773
FXUS63 KLMK 182328
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
728 PM EDT Fri Jul 18 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

* Scattered storms linger through this evening, mainly in south-
  central Kentucky. Storms could produce gusty winds, torrential
  rainfall, and frequent lightning.

* Scattered to numerous showers and thunderstorms are likely
  Saturday, which could result in some instances of flash flooding.

* Active weather pattern will continue Sunday through Tuesday, with
  episodic bouts of showers and storms. Excessive rainfall and
  flooding will be possible in areas that see repeated rounds of
  storms.

* Hot and very humid mid to late next week, with peak afternoon heat
  index values well over 100. Heat indices of 105-110 are possible.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 334 PM EDT Fri Jul 18 2025

A quasi-stationary boundary lingers from ENE to WSW across north-
central KY this afternoon, with ongoing scattered convection in a
very moist, unstable environment south of the boundary. Anomalous PW
of 2.0-2.2 inches is still noted across the region along this
boundary, which is supporting high rainfall rates (briefly exceeding
1-2 in/hr) in any and all convection. Fortunately, large scale
forcing is nonexistent today with only weak background height rises
aloft. Thunderstorm coverage is more scattered in nature compared to
yesterday, with a reduced overall flooding threat due to the lower
coverage and reduced training potential. However, some isolated west
to east training remains possible across south-central KY. Very
localized flash flooding is possible in any areas that see training
convection.

Temperatures continue to warm into the 85-90 degree range outside of
storms. This is producing heat index values of 95-100 due to the
oppressive humidity still in place. Showers and storms will decrease
in coverage tonight, but isolated activity will remain possible
through most of the overnight period. Temperatures will drop back
into the low to mid 70s.

Saturday, a mid-level wave/MCV will move across IL and IN. Hi-res
models continue to point to a rather large complex evolving
southeast across portions of IA and IL. As these storms push
southeast, scattered convection appears likely to develop out ahead
of it across southern IL/IN during the mid to late morning hours.
This will likely enhance rainfall totals along and just north of the
I-64 corridor through the morning and early afternoon hours. Given
yesterday`s (Thursday) heavy rain footprint and reduced FFG, there
is concern for scattered instances of flash flooding across southern
IN and north-central KY. Considered a Flood Watch for the northern
CWA. However, there is enough uncertainty in the hi-res CAM output
for the PM hours to hold off on a watch at this time. Convective
evolution Saturday afternoon and evening is messy/problematic, but
scattered to numerous showers and storms do appear possible. PW
values lingering between 2.0-2.2 inches will support very efficient
rainfall production, and any training will boost the flooding risk.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 334 PM EDT Fri Jul 18 2025

Sunday into early next week, an upper level ridge will remain over
the Southeast with our region residing along a baroclinic zone. A
very warm, humid airmass will linger across the region. An extremely
moist airmass will remain in place across the region with PW values
near 2 inches.

As we move into Sunday, the upper level ridge looks to retrograde
slightly to the west with heights building across the Plains.  This
will allow our upper level flow pattern to become increasingly more
northwesterly with time.  The overall baroclinic zone will shift
from a zonal type regime to a northwest-southeast oriented one from
the Midwest down into the eastern Ohio Valley.  With our region
remaining on the periphery of the southeast ridge, we`ll have to
watch for more MCVs and perturbations that will bring clusters of
showers/storms to the region mainly in the Sunday through Tuesday
period. Storms during the period may be strong to marginally severe
with mainly a wind damage threat due to waterloaded downdrafts. The
storms will also be capable of torrential rainfall and the repeated
nature of heavy rainfall potentially training over the same areas
may result in an enhanced flood risk across portions of the region.
Daytime highs will be in the mid-upper 80s to near 90 with overnight
lows in the lower-middle 70s.

By Wednesday of next week, there continues to be an increase in
forecast confidence that the mid-level ridge will start to expand
and shift the storm track away from the region. While that will
lower the heavy rainfall potential, it will also result in an
increase in temperatures with no relenting of the humidity. Highs by
mid-late next week will warm daily into the low to mid 90s.
Dewpoints will remain in the low to mid 70s, resulting in afternoon
heat indices well above 100. There is a concern for multiple days of
excessive heat, which will increase the risk for heat-related
illnesses.

&&

.AVIATION /00Z TAFS THROUGH 06Z SUNDAY/...
Issued at 727 PM EDT Fri Jul 18 2025

VFR conditions are ongoing at the airfields at this moment, though
we do have some isolated to scattered heavy rain and thunderstorms
across the region. These storms are expected to impact BWG at the
start of the forecast period, but do expect improving conditions
later this evening. Elsewhere, VFR is expected to continue, with
lower confidence in any lingering storms to impact any other
terminals.

By tomorrow morning, a signal for low stratus continues, with cigs
possibly dropping to MVFR for a few hours after sunrise. Eventually
we will return to VFR as the stratus breaks out, but additional
showers and storms are possible during the afternoon again. Not
confident in any one area seeing more storms over another, so did
blanket PROB30 groups for the end of the forecast period.

&&

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

&&

$$

SHORT TERM...EBW
LONG TERM...MJ/EBW
AVIATION...CJP