838
FXUS63 KLMK 250212
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
912 PM EST Sun Nov 24 2024

.KEY MESSAGES...

*  Scattered rain showers expected Monday afternoon and evening with
   the passage of a cold front. Mild and breezy Monday -
   temperatures in the 60s dropping back into the 30s by Tuesday
   morning.

*  Another round of rain arrives later in the day on Wednesday.

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

&&

.UPDATE...
Issued at 912 PM EST Sun Nov 24 2024

Clouds around 3-4k` have been blossoming over Missouri this evening
on the nose of a 925-850mb jet. These clouds will spread east
tonight and give us mostly cloudy skies after midnight, and a stray
sprinkle can`t be ruled out towards dawn especially in southern
Indiana where the cloud bearing layer will be thickest.

Breezes will come in from the southwest ahead of low pressure
traveling from Kansas City to Chicago. As a result, overnight low
temperatures will likely occur around 1am EST/midnight CST and then
slowly rise 3-5 degrees by sunrise.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 330 PM EST Sun Nov 24 2024

1001 mb sfc low is analyzed over KS this afternoon, with
strengthening SW low-level flow over the Ozarks and Mid-MS Valley.
In the upper levels, low pressure is spinning over Saskatchewan
while a shortwave trough traverses MT/WY. Downstream, low-amplitude
ridging is building eastward over the Upper Midwest and Great Lakes.
Locally, skies are partly to mostly sunny with only some thin cirrus
overhead. Southerly winds have begun to respond to a tightening
pressure gradient ahead of the Plains low. These factors have
allowed temperatures to warm into the upper 50s to mid 60s.

A 40-45 kt SW LLJ overspreads the Lower OH Valley tonight as sfc low
pressure lifts northeast toward Chicago. We will see some low-level
moisture return, though the atmosphere will just remain too dry for
any rain overnight. Temperatures should initially be able to drop a
decent amount this evening with relatively clear skies and the
development of the nocturnal inversion. However, temperatures will
stabilize and then rise early Monday morning. Clouds will quickly
increase from NW to SE during the pre-dawn hours. Lows will range
from the low/mid 40s in the Bluegrass to the upper 40s/near 50 along
and west of the I-65 corridor.

Tomorrow, the lead upper level shortwave trough swings over the
Upper and Mid-MS Valley as sfc low pressure develops NE over
Southern Lower MI. We`ll remain relatively dry during the morning
hours. Modest moisture advection continues ahead of the approaching
cold front, but moisture will remain fairly shallow. We will likely
see some isolated light rain.

A band of scattered light showers is expected to push east across
the area during the afternoon and evening hours. A narrow plume of
deeper moisture will accompany the cold front as it sweeps through
the region. Fcst soundings show a stable environment, with warm air
in the mid-levels. Thunder is unlikely at only a 5-10% chance.
Rainfall totals are likely to be in the 0.10-0.25 inch range through
Monday night.

Monday will be mild and breezy. High temperatures will be in the low
to mid 60s. Winds from the southwest will gust to 20-25 mph. Light
shower activity will linger into Monday night, mainly east of I-65.
Rain tapers off in the Bluegrass Region early Tuesday morning. Much
cooler, drier air streams into the region behind the cold front.
Skies should start to clear west of I-65 prior to daybreak Tue. It
will be a chilly morning, with lows ranging through the 30s.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Issued at 330 PM EST Sun Nov 24 2024

Tuesday is expected to be a decent dry day with zonal flow overhead
and high pressure building in at the surface. Skies become mostly
sunny, but CAA will limit highs to the mid 40s to low 50s. During
the afternoon and evening hours, the center of a surface low is
expected to pass east through northern parts of the CWA,
resulting in light return flow into the Lower Ohio Valley late
Tuesday night, and by late Tuesday night, mid and upper level
cloud cover from low pressure over the Southern Plains will be
carried into the region by zonal flow.

By Wednesday morning, winds will be out of the south, leading to
increasing low level moisture. Precipitable water values around
0.50" in the morning will increase to around 1" by the evening
hours, and while this is happening, a surface low will get pushed
from near Interstate 35 on the Oklahoma/Texas line east towards the
CWA into an area with enhanced forcing from the right entrance
region of an upper jet (sitting west to east from the southern Great
Lakes and east). This would begin to increase rain chances over
southern Indiana and central Kentucky later in the day.

Model agreement is pretty good overall, but the location of where
this surface low ends up differs. The Euro takes the low farther
north, through the center of the CWA, and the GFS passes it farther
south, through the Tennessee Valley. This will influence rain
totals, but either way, this will be an all rain event without
thunder. Model soundings are very stable.

The low pressure track will also influence the cold front trailing
behind the low. The GFS makes the front west to east oriented which
could add to higher rainfall amounts over fewer people in the CWA
(currently southern Kentucky) as the duration of rainfall would be a
little longer, but over a narrower path. The Euro`s northern
placement of the low would lead to a more northeast to southwest
oriented front which would produce a more uniform rain total across
the CWA. The exact placement should come into better focus in the
coming days at we near the event.

Rain will likely come to an end by early Thursday night, and behind
the front, CAA ahead of a a large surface high will keep high
temperatures suppressed to the low 30s to low 40s through the
weekend.

&&

.AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 632 PM EST Sun Nov 24 2024

Ahead of a Plains storm system tonight a low level jet will stretch
from northeast Texas to southern Ohio, leading to LLWS in the TAFs
for the overnight. Moisture will stream into the region with this
brisk southwest flow, bringing in VFR ceilings for the early morning
hours.

Flying conditions will deteriorate tomorrow as low pressure
traveling from ORD to MBS drags its trailing cold front to around I-
65 by 00Z. Ceilings will lower, possibly to IFR by mid-late
afternoon, and rain chances will increase.

&&

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

&&

$$

UPDATE...13
SHORT TERM...EBW
LONG TERM...KDW
AVIATION...13