898
FXUS63 KLMK 160557
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
157 AM EDT Sun Aug 16 2026

...Updated Aviation Discussion...

.KEY MESSAGES...

* Hot and humid conditions this weekend with highs in the low/mid
  90s and heat indices up to 109 degrees both days. Heat Advisory is
  in effect this weekend for a large portion of southern IN, central
  and southern KY.

* Scattered showers and isolated storms are possible (20-30% chance)
  across areas mainly east of a Salem, Indiana to Richmond, Kentucky
  line this afternoon and evening. Any storms that form could
  produce strong to damaging winds.

* Another round of showers and storms are possible late Sunday ahead
  of a cold front moving through the region. Any storms that become
  severe would be capable of producing damaging winds.

* A reprieve from the hot and humid weather, as well as showers and
  storms, comes Monday evening once the cold front departs to the
  south. Showers and storms arrive again for the late week time
  frame, however temperatures should be slightly below normal for
  this time of year.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 233 PM EDT Sat Aug 15 2026

Currently, isolated showers and storms are developing to the east of
the forecast area. A few have developed over the Blue Grass region,
but have not been severe. Storm development has the ability to
continue through this evening as the environment is plenty unstable
with the diurnal heating. The combination of weak mid level lapse
rates and weak to marginal deep layer shear should limit overall
storm intensity.

An upper level ridge continues to hold over the region, bringing
mostly clear skies and warm temperatures. A Heat Advisory remains in
effect through Sunday evening for areas west of the Bluegrass. Heat
indices are expected to reach triple digits again Sunday with a 80-
90% chance of greater than 100F west of I-65. As the ridge begins to
decay due to a trough building in the west, the Ohio Valley will
transition to a nearly zonal upper level flow.

A frontal boundary is expected to start pushing through the area
Sunday evening with a weak surface low. This has the potential to
bring in a broken line from the NW Sunday evening into the night
hours. The main hazard for these storms would be strong to damaging
winds, with PWAT values 2"+ throughout the whole area and 1000-1500
J/kg of DCAPE Sunday evening. Additionally, an MCV is forecasted to
develop over Nebraska and Kansas and track over south central
Indiana. Guidance is bringing another round of storms through Sunday
night into the early morning of Monday. The environment remains
marginal with 15-20kts of low level shear and roughly 1500J/kg of
SBCAPE. Overall confidence in these two systems are low as it will
depend of the MCV development and where is tracks.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 233 PM EDT Sat Aug 15 2026

Monday - Monday Night...

We`ll keep shallow amplitude NW flow aloft in place on the NE
periphery of the upper ridge through much of the upcoming work week.
Expect isolated to scattered shower and storm chances in the
forecast for Monday as a surface cold front trailing from a weak New
England surface low slides south across our CWA. There may be just
enough overlap between modest deep layer flow yielding 25-30 knots
of 0-6 km shear, and moderate instability characterized by 1500-2500
J/KG of ML CAPE. However, the best shear will be farther north, and
with the front sliding SE through the day, it appears any window for
that overlap would be pretty short. Just a general t-storm risk on
the current Day 3 Outlook, and that seems reasonable for now. Any
better overlap timing between the two may end up yielding a Marginal
Risk so will keep an eye on that trend.

The frontal boundary sinking south will start to provide some relief
from the heat and humidity across our northern CWA through the day.
It will still be hot and humid across southern KY on Monday ahead of
the front, and will be looking for low 90s for highs along with max
heat indices approaching 100F. Monday night should trend dry with
the loss of heating, with lows settling into a more comfortable 65
to 70 degree range.

Tuesday - Wednesday Afternoon...

The upper ridge will retrograde to the SW CONUS through mid week,
allowing slight more established NW flow over our area. Doesn`t look
to be a lot of notable shortwave activity embedded in the flow
through mid week, and this combined with surface high pressure
building in behind the passing cool front we should see mostly dry
conditions through Wednesday. Highs should mostly range between 85
to 90 each day, although southern KY could reach the low 90s again
by Wednesday. Makes sense being closer to the upper ridge.

Wednesday Evening - Saturday...

Shower and storm activity looks to pick up again as early as
Wednesday evening, and through much of the late week, as a cool
front trailing from an anomalously strong eastern Canada system
drops south into our area. In addition, models generally agree in
increased shortwave activity embedded with in the NW flow aloft
still in place over our area. With multiple triggers in place, we`ll
carry shower and storm chances through late week into the weekend.
The shortwaves should help to continually reinforce slightly cooler
air across the region, and temps will run below normal for this time
of year in the low and mid 80s for much of this time. It is possible
that troughing gets established well enough by Saturday that more of
the convective activity is off to our south and east and we stay
drier, however confidence is low given model variability for now.

&&

.AVIATION /06Z TAFS THROUGH 12Z MONDAY/...
Issued at 155 AM EDT Sun Aug 16 2026

VFR conditions will prevail across the terminals through 00z this
evening. There were a few showers and storms nearby LEX over the
past few hours, but have since diminished and departed to the
south. WSW winds will steadily increase during the daytime hours
Sunday, with gusts up to 17 kt possible in the afternoon for SDF and
LEX. Chances for showers and storms will increase after 00z for all
terminals except BWG, with Prob30 groups introduced in the TAF
package. While ceilings will remain VFR, heavier downpours with any
showers and storms that develop could cause brief reductions in
visibility.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Heat Advisory until 9 PM EDT /8 PM CDT/ this evening for
     KYZ023>031-034-038-039-045-046-053-054-061>065-070>078-
     081-082.
IN...Heat Advisory until 9 PM EDT /8 PM CDT/ this evening for
     INZ076>078-083-084-089>092.

&&

$$

SHORT TERM...CAL
LONG TERM...BJS
AVIATION...BEN