160
FXUS63 KLMK 250837
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
337 AM EST Mon Nov 25 2024

.KEY MESSAGES...

*  Scattered rain showers are expected this afternoon and evening
   with the passage of a cold front.  Highs will be in the 60s today
   with lows tonight dipping back into the lower-mid 30s.

*  Another round of rain arrives later in the day on Wednesday. Rain
   chances peak Wednesday night into early Thursday morning.

*  Unpleasant weather for Thanksgiving Day, with cold light rain,
   and brisk northwest winds of 10-15 mph with gusts to 20 mph.

*  Much colder temperatures possible for the weekend, with daily
   highs mostly in the 30s for Friday - Sunday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 336 AM EST Mon Nov 25 2024

Early morning satellite imagery shows mostly cloudy across western
and central KY, though eastern KY remained clear.  Temperatures
across the region ranged from lower 30s in the clear skies over
eastern KY to the lower-mid 50s in between the I-65/I-75 corridor.
Out across western KY temperatures were in the lower 60s.  Through
sunrise, no significant weather is expected.  Given the warm
advection pattern temps will slowly continue to rise toward sunrise.

For today, a mid level trough axis over the northern Plains will
push eastward into the Great Lakes.  Associated surface low will be
near Chicago this morning and then move eastward across lower
Michigan through the day while a southwestward extending cold front
moves toward IN/KY.  For the morning hours, we will likely remain
dry as the atmospheric column continues to moisten.  We may see some
light sprinkles/drizzle develop toward lunch time west of I-65.  As
the surface cold front comes into the region this afternoon, we`ll
see a plume of moisture pool in front the front.  Forcing along the
front should promote a band of rain showers in advance of this
frontal boundary.  Model forecast soundings across the region
continue to show little in the way of instability.  There may be a
little bit of elevated instability right along the front which could
promote a few rumbles of thunder as the boundary passes through.  It
will be breezy ahead of the front as the pressure gradient
increases.  Southwest winds of 10-15 mph with gusts of 20-25 mph
will be possible.  Highs this afternoon will top out in the 60-65
degree range.

As we move into the evening and overnight hours, the cold front
should cross the I-65 corridor around 26/00Z and then exit the LMK
CWA by 26/03-04Z.  Rain will quickly diminish behind the front as
drier/colder air pushes into the region.  Some partial clearing of
skies will be possible in areas west of I-65 toward sunrise Tuesday.
Given the expected cold advection, temperatures will tumble
overnight with lows dropping into the low-mid 30s.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 336 AM EST Mon Nov 25 2024

===== Tuesday - Tuesday Night =====

Tuesday will be a very nice day for our area, thanks to zonal flow
aloft and sfc high pressure passing through. Sunny skycover is
expected for the morning and afternoon, though northwest sfc flow
will promote a CAA pattern, helping to keep temps in the upper 40s
and lower 50s.

By Tuesday evening, upper level cloud cover will begin to increase
across the northern half of the forecast area as an upper jet streak
extends over Illinois and Indiana. To our west, an upper shortwave
will be swinging down from the Pacific Northwest toward the Rockies,
which will eventually end up being our next system later in the
week. Conditions will remain dry Tuesday night with sfc high
pressure directly overhead, resulting in nearly calm winds and temps
cooling into the 30s region-wide.


===== Wednesday - Thursday =====

Dry weather continues for Wednesday morning as the sfc high slides
off to our east. When doing so, it`ll set us up to get into a
southerly flow regime, with WAA and moisture transport increasing
later in the morning as the aforementioned sfc low pivots across the
central US. Rain chances will arrive by the afternoon hours, though
relatively dry air below 700mb will likely lead to some virga at
first, but our column should become fully saturated by the early
evening. Rain chances considerably ramp up for Wednesday evening and
night as vorticity increases with the arrival of the upper
shortwave.

While overall guidance is in good agreement on seeing rain Wednesday
night and for Thanksgiving, there continues to be model spread on
the track of the associated sfc low for Wednesday night. The track
will determine where the moisture plume will set up, which leads to
differing QPF amounts. The ECMWF continues to suggest the sfc low
track to pass right over south-central Kentucky, bringing better
chances for PWATs over 1.0 inch as far north as the Ohio River. The
Canadian is a more southern track, with the sfc low track somewhere
near the Tennessee/Alabama border, and the greatest low-level
jetting and moisture transport axis setting up across northern
Alabama and Georgia. The GFS is in between the Euro and Canadian,
with a sfc low track across middle Tennessee.

Rain chances will peak for the overnight hours between Wednesday and
Thursday. Soundings show us stable, so no thunder will be expected
with this wave. Thursday morning will feature decreasing rain
chances as the sfc low pushes east, though at least isolated light
rain remains possible through much of the day. The sfc pressure
gradient will be rather tight, resulting in breezy NW winds
throughout the day. With temps only in the 40s, and with isolated
cold rain, breezy northwest winds of 10-15 mph with gusts 20-25 mph
will make it quite unpleasant to be outdoors. Apparent temps will
likely be in the 30s.

Drier air will finally begin to filter in by Thursday night, which
will allow for rain chances to taper off from west to east after
sunset. CAA will be quite strong for Thursday give NW flow, which
will allow for temps to drop into the 20s overnight. Cloud cover
will slowly clear from the west too, but we won`t entirely clear out
before sunrise on Friday.


===== Friday - Weekend =====

Elongated Canadian high pressure will be stretching across the
central part of the country on Friday. This will keep NW flow and
CAA for us, resulting in temps well below normals for Friday and
into the weekend. Cloud cover will gradually diminish during the day
on Friday, and temps will likely remain in the 30s. The coldest
airmass of the season comes on Saturday morning, with potential for
low temperatures in the upper teens outside of our urban islands. We
could see a weak low level shortwave quickly pass through the area
for Saturday. With temps expected to be below freezing, we could see
a round of light snow beginning Saturday afternoon and lasting
through the night. Confidence remains very low on this at this time.

Canadian high pressure will continue to build to our west for Sunday
and into early next week, which will help keep the cold temps in
place for the start of next week. We could end up seeing low temps
solidly in the teens, even for the urban areas for Monday and
Tuesday mornings. We`ll get into the finer details in the coming
days, but for now it is certainly worth keeping an eye on.

&&

.AVIATION /06Z TAFS THROUGH 12Z TUESDAY/...
Issued at 1219 AM EST Mon Nov 25 2024

Overnight, main forecast concern will be LLWS as the nocturnal low-
level jet will stretch northeastward from TX to OH.  Moisture will
continue to stream into the region with VFR cigs giving way to MVFR
cigs by sunrise.  For the daytime hours, cigs will continue to lower
through the day as a cold front approaches the region from the west.
Cigs will likely lower to IFR in the afternoon with scattered rain
showers across the region.  Surface cold front looks to cross the I-
65 corridor by 26/00Z and then through the I-75 corridor by 26/02-
03Z.

&&

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

&&

$$

SHORT TERM...MJ
LONG TERM....CJP
AVIATION.....MJ