Area Forecast Discussion
Issued by NWS Louisville, KY

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FXUS63 KLMK 240718
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
318 AM EDT Sun Mar 24 2024

.KEY MESSAGES...

* Impactful storm system Monday through Tuesday with gusty winds,
  widespread rainfall, and a few storms possible.

* Gusts of 30 to 40 mph possible for some late Monday night into
  Tuesday. Higher gusts posssible, but confidence is low for now.

* The mild, dry, and gusty winds on Monday could lead to increased
  fire danger.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 317 AM EDT Sun Mar 24 2024

A dry day is in store for our Sunday due to mid-level ridging
overhead and sfc high pressure to our north. This sfc high will
promote a cool easterly flow for our area. Upper clouds will begin
to increase by this afternoon, which will be in response to a low
pressure system spinning up across eastern Colorado. Did knock temps
down a few degrees from NBM to align with the median of all
available model guidance, as the easterly flow and increasing cloud
cover should result in temps underachieving today. Highs in the mid
to upper 50s seem likely, possibly some low 60s across our south
too.

For tonight, we remain dry as the sfc high departs off to our
northeast, and we await the arrival of our next system. An upper
trough to our west will pivot across the southwestern US tonight,
pushing the aforementioned sfc low to the east-northeast. With the
sfc high departing, we`ll begin to feel the influence of this sfc
low as our winds turn to the southeast and promote a WAA regime.
It`ll be a mild night due to these winds and the increased cloud
cover. Overnight lows will be in the 40s, with the warmer temps
expected west of I-65 where southerly flow will be stronger.
Speaking to that, a notable LLJ will be to our west, and the eastern
periphery of it will be working into western Kentucky and southern
Indiana tonight. Winds could become quite breezy west of I-65
tonight.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 317 AM EDT Sun Mar 24 2024

Monday - Tuesday Night...

Pretty active stretch of weather expected through the early week
time frame as a strong low pressure system moves from the central
Plains through the western Great Lakes. A tight pressure gradient
looks to set up between the ~990 mb surface low and high pressure
centered over far eastern Canada. Meanwhile, upper ridging aloft
centered up the Atlantic Coast will try to hold over our area, but
will eventually give way to the ejecting trough out of the western
CONUS. This will result in a largely dry, mild, and gusty Monday
before widespread showers and a few t-storms overspread the area
Monday night. Lingering showers and a few storms hang around for
Tuesday into Tuesday night ahead of the trailing cold front.

The jet dynamics with this system are quite impressive as models
continue to suggest a very intense low level jet (70-75 knots)
responding beneath the exit region of a 140 knot upper jet. This
will provide large scale forcing along with excellent moisture
transport ahead of the upper trough axis and trailing surface cold
front. The good news is that it appears any surface or near-surface
based instability will be hard to come by thanks to a strong low
level inversion, and late surface moisture recovery. In fact, dew
points on Monday afternoon will only be in the 30s before Monday
night advection eventually brings Td`s up into the low 50s. Given
the degree of forcing expected combined with some meager elevated
instability, do expect there could be some isolated thunder with any
thin line convection embedded in the larger stratiform rain shield,
so will continue to mention iso T. Not overly concerned about the
severe threat, given the expected stable layer, however there is
always some concern when you have a low level jet that strong
combined with stronger showers or a storm that could realize some of
those winds down to the surface. A widespread threat is not
expected, but perhaps a few isolated stronger gusts could be
possible with any more robust convection Tuesday morning.

There is also concern for the gradient wind threat alone from later
Monday afternoon through Monday night given the low level wind
field. Although the peak of the LLJ core doesn`t arrive over our
area until overnight, and soundings show a pretty stout inversion
over our area. We become a little less stable toward sunrise on
Tuesday as the main line of convection from upstream approaches, and
this appears to be our best shot at some stronger (possibly Wind
Advisory criteria) gusts. Not confident enough at this time to go
with any headlines given the expected stability, but certainly
something to be mindful of over the next few forecasts. Given how
dry the low level might be given how dry we get Monday afternoon,
some of our best gusts may come on the leading edge of precipitation
onset as the column saturates later Monday night.

The dry slot of this system overspreads our area on Tuesday, cutting
off the widespread precipitation. However, this will allow an
opportunity to destabilize a bit into the afternoon and evening
before the cold front finally pushes through. Models have been
consistently showing some redevelopment, however not sure how robust
this activity will be able to get, and it appears the best LLJ core
will be off to the east by then. May have to keep an eye on Tuesday
afternoon/evening as a sneaky/sleeper secondary threat of some gusty
winds or even a strong storm or two, but confidence will remain low
for now. Overall, rainfall totals look manageable in the .50" to
.75" range for most.

Monday highs should peak in the upper 60s to around 70, but this
could also be a setup to overachieve in. May go a bit higher than
guidance here. Monday night looks mild as well with lows in the 50s.
Tuesday also looks mild before the cold front is able to swing
through with highs in the mid and upper 60s. However, temps will be
in the 30s to low 40s by dawn on Wednesday behind the strong cold
front.

Wednesday - Saturday...

Canadian high pressure at the surface and unremarkable zonal flow
aloft take hold for the remainder of the week into the first part of
the weekend. Looking for a dry forecast through the rest of the work
week, with perhaps some rain chance returning for Friday night or
Saturday. Temperatures will be cooler in the 50s for Wed/Thu, before
recovering back into the 60s and possibly lower 70s (SW CWA) for
Friday/Saturday.

&&

.AVIATION /06Z TAFS THROUGH 12Z MONDAY/...
Issued at 148 AM EDT Sun Mar 24 2024

VFR conditions will continue throughout the entire period. We`ll
have a mix of FEW and SCT cirrus, but expect a high level ceiling to
develop by this afternoon and evening. Winds will be the main focus
this TAF package. NE winds this morning will gradually become more
ESE by tonight. Wind speeds will mainly remain under 10 kts through
the period.

&&

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

&&

$$

SHORT TERM...CJP
LONG TERM...BJS
AVIATION...CJP


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