701
FXUS63 KLMK 171740
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
140 PM EDT Wed Jul 17 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Periodic showers and storm continue through today, with a
    northwest to southeast drying trend expected tonight behind a
    cold front.

*   Cooler temps and lower dewpoints expected Thursday and Friday.

*   Gradual warm up this weekend with increasing mugginess by early
    next week. Shower and storm chances also return in that
    timeframe.

&&

.UPDATE...
Issued at 1103 AM EDT Wed Jul 17 2024

After a soggy morning with training showers and storms, we are in a
lull of precip activity as the environment is somewhat worked over
with MLCIN present and weaker moisture convergence. However, as we
get into the afternoon hours, do expect to see CIN deteriorate as we
get some daytime heating. With cloud cover lingering throughout the
day, the question remains how much heating and destabilization we
will realize. Do expect some isolated to scattered showers and
storms to redevelop along and ahead of the front this afternoon, but
knowing exactly where is challenging. Model soundings for this
afternoon do show a decent amount of instability available, but weak
shear will keep cells unorganized and messy. High PWATs will promote
heavy rainfall rates with any shower or storm. Some increase in
coverage may be possible this evening as the front passes just south
of the Ohio River, but we`ll see PoPs taper off from north to south
gradually through the night. Current forecast is on track and no
changes are planned at this time.


.UPDATE... Issued at 600 AM EDT Wed Jul 17 2024

Precipitation across the region has begun to transition to
light/moderate in nature as instability wanes and the main lifting
mechanism (outflow boundary) for convection has pushed south of the
TN border. The flood threat going forward should be minimal, so the
flood watch has been dropped a few hours early.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 309 AM EDT Wed Jul 17 2024

An east-west oriented band of showers and storms along a
boundary continue this morning across the width of Kentucky. Storm
motions have been generally been parallel to this boundary, which
prompted the issuance of a flood watch. Outflow boundaries from the
storms have aided in the development of new convection generally to
the south where better environmental parameters exist, and this has
helped to limit the overall storm training as the line propagates
southward. These storms are very efficient rain producers, as
evident of some recent obs... for example, the Marion County KY
Mesonet site recorded an inch of rain in nearly 15 minutes! So,
while the storm training threat has steadily decreased this morning,
localized flooding issues are still possible. Shower/Storm activity
should begin to taper down in coverage and intensity toward or
shortly after dawn.

Details regarding how the rest of the day will play out remain
uncertain. It does appear likely we`ll see some sort of lull in
precipitation after the current waves fizzles out, but models vary
on when/where new showers and storms will develop as a slow moving
frontal boundary sinks southward. Model performance over the last
few days has been sub-par at best, particularly with the finer
mesoscale features, so it`s hard to put confidence into a particular
solution or outcome. Based on some of the mesoscale and weak
synoptic forcing at play, have a general increase in PoPs as we go
into the afternoon hours, with drying/partial clearing from
northwest to southeast as the front slides through later today into
tonight.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 309 AM EDT Wed Jul 17 2024

Much cooler/drier post-frontal conditions can be anticipated
Thursday as northerly winds continue to pump in an air-mass with
Canadian (albeit, highly modified) origins. The surface high will
slowly track from the Midwest into the Great Lakes region Thursday
and Friday, keeping us solidly in a northern flow regime. Highs both
of these days will likely top out in the low/mid 80s with dewpoints
ranging from mid 50s to low 60s.

The upper level pattern will begin to shift going into the weekend
and early next week as a baggy, nearly stationary trough takes shape
over the Plains and Missouri Valley. Our region will be on the
eastern periphery of the trough, and we`ll see a gradual uptick in
low level moisture and mugginess going into next week. The increased
moisture will also lead to increasing shower and storm chances
during this timeframe.

&&

.AVIATION /18Z TAFS THROUGH 00Z FRIDAY/...
Issued at 140 PM EDT Wed Jul 17 2024

BKN clouds ahead of a cold front are resulting in MVFR ceilings this
afternoon. Some isolated to scattered showers will be possible
through this afternoon, and may increase in coverage this evening as
the cold front slowly sags south of the Ohio River. Do expect VFR
conditions behind the front, along with a sharp wind shift from the
north. There are some hints in the guidance of possibly seeing
ceilings lower to MVFR again for a brief period as the front
approaches BWG tomorrow morning. VFR will return to all sites for
tomorrow.

&&

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

&&

$$

UPDATE...DM/CJP
SHORT TERM...DM
LONG TERM...DM
AVIATION...CJP