-- Discussion containing changed information from previous version are highlighted. --
063
FXUS63 KLMK 250134
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
934 PM EDT Mon Jun 24 2024

.KEY MESSAGES...

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

*   Isolated to scattered showers and storms possible late Tuesday
    afternoon into the evening.

*   Widespread shower and scattered storm chances Wednesday,
    bringing much needed rain to the region.

&&

.UPDATE...
-- Changed Discussion --
Issued at 934 PM EDT Mon Jun 24 2024

Sfc high pressure overhead will retreat east into the Appalachians
overnight, but we`ll maintain seasonal temps and less muggy
dewpoints into Tuesday morning. Look for hot return flow to set up
out of the SW mid/late morning. Convection will develop over
northern Illinois and Indiana in the late morning or early
afternoon hours, but that will struggle to advance southward
into quite a capped atmosphere. Will need another source of
lift which won`t come until at least Tue evening. Current forecast
remains well on track.
-- End Changed Discussion --

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 310 PM EDT Mon Jun 24 2024

High pressure over the upper Ohio Valley and a mostly dry atmosphere
will lead to clear skies and light winds for southern Indiana and
central Kentucky tonight. Low temperatures should once again be in
the 60s, and some valley fog will again be possible in the Lake
Cumberland region by dawn.

The heat and humidity will turn back on tomorrow as return flow
brings warmth and moisture to the region. Highs are expected to be
in the lower and middle 90s. Dew points west of I-65 will climb back
up to around 70 degrees, creating peak afternoon heat index values
around 100.

Can`t rule out isolated thunderstorms by late Tuesday afternoon,
possibly on outflow from earlier convection to our north. Synoptic
scale deep layer shear will be very weak, but there will be plenty
of instability and enough moisture to support storms if any can get
going, especially in southern Indiana.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 310 PM EDT Mon Jun 24 2024

The cold front will approach from the northwest Tuesday night and
move through the region sometime around Wednesday afternoon, though
there will likely be myriad convectively induced boundaries in the
area Tuesday night and Wednesday as well. There will be plenty of
moisture available to support multiple rounds of showers and storms.
How much instability will be present is tough to nail down given the
presence of widespread clouds and occasional rain, but the SPC Day 3
MRGL looks good for some storms producing locally gusty winds with
the heavier downpours. Models have been quite consistent with this
system and there is reason to be cautiously optimistic that many
spots can receive beneficial rainfall with it mid-week.

Thursday and Friday look dry and very warm as high pressure
advances from the Great Lakes to New England. A large upper ridge is
expected to develop over much of the southern half of the country by
late week, with afternoon temperature readings into the lower and
middle 90s by Friday.

Shower and storm chances return to the forecast this weekend as the
next cold front pushes through, with the best chances of rain
Saturday night into Sunday morning. While some stronger storms can`t
be ruled out, the main impact of this system appears to be another
chance for beneficial summertime rains. It will be interesting,
though, to see just how far south the front can make it given the
moderately strong 5H ridge that is progged to set up for the
southeast U.S. Friday-Tuesday. Speaking of which, after a hot day on
Friday another hot one is expected for Saturday ahead of the front
and under the edge of the upper ridge, with afternoon readings
currently pegged in the middle 90s.

&&

.AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 714 PM EDT Mon Jun 24 2024

VFR conditions expected through the valid TAF period. Look for light
winds overnight as northerly flow diminishes with the loss of
mixing. Will keep light/variable overnight for most, but SDF could
follow its usual tendency to settle into a light SSE flow.

Winds start to veer and increase around daybreak, with modest SSW
winds by midday. Sustained winds will be just over 10 kt through the
afternoon with some gusts just shy of 20 kt.

Biggest question mark comes into play very late in the afternoon,
mainly affecting the planning period at SDF. Synoptic models want to
show convection to our north with the main sensible weather impact
being a cooling outflow boundary pushing in around 23Z. Confidence
is too low to include it yet, but we will revisit the question in
later issuances.

&&

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

&&

$$

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