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000
FXUS63 KLMK 100736
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
336 AM EDT Wed Apr 10 2024

.KEY MESSAGES...

*  Continued rounds of rainfall expected through Friday. Brief
   ponding or flooding of low-lying areas possible with the heaviest
   rain.

*  A few strong to severe storms possible late tonight into
   Thursday. Main threat is locally damaging wind gusts, with a low-
   end tornado potential on Thursday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 336 AM EDT Wed Apr 10 2024

Southern stream upper low is over west Texas and continuing to make
slow eastward progress, with a slow-moving sfc cold front roughly
along I-44 in Missouri and I-70 in Illinois and western Indiana.
Intermittent waves of light to moderate rain showers continue to
pinwheel into the Tennessee Valley and northward into Kentucky as
disturbances eject out of the upper low, and overall we expect this
pattern to persist today and tonight.

Confidence is high that most if not all locations will receive rain
at some point today and tonight, but the timing is what remains
uncertain. Also in question is the potential impact of any of this
precip, mainly in terms of potential severe wx.

One wave of light precip is now roughly up to the Western Kentucky
Parkway, and will continue to lift north through late morning, at
which point it will hang up just north of our Indiana counties. Will
keep mention of isolated embedded thunder but that may be generous
given the lack of lightning that we have been seeing overnight. QPF
with this wave may be up to a quarter inch but will average closer
to a tenth.

After a break this afternoon, we will start to see chances ramp up
before sunset west of I-65, as the sfc low to our SW deepens and the
front to our NW edges closer. Best chances will be late tonight as
an inverted trof or warm front pinwheels north into Kentucky, and
the low-level jet cranks up. Instability remains unimpressive as the
thermal profiles are moist adiabatic through a deep layer, but with
winds pushing 50 kt just 1km off the deck, it wouldn`t take much to
mix down a stray near-severe gust. So expect some gusty showers or a
few T-storms across south-central Kentucky after midnight tonight,
in line with the Day 1 Marginal from SPC. The threat for flooding
isn`t as great as previously advertised, as the higher QPF is
increasingly focused to our north and west, more toward the Wabash
Valley. Still can`t rule out some ponding or nuisance flooding in
some low-lying areas with the heaviest showers.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 336 AM EDT Wed Apr 10 2024

On Thursday morning, a low pressure system will begin cutting
northeast through southern Indiana. The global models have shifted
their track of this low pressure system farther to the southeast,
closer to where the NAM was showing yesterday. Now that some of the
CAMs have this period in focus, they agree with the southern track.

As we begin the morning around 12z, model soundings appear fairly
stable with a max of 200-300 J/kg of MLCAPE in our area, but as the
morning wears on, an area of 600-700 J/kg of MLCAPE will become
possible. Deep layer shear and low level shear profiles are meager.

SPC currently has a Slight risk stretching from the Kentucky
Bluegrass to the northeast. They are factoring in added forcing from
the region sitting under the left exit region of a mid-level jet and
a dry slot, possibly adding some sunshine and helping with
instability. They acknowledge the timing window for severe weather
is limited.

Given current data, believe scattered showers will see some
development into thunderstorms later in the morning, but model
soundings don`t support much of a tornado threat. Gusty winds and
some hail will be possible, but believe this would be sub-severe.
Believe the greater threat for severe weather is farther east and
north, in eastern Kentucky and Ohio.

As the front attached to the low passes during the afternoon and
evening hours, stable deep layer moisture is expected to bring
widespread showers through the CWA. Most of this activity will come
to an end early Thursday night. The front will kill warm air
advection as cold air advection takes its spot and drops Thursday`s
highs in the mid 60s to low 70s down into the mid to upper 40s early
Friday morning.

On Friday, wrap around moisture will bring an additional chance for
some light precipitation. This will mainly be over southeast Indiana
and north and east Kentucky. Surface high pressure, centered over
the western Gulf Coast, will expand its influence into the Lower
Ohio Valley as a collapsing upper ridge pushes east into the region.
This will bring clearing skies from the west into central Kentucky
and southern Indiana. Temperatures recover from the 60s on Friday to
the upper 70s to low 80s by Monday. Precipitation chance begin
increasing again early next week ahead of the next system.

&&

.AVIATION /06Z TAFS THROUGH 12Z THURSDAY/...
Issued at 128 AM EDT Wed Apr 10 2024

MVFR is spreading back in from the south, a bit behind schedule but
BWG did drop within the past hour. Look for MVFR cigs and a few
showers into SDF and LEX around 09Z, then quickly dropping into IFR
for most of the morning as another wave of rain moves through.

Some recovery in ceilings is expected after 18Z, with SDF and LEX
lifting to MVFR but staying below 2000 feet, and BWG going VFR if
only just barely.  SE winds will come around closer to due south,
with gusts just short of 20 kt in BWG.

Look for MVFR cigs again after sunset with winds backing to ESE as
the sfc low deepens. Forecast confidence is lower in LEX where there
is disagreement on staying in the warm sector.

&&

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

&&

$$

SHORT TERM...RAS
LONG TERM...KDW
AVIATION...RAS