-- Discussion containing changed information from previous version are highlighted. --
630
FXUS63 KLMK 240508
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
108 AM EDT Mon Jun 24 2024

.KEY MESSAGES...

*   The Heat Index may rise above 100 degrees on Tuesday, especially
    west of the I-65 corridor.

*   Another round of scattered showers and storms will be possible
    Wednesday ahead of a frontal boundary.

&&

.UPDATE...
Issued at 943 PM EDT Sun Jun 23 2024

Cold front is draped roughly along or just north of the Western
Kentucky and Bluegrass Parkways, with isolated convection just a bit
to the south. These storms are putting out some lightning and brief
heavy downpours, but otherwise haven`t been very tall or strong due
to meager mid-level lapse rates. Current forecast appears to be on
track with this activity winding down around midnight as the cold
front continues its southward push.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 301 PM EDT Sun Jun 23 2024

At the start of the period a cold front will be draped across
central Kentucky, likely accompanied by scattered showers and a few
thunderstorms. Convection will begin to weaken as the sun sets and
end entirely as the front pushes southeastward out of the area by
late evening. Cooler, drier air will then move in behind the front
under clearing skies. Patchy fog will develop by early Monday
morning, especially in sheltered river valleys and where rain had
fallen Sunday afternoon/evening.

During the day on Monday high pressure will slide from Illinois to
Ohio, providing our region with sunny skies and a light north
breeze. The full late June sunshine will pull temperatures into the
middle and upper 80s, with the more urban locations touching 90.
However, afternoon dew points should mix down into the middle and
upper 50s, which for much of the area would be the lowest dew points
we`ve seen since June 16.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 301 PM EDT Sun Jun 23 2024

The overall pattern through the long term will feature an upper
ridge center predominantly over the Desert Southwest and the Four
Corners region and slight troughiness across the eastern US. This
will place the Ohio Valley along the main flow between the two
features and allow the next system to work across the region Tuesday
night into Wednesday. This is likely our best chance at widespread
measurable QPF for the CWA. The western ridge will break down and
flatten out for the second half of the week featuring a more zonal
flow over the Ohio Valley as sfc high pressure builds in behind the
departing system Thursday and Friday. Drier air and lower dew points
will mean a little respite from the humidity and even the heat for
Thursday. By the weekend the break is over as the upper ridge builds
back across the South and the Lower Mississippi Valley with
increased heat and humidity and another chance of showers and
thunderstorms.

Tuesday looks to be the hottest day of the week as the above
mentioned ridging to our west noses eastward into the Ohio Valley.
With sfc high pressure just off to the southeast, dew points will
climb back into the upper 60s to near 70 allowing for heat index
values to be at or near 100 degrees (especially west of I-65).

A weak shortwave trough will work out of the Northern Plains through
the Great Lakes during the day on Wednesday. This will help push a
cold front through the Ohio Valley and provide enough lift for the
development of widespread showers/storms. Current forecast QPF
values look to be on average between a quarter to three quarters of
an inch but with PWAT values of 2.00" to 2.25" ahead of the cold
front, could see localized higher amounts from any convection that
develops. Speaking of convection, we will also need to watch
Wednesday for the potential of strong to severe storms as there will
be plenty of instability and a fair amount of shear for organized
convection. Main threat currently looks to be damaging wind gusts
and hail.

Significantly drier and cooler air will advect in behind the
departing system Wednesday night into Thursday. Dew points will fall
from the upper 60s/low 70s on Wednesday to the low/mid 60s by
Thursday. Lows Thursday morning will be in the low/mid 60s and highs
a touch below normal in the mid 80s. This break in the heat is short
lived as the upper ridge across the southern US begins to strengthen
and build northward for the end of the week into the weekend. Friday
will see a return of highs in the low/mid 90s but Saturday looks
even hotter with increased moisture allowing for head index values
to be near or in the low 100s. Another system looks to work across
the region for the weekend with an increased chance of
showers/storms. Deterministic models vary greatly on timing so for
now will stick with NBM which appears to be more in line with the
12z run of the ECMWF which has the higher PoPs Saturday night into
Sunday.

&&

.AVIATION /06Z TAFS THROUGH 12Z TUESDAY/...
-- Changed Discussion --
Issued at 107 AM EDT Mon Jun 24 2024

Shower and storm activity has pushed south of the terminals this
hour. Winds generally will be from the northwest and bring in drier
air. Given LEX had rain around sunset, don`t want to give up on the
idea of a brief lowering of vsby, but dry air pushing in should
offset that enough to keep them VFR. Stronger northerly winds are
expected during the day Monday before they lighten up again in the
evening hours.
-- End Changed Discussion --

&&

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

&&

$$

UPDATE...RAS
SHORT TERM...13
LONG TERM...BTN
AVIATION...RJS