Tuesday night should be on the
order of a tenth of an inch...with even the 95th percentile of LREF
guidance only up to 0.15". A few snowflakes may mix in late Tuesday
night north of I-64 as temperatures drop into the lower and middle
30s.

Though the clipper and upper wave will be to our east by Wednesday,
lingering low level moisture will remain over the region, and 1000-
850mb streamlines with RH > 70% in the layer coming down the length
of Lake Michigan into the Ohio Valley will further support a low
cloud deck Wednesday morning before high pressure building in from
the west begins to break up the clouds in the afternoon. The cloud
layer will not be particularly deep and we`ll be behind the
aforementioned upper trough axis, so little if any precipitation is
expected other than perhaps a few sprinkles or isolated flurries
late Tuesday night into early Wednesday morning. High temperatures
Wednesday will only be in the low to mid 40s...five to ten degrees
below normal.

Dry weather is in store Wednesday afternoon through Friday as high
pressure crosses the southeast United States. Temperatures will
moderate well into the 50s on Thursday and to around 60 Friday ahead
of the weekend system.

Low pressure crossing from Ontario to Hudson Bay will drag a cold
front towards the Ohio Valley Friday night-Saturday, with frontal
passage likely sometime Saturday night. There will be plenty of
moisture available with 1"+ precipitable water values above the 90th
climatological percentile, and with a strong low level jet from
Texas to New York showers will be widespread along and ahead of the
incoming front. Instability progs, upper jet structure, CSU-MLP, and
CIPS analogs still support the best chances of severe storms to our
southwest, starting in the Arklatex region and spreading eastward,
just to our south. Still, can`t rule out some embedded thunder this
far north.

Post-frontal showers will continue into Sunday. Total QPF from
Friday night into Sunday right now is in the 1.50-2" range, which
would put a significant dent in the current drought conditions.

After highs Saturday in the low-mid 60s, Sunday will be a damp,
blustery day with a stiff breeze and temperatures only reaching the
middle and upper 40s.

&&

.Aviation...(12Z TAF Issuance)
Issued at 649 AM EST Mon Dec 4 2023

We are starting to see a little low pressure system move in from the
west. The latest data has been a little more optimistic as the
system is expected to weaken as it move east. Rain showers with the
system are expected to be light, but ceilings at HNB will will
likely bounce between MVFR and VFR. Not expecting many visibilities
issues. Again, HNB could drop into MVFR levels for a very short
time. Winds will be light and variable as the low moves through.
Ceiling will try to scatter out from the north to south later in the
afternoon.

&&

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

$$

Short Term...KDW
Long Term...13
Aviation...KDW