078
FXUS63 KLMK 241820
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
220 PM EDT Fri May 24 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Dense Fog Advisory in effect until 10AM.

*   Stormy pattern with risks of strong to severe storms and
    localized flooding issues will continue into Monday.

*   The greatest threat for severe weather will likely come Sunday
    afternoon into Sunday night ahead of a cold front. Severe storms
    will be capable of producing damaging winds, large hail, and
    tornadoes.

&&

.UPDATE...
Issued at 1251 PM EDT Fri May 24 2024

While many over southern Indiana and central Kentucky have seen
sunshine today, there are some, including the Louisville area, that
have held on to a layer of stratus. It won`t be long before this
layer should fully dissipate, but convection to the west is blowing
more low to mid level clouds east into and across central Kentucky.
This morning has seen limited warming under those areas that have
held onto the stratus. They are just now reaching around and into
the low 70s while areas to the west are in the mid to upper 70s.
Should be a fairly dry day until more showers and thunderstorms
begin to move in later this afternoon and evening. Updates to
temperatures and sky cover have been made to today`s forecast.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 340 AM EDT Fri May 24 2024

Now Through Mid-Morning...

The last of the rain has exited the Bluegrass and skies have
cleared. Weak ridging aloft has allowed for skies to remain clear
and winds light. Due to clear skies, light winds, and recent precip,
low stratus and fog has developed over central Kentucky. This fog is
slowly spreading north and south. An SPS was issued earlier for
patchy dense fog over these regions. With the current satellite and
observation trends, a Dense Fog Advisory is now being issued over
these same areas. With sunrise, fog will begin to thin.

Mid-Morning Through Evening...

Once fog clears out of the region, skies will remain mostly clear
with scattered diurnal Cu development in the afternoon. Today`s
temperatures will be a few degrees warmer than Thursday in the low-
mid 80s. In the late afternoon, a 35-40kt LLJ will move into the
region from the SW bringing additional moisture advection and will
raise dew points into the mid-upper 60s. Scattered showers and
storms will likely develop and move NE over the region. These storms
will be similar to the previous days, unorganized multicells capable
of heavy downpours, gusty to damaging winds and up to 1 inch hail.

Given multiple days of rain, localized flash flooding is possible.

Friday Night into Saturday Morning...

A stacked low pressure system currently over the northern Plains
will move northeast into southern Canada and the associated cold
front will propagate into the region. This front will likely stall
along the Ohio River. A line of showers and storms will outpace the
best forcing along the front and weaken as it approaches the region.
This weakening line is expected to move through in the early morning
hours. Given weak forcing and a stable airmass overnight, these
storms may only produce small hail and heavy rain. Due to these
reasons, SPC has trimmed the slight out of the CWA.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 340 AM EDT Fri May 24 2024

Saturday is a somewhat tricky forecast as we`ll have a slowing or
stalling cold front in a modestly unstable and weakly sheared
environment. With the lack of shear and a fairly modest deep
moisture supply, expect scattered but disorganized showers and
storms, mainly during the heat of the afternoon.  Coverage will be
the lightest over southern Indiana, where we`ll just carry a 20 POP,
ranging to near 50 percent near the I-75 corridor in KY.

After a dry Sat night, we`ll have a warm front lifting through the
region Sunday morning with a healthy low-level jet to pump PWATs
back up toward 1.7 inches by late in the day. Strong shear will
develop through the day with a 45 kt southwesterly LLJ at 850mb and
westerly H5 winds around 55 kt.

Multiple rounds of storms are possible Sunday into Sunday night, but
the most widespread activity will likely arrive late Sunday
afternoon into Sunday evening as a cold front pushes in from the
west. While there are some factors that could hamper the
impactfulness of this event (i.e., destabilization between waves of
showers/storms, strength of capping inversion, etc), the overall
synoptic environment is one that would support organized convection
capable of damaging winds, large hail, and tornadoes. If everything
comes together just right, this could be a potentially significant
event.

Scattered shower and storm chances will persist on Memorial Day as
we remain under cyclonic flow aloft. Expect this activity to be non-
severe as instability will be lacking, and less of a flash flood
threat given the loss of deep moisture. Drier and slightly cooler NW
flow regime will follow during the middle portion of next week.
Can`t rule out a stray shower or storm in that pattern but chances
will be limited to 20% or less.

&&

.AVIATION /18Z TAFS THROUGH 00Z SUNDAY/...
Issued at 219 PM EDT Fri May 24 2024

Many across southern Indiana and central Kentucky will remain dry
over the next few hours, but as we head later into the afternoon and
evening hours showers and thunderstorms will become more likely at
area TAF sites. This could cause reduced visibilities and
variability in wind during periods of heavy rainfall, but long
periods of reduced visibilities aren`t expected. Currently, model
soundings aren`t handling cloud cover very well. Convection over
western Kentucky and Tennessee are blanketing the region under all
levels of cloud cover. This has been making the ceiling forecast
difficult, but cloud cover is expected to last through the overnight
hours which will help reduce the chances of widespread fog tomorrow
morning.

&&

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

&&

$$

UPDATE...KDW
SHORT TERM...SRM
LONG TERM...RAS
AVIATION...KDW