464
FXUS63 KLMK 141753
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
153 PM EDT Mon Jul 14 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

* Remaining very warm and humid for most of next week with more
  scattered rain and storm chances each day. Heavy rain, gusty
  winds, and lightning will be the main threats.

&&

.UPDATE...
Issued at 1017 AM EDT Mon Jul 14 2025

A washed out front extends SW to NE across the Ohio Valley this
morning, with a stratus deck and scattered sprinkles showing up
along the front on latest radar and satellite imagery. Across south
central KY, more sunshine earlier this morning has allowed for
temperatures to warm to around 80 as of 14Z, with temperatures
generally in the mid 70s across the rest of central KY and southern
IN. Residual energy from an MCV which moved across the MO Bootheel
and western KY earlier this morning has now made it into our
southern KY counties, helping to spark isolated to scattered showers
and thunderstorms. The most robust of these cells is currently over
Simpson County; while brief gusty winds and heavy rainfall are
likely with these cells, generally not expecting severe weather from
these storms.

For the rest of the morning and into the afternoon, would expect
light sprinkles and stratus to gradually lift into a stratocu layer
as daytime heating increases. Given high PW values and modest
instability this afternoon, would expect scattered showers and
thunderstorms to develop along and south of the front. As a result,
shower/storm coverage should be less across southern IN, though
we`ll still keep an isolated PoP in there. While overall shear is
weak, some enhancement from the residual of the MCV could lead to
one or two stronger storms, especially across southern KY.
The forecast remains on track at this time.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 248 AM EDT Mon Jul 14 2025

We`re in a relative quiet period early this morning as evening
convection has moved on, and we await the next subtle MCV coming
from upstream clusters of showers and storms. Any lingering showers
or a stray t-storm this morning will likely be initiated by what is
coming out of the MO Bootheel at the moment. Later this afternoon,
we do expect moderate instability to develop on the order of 1500-
2500 J/KG of ML CAPE, especially across our SW CWA which will have
slightly higher Td`s, and may see a bit more sunshine. This is the
main driver for the SPC Marginal Risk (wind) down there. Not overly
impressed with severe chances, but can`t rule it out either. We`ll
be situated beneath the right entrance of a weak mid to upper level
impulse, and that combined with a weak surface front draped near the
Ohio River should be enough to initiate scattered showers and storms
once again through the PM hours.

As has been the case, deep layer shear is pretty weak around 15
knots, however the moderate instability will likely be strong enough
to support a few briefly stronger updrafts before they collapse.
Overall, look for pulse/garden variety storms capable of brief heavy
rainfall, and gusty winds. The bigger focus will be the continued
high PWAT airmass (~2" through the column), which combined with slow
storm movement can create some locally higher rainfall amounts.
Overall, should be enough movement and scattered coverage to
mitigate larger concerns.

Temps will be a couple degrees cooler than yesterday given more
cloud cover, and the weak frontal boundary impinging on the area.
Looking for mostly upper 80s for highs, with mild lows tonight once
again in the low to mid 70s. Convective activity should diminish
later this evening past sunset as we lose surface based instability.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Issued at 248 AM EDT Mon Jul 14 2025

The long term forecast looks very much like a "rinse and repeat"
type of pattern that will promote mainly diurnally driven shower and
storm chances each day. Even temperatures will behave fairly steady
state as highs are expected to be in the upper 80s and low 90s each
day, with mild overnight lows mostly in the low and mid 70s. These
types of patterns are also patchy fog mornings, especially near
water bodies and any areas that received previous heavier rainfall.

We start Tuesday on the NW periphery of a SE CONUS upper ridge.
Along this periphery, we`ll continue to see a slow moving train of
weak MCV`s stretching from the Red River Valley region up through
the middle Mississippi River Valley. This should be the main trigger
for Tuesday which will most likely bring the best coverage of PM
storms to our western CWA.

AS we get into mid week, and then expanding into late week and the
weekend, the upper ridge will suppress just a bit, and a belt of
zonal westerlies will sink into our region. The end result will be a
weak frontal boundary trailing an eastern Canada surface low that
will sink down near or into our area through mid to late week. At
the very least, this will act as a weak triggering mechanism, and
may help to keep temps suppressed just a bit (still above normal).
Overall, deep layer shear should remain pretty weak, so still
expecting mostly pulse/garden variety storm modes. It is possible to
get some briefly enhanced deep layer shear values with any weak wave
embedded in the stronger westerlies aloft, however timing or having
much confidence in any one time period is difficult at this time
series. Bottom line is to expect a pretty typical summer time
forecast with scattered shower and storm chances each afternoon
among temps slightly above normal for this time of year. Plenty of
sunshine will also occur during this stretch, especially each
morning and early afternoon.

&&

.AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 152 PM EDT Mon Jul 14 2025

Scattered showers and isolated thunderstorms are currently forming
across the area and are expected to continue this afternoon,
gradually diminishing around sunset. Outside of showers and storms,
ceilings should remain VFR through this evening. With a weak front
over the area, winds will be light and variable between the SW and
W/NW through around sunset.

Tonight, moisture in the vicinity of the front and light/calm winds
will promote the development of fog and/or low stratus. Confidence
is low-medium on how much categories will fall, with the main window
for fog development being between 15/07-12Z. While some guidance is
showing IFR or lower visibilities, due to low confidence, will
advertise MVFR conditions for now. By mid-morning, any fog should
lift into a stratocu layer, with brief MVFR CIGs possible as the
moisture mixes upward.

&&

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

&&

$$

UPDATE...CSG
SHORT TERM...BJS
LONG TERM...BJS
AVIATION...CSG