726
FXUS63 KLMK 150157
AFDLMK

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

.KEY MESSAGES...

* Remaining hot and humid this week with more scattered rain and
  storm chances each day. Heavy rain, gusty winds, and lightning
  will be the main threats.

&&

.UPDATE...
Issued at 957 PM EDT Mon Jul 14 2025

Afternoon convection was limited today with weak lapse rates and a
lack of any strong forcing over the area. Still seeing a few
isolated showers, but lightning remains very limited. Expect that
trend to continue overnight given a juicy air mass with PWATs over 2
inches, but coverage doesn`t get anywhere close to 20 percent. No
changes planned to the going forecast.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 356 PM EDT Mon Jul 14 2025

This Afternoon and Evening...

Scattered clusters of showers and thunderstorms have developed
across the area this afternoon, with the stratus layer that was
along a decaying front now scattering out into a stratocu field over
central KY and southern IN. Temperatures have warmed into the mid
80s in most areas, with dewpoints typically in the low-to-mid 70s as
low-level moisture pools along the front. This has allowed for
modest amounts of instability, generally between 1500-2000 J/kg
MLCAPE on latest SPC mesoanalysis. Latest hi-res guidance suggests
that shower/storm coverage should remain isolated to scattered this
afternoon, especially as the mid-level wave associated with the sfc
front lifts to the north and east. The greatest coverage of showers
and storms according to CAMs will be over southern KY, with coverage
decreasing around sunset as we lose sfc-based instability.

Tonight...

The muggy air mass overhead will keep temperatures mild tonight as
low-level moisture settles after sunset. While an isolated shower is
possible across southwestern portions of the CWA, most of the area
should remain dry overnight. The main forecast challenge will be
if/how much fog develops tonight. While at least patchy fog looks
like a good bet for rural areas and valleys, there is still some
uncertainty if lingering cloud cover will keep fog from being more
widespread. For what it`s worth, the strongest fog signal in the 12Z
HREF guidance extends across the Bluegrass region and into eastern
KY, with more of valley fog signal present elsewhere. Lows Tuesday
morning should end up in the low 70s in most locations, with a few
upper 60s possible in the cooler valleys.

Tuesday...

No significant changes are expected in the large scale pattern for
tomorrow, with the warm and humid air mass remaining in place. Short
range models depict another convectively-enhanced mid-level
disturbance moving from the ArkLaTex to near the confluence of the
Ohio and Mississippi River tomorrow. This should provide some
additional support for showers and thunderstorms during the
afternoon, with several hi-res models showing greater coverage in
the vicinity of the MCV. Deep-layer shear values will still be
fairly weak on the order of 15 kt, so mostly disorganized showers
and storms are expected, with water-loaded stronger cells producing
gusty winds, heavy rainfall, and lightning. While cells should move
at around 15-20 mph, areas which have greater residence time of
heavy rain could see localized flooding. Highs on Tuesday should be
fairly similar to today in the upper 80s and lower 90s.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 356 PM EDT Mon Jul 14 2025

Medium-range guidance consensus continues to show a fairly static
synoptic pattern late this week and through the weekend as a belt of
faster zonal flow continues across the northern US and southern
Canada while ridging shifts back and forth between a typical Bermuda
high setup and a southern Plains setup. With no large-scale forcing
to shift the pattern, like the way the previous forecast describes
the "rinse and repeat" setup, as each day should be fairly similar
weather-wise. In general, expect seasonally hot and humid conditions
with temperatures ranging from the upper 80s to the mid 90s for
highs and low-to-mid 70s for lows. With dewpoints remaining in the
low-to-mid 70s through the extended period, afternoon heat indices
should peak in the upper 90s and lower 100s, with the highest heat
indices expected Thursday afternoon. While conditions should be
fairly uncomfortable each afternoon, expected heat indices aren`t
out of the ordinary for mid July and should be below advisory
criteria.

Daily scattered shower and thunderstorm chances will peak in the
afternoon and evening and diminish for the nighttime and morning
hours. With the band of stronger mid- and upper-level westerlies
staying well to the north, wind shear will remain weak, and
convection will remain largely disorganized. Coverage will likely be
variable from day-to-day as increased coverage would be expected in
the vicinity of smaller-scale shortwaves in the zonal flow aloft. In
general, garden-variety showers and storms with localized gusty
winds and heavy rainfall can be expected each day. The main threats
from these storms should be localized flash flooding due to longer
residence time of heavy rainfall.

&&

.AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 756 PM EDT Mon Jul 14 2025

Quite a bit less convective activity showing up compared to the last
two evenings, mainly due to the relative lack of forcing. A few tall
showers, perhaps with a few rumbles of thunder, are ongoing over
southwest Indiana and merit an early TEMPO group in HNB. Would
expect that any lasting restriction to vis would likely be MVFR,
though we can`t rule out a brief IFR vis in the heaviest rain.

Stagnant and humid air mass overnight will support at least some fog
formation, but we`ll go with a prevailing MVFR for all except SDF,
and include a TEMPO for IFR vis at RGA around daybreak. Any fog at
the terminals will be short-lived, with conditions recovering to VFR
by mid-morning. SW winds less than 10 kt with a mid-level cig in the
afternoon.

&&

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

&&

$$

UPDATE...RAS
SHORT TERM...CSG
LONG TERM...CSG
AVIATION...RAS