638
FXUS63 KLMK 231902
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
302 PM EDT Sun Jun 23 2024

.KEY MESSAGES...

*   Isolated storms are possible this evening, with torrential
    downpours and gusty winds the main threats.

*   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.

&&

.SHORT TERM /THROUGH MONDAY/...
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 /MONDAY 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 /18Z TAFS THROUGH 00Z TUESDAY/...
Issued at 132 PM EDT Sun Jun 23 2024

A cold front poised just north of the Ohio River at issuance time
will push southward across central Kentucky this afternoon, sparking
scattered showers and storms. While prevailing conditions will be
VFR once the morning low clouds lift a bit more, TSRA will be
capable of producing well below VFR flying conditions (mostly in
terms of low vsby in heavy downpours) and enhanced wind gusts.

Storms will dissipate and move out of the region this evening as the
cold front moves off to the southeast. Clear skies and light winds
will be the rule tonight ahead of high pressure over Illinois.
Valley fog can be expected by dawn, but more widespread general fog
is more in question. Before introducing vsby restrictions in the
TAFs for early morning BR/FG, will see where rain falls this
afternoon and then re-evaluate for the 00Z package.

&&

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

&&

$$

SHORT TERM...13
LONG TERM...BTN
AVIATION...13