197
FXUS63 KLMK 211905
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
305 PM EDT Fri Aug 21 2026

.KEY MESSAGES...

* A cold front will bring a chance for showers and storms Saturday
  afternoon. A few storms may become strong east of I-65, with the
  main severe hazards being gusty winds and small hail.

* Milder, dry conditions are expected for Sunday through Tuesday.

* Warming temperatures and low rain chances return by the middle of
  next week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 304 PM EDT Fri Aug 21 2026

This Afternoon through Tonight...

A scattered cu field has developed across the area this afternoon as
locations reach convective temperatures in the low-to-mid 80s. Where
there is slightly greater instability and convergence around Lake
Cumberland, isolated to widely scattered showers and storms have
developed, and should continue over the next few hours before
diminishing by around sunset.

Tonight, mostly clear skies and light winds should allow for
efficient cooling after sunset, with temperatures falling into the
upper 60s and low 70s for the overnight hours. Light winds in the
boundary layer should allow for patchy fog to develop after
midnight, with dense fog possible in sheltered valleys. Fog coverage
may be limited early Saturday morning if residual clouds from
upstream convection make it into southern IN and north central KY.
Otherwise, dry conditions and low temperatures ranging from the mid
60s to the low 70s are expected.

Saturday and Saturday Night...

Within broad upper level troughing, a shortwave will eject from the
Canadian Prairies into the upper Ohio Valley tonight into Saturday,
bringing an associated sfc cold front across the area during the
daytime hours. Temperatures should again warm into the low-to-mid
80s by midday, with a narrow corridor of low 70s dewpoints and 2500-
3000 J/kg SBCAPE expected just ahead of cold FROPA. The best
lift/forcing associated with the upper shortwave is expected to
remain across Ohio and points to the east tomorrow, and it appears
that most of the forcing which would support convective development
across our area would come from the front itself. Accordingly, how
far east the front makes it before convective temperatures are
reached Saturday afternoon will determine where the greatest
potential for showers and storms will be. 12Z HREF probabilities of
>40 dBZ reflectivities are highest along and east of I-65, with
lower chances of showers and storms expected in the western CWA.
Still, with relatively modest forcing, would expect storm coverage
to be isolated to scattered even east of I-65, with many areas
remaining dry.

Where storms develop, mean deep-layer shear values of 20-25 kt would
support modest storm organization, with a few longer-lasting and
taller storms possible. Shear profiles are fairly unidirectional, so
damaging straight-line winds would be the main severe threat in any
stronger storms. A couple instances of near-severe hail will also be
possible in the tallest storm cores, though mid-level lapse rates
won`t be particularly steep. The storm window should be fairly
narrow tomorrow afternoon between around 2 PM and 1-2 hours after
cold FROPA, with the storm threat completely ending by around sunset.

Saturday night, drier air will begin to work into the region behind
the cold front along with modest cool air advection. The pressure
gradient associated with the front won`t be particularly strong, so
NW winds behind the front should ease outside of the elevated/well-
mixed areas. Temperatures should be cooler Sunday morning, with lows
falling into the low-to-mid 60s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 304 PM EDT Fri Aug 21 2026

A drier and marginally cooler air mass will spill into the Ohio
Valley from the northwest behind the cold front on Sunday as mid-
and upper-level troughing sets up east of the Mississippi. This air
mass, supported by 1018 mb sfc high pressure, should remain in place
over the region into Monday, with sub-1" PWATs indicating moisture
levels around the 10th percentile of model climatology. It should be
rather comfortable for late August during this time period, with
highs in the upper 70s and low-to-mid 80s and lows in the upper 50s
and low 60s.

The primary trough axis over the eastern CONUS will begin to eject
to the east Monday night into Tuesday as upper ridging over the
western CONUS spreads toward the lower Miss. Valley. This should
allow a sfc warm front to creep to the NE next Tuesday, with greater
moisture located in the vicinity of the front. If the front remains
SW of the area, as is currently the most likely solution, dry
weather should continue into the middle of next week. However, if
the ridge/warm front can make it closer to the area, low-end chances
for showers and storms may return by next Wednesday. Next Wednesday
into Thursday, another upper shortwave is expected to descend on the
NE side of the ridge across the upper Midwest. This may bring a weak
front toward the area, prompting a return of shower/storm chances,
though forecast confidence in storms is low at this time.
Temperatures should gradually increase by the second half of next
week, returning to near climatological normals by next Wednesday and
Thursday.

&&

.AVIATION /18Z TAFS THROUGH 00Z SUNDAY/...
Issued at 117 PM EDT Fri Aug 21 2026

Scattered to broken VFR clouds will continue through the afternoon,
dissipating around sunset. Northerly winds will switch to southwest
Saturday morning, then increase again from the west-northwest behind
a pre-frontal trough around midday. A low chance for
thunderstorms will exist mid to late Saturday afternoon,
primarily at LEX and perhaps RGA, but that (20-23z Saturday) is
after the current TAF period.

&&

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

&&

$$

SHORT TERM...CSG
LONG TERM...CSG
AVIATION...JRB