258
FXUS63 KLMK 162356
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
756 PM EDT Tue Jul 16 2024

.KEY MESSAGES...

*   Storm chances increase tonight into tomorrow as a frontal
    boundary sinks into the region. Flash flooding possible in areas
    that see repeated storms. Isolated strong storms with gusty
    winds possible as well.

*   Cooler temps in the 80s for Thursday into the end of the week.

*   Storm chances return early next week.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 301 PM EDT Tue Jul 16 2024

Plenty of convective cloud debris has hung around today, from both
the morning line of showers and storms, as well as from the
stationary cluster of convection over Illinois today. This cloud
cover has help limit our sfc heating, with most obs in the upper 80s
so far this morning. Less cloud cover over the Bluegrass has allowed
that area to warm into the 90s. Besides the Bluegrass region, heat
indices have not reached the triple digits, so the Heat Advisory
will be let go with this forecast package. It`ll still be very warm
and muggy this afternoon, specailly in the Bluegrass.

For the rest of this afternoon, a few isolated pop-up showers or
storms will be possible in an unstable airmass. The latest HRRR was
suggesting a few isolated cells over in the Bluegrass later this
afternoon, which is the area with the best heating today, so it
seems possible. Otherwise, the higher precip chances will come
tonight.

===== Tonight =====

A very slow moving frontal boundary will still be extending from
central Missouri to central Indiana tonight, but a very muggy
airmass ahead (south) of the front will support shower and storm
development overnight. While run-to-run consistency has been a
struggle, there is good agreement on our area having very high
PWATs, with over a 60-70% probability of exceeding 2 inches. While
QPF has come down slightly in today`s runs, the environment
overnight will be favorable for heavy rainfall, along with some
possible training as showers and storms line up and move parallel to
the frontal boundary to our north. The flood watch will remain as is
for now, especially given the concern for any nighttime flooding
from heavy rainers. As for the storm potential, most model soundings
depict elevated instability, with stable air in the lowest levels.
Not too concerned for severe risk tonight, but perhaps we could have
a few gusty winds with any stronger core that develops and results
in a water-logged downburst. The main timing for overnight activity
will be after midnight and before 12z tomorrow.


===== Wednesday =====

We`ll remain in the same type of airmass tomorrow, as the front will
still be to our north. PWATs will remain quite high, with another
round of isolated to scattered showers and storms for the day as we
become unstable in the afternoon. While we`ll have plenty of
instability for storms to work with, we will be lacking shear,
leaving most storms to be messy and unorganized. Soundings show a
bit more saturation in the columns, resulting in lower DCAPE values.
Will mostly expect garden variety storms tomorrow, but a few strong
storms could pack a punch of wind. Otherwise, overall severe threat
is low for tomorrow. Eventually the front will begin to make its way
through our area late in the day, but it will only make it to around
the Ohio River towards the end of the short term period.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 301 PM EDT Tue Jul 16 2024

By Wednesday night, the cold front should begin entering the
Commonwealth, draped roughly parallel along the OH River, as
isolated to scattered showers and thunderstorms out ahead of
the front begin to wane across the CWA with the setting sun. Cold
front is progged to be exiting our area by sunrise Thursday morning,
allowing for surface high pressure to build in across the region.
This will bring some relief to the recent sultry conditions, as
afternoon max temperatures reach into the low 80s Thursday while
increasing a couple degrees each day into the weekend. Drier air
will also result in surface dew points falling into the low 60s,
which is quite comfortable for July standards.

The aforementioned cold front stalls over the northern Gulf States
before beginning to waver back northward. Our area appears to remain
on the cooler side of this boundary through the weekend but close
enough to warrant slight chance mention of showers and possible
thunderstorms, mainly for areas south of the Parkways.

Chances of showers and thunderstorms increase going into the
beginning of next week as the OH Valley resides between synoptic
scale features: one being the cut-off low over the Central Plains,
next is the Bermuda high over the Atlantic, and last is our
position south of the wavering boundary. This set up will allow for
rich moist air advection along return flow and a destabilized
environment.

&&

.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 756 PM EDT Tue Jul 16 2024

VFR evening with W to SW winds diminishing after sunset.  Main
challenge is timing and placement of storms developing overnight.
Look for convection to impact BWG beginning around 05Z, and pushing
east into LEX and RGA around 07Z. Will handle those with TEMPO
groups. Less confident in SDF as the focus is mainly south, but will
straddle daybreak with a PROB30 for storms. Heaviest part of the
storms will likely drop vis into IFR, but that will be brief so will
just go with low-end MVFR.

Low ceilings will linger well into Wednesday morning, perhaps with
some light precipitation, but expect the atmosphere to recover
around midday. Cigs should lift back to VFR, but the muggy air mass
and lingering boundaries will support enough of a storm chance to
warrant a PROB30 for TS/CB after 18Z. Winds generally due west
around 10 kt.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Flood Watch through Wednesday afternoon for KYZ023>025-030>037.
IN...Flood Watch through Wednesday afternoon for INZ076>079-083-084-
     089>092.

&&

$$

SHORT TERM...CJP
LONG TERM...CRG
AVIATION...RAS