875
FXUS63 KLMK 170545
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
145 AM EDT Mon Aug 17 2026

...Updated Aviation Discussion...

.KEY MESSAGES...

* Another round of showers and storms is possible late Sunday with
  an MCV moving through the region. Any storms that develop will
  have the capability of producing damaging winds and brief heavy
  rainfall.

* 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 mid and late week
  time frame, however temperatures should be slightly below normal
  for this time of year.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 229 PM EDT Sun Aug 16 2026

Currently, a MCV is tacking eastward from the Central Plains into
southern Iowa and northern Missouri. This system is expected to
continue eastward and move through southern IN bringing showers
storms to the Ohio Valley late tonight. Additionally, a frontal
boundary will continue to sink SE through today and move through the
area tonight.

There is a slight chance (20-30%) of isolated storms to develop this
evening ahead of the boundary, mainly in the northern half of the
forecast area. There is ample amounts of instability for any storms
to develop with an initiation trigger. Wind shear is marginal within
central KY, however there is an axis of 30-40kt shear in southern IN
due to a low level jet. With DCAPE near 1500 J/kg and PWAT values
around 2", any storms that do develop could have the potential for
severe winds and even microbursts.

Once the MCV moves into southern IN overnight, a cluster of storms
will track through the northern part of the CWA. SPC severe weather
outlook current has the area in a slight risk, specifically for
damaging winds. Confidence in timing has been on the lower side,
however HiRes models are finally somewhat in agreeance with the
system moving through. Storms will move in from the east around 1AM
EDT and makes its way to the Blue Grass between 4-6AM EDT.
Instability will start to erode with sunset, however 1500J/kg of
SBCAPE is still expected to hold on ahead of the system. The highest
amounts of wind shear values seem to be behind the system as a
shortwave disturbance moves into the region. The main threat with
these storms will be strong to damaging winds, while a localized
flash flooding threat is not out of the question.

The rain chances are done yet as there is a chances for some
isolated to scattered showers and storms to develop Monday
afternoon. At this time, there are no severe threats expected though
a rumble of thunder could still be possible. Aside from rain
chances, a relief in temperatures is expected starting Monday with
highs in the in the mid to upper 80s. Dewpoints are expected to
still be in the mid to low 70s, but will start to take a dip Monday
evening for a much nicer Tuesday.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 229 PM EDT Sun Aug 16 2026

Tuesday - Wednesday Afternoon...

The upper pattern will feature more of a zonal flow look as we move
into mid week, thanks to a flattened upper ridge over the southern
CONUS. Overall, this upper flow pattern looks to be void of any
notable shortwave activity, and with high pressure in place at the
surface this should be a dry stretch for us. Should see a good
amount of sunshine on Tuesday, however temperatures will be overall
cooler from the recent pattern, generally ranging between 85 to 90
degrees. Lows will also feel more comfortable in the mid and upper
60s.

The bulk of daylight hours on Wednesday should be dry, however we`ll
have to focus on timing of some shower and storm chances approaching
from the NW as a weak frontal boundary trailing from an eastern
Canada system drags toward the Ohio River Valley. We`ll continue to
carry some shower/storm chances across southern IN by Wednesday
afternoon to account for this. Ahead of any showers or storms, temps
are expected to warm to the upper 80s and low 90s across central and
southern KY. Southern IN and northern KY will likely be confined
more to the mid and upper 80s.

Wednesday Evening - Saturday...

Could have a fairly interesting setup for later Wednesday evening
into Thursday as the aforementioned front likely makes its way down,
or close to our region. In addition, models generally agree this
timing could be accompanied by the arrival of a shortwave embedded
in the digging eastern CONUS trough. The two features could be the
catalyst for fairly good coverage of showers and storms later
Wednesday evening into Thursday. It does appear that some decent
deep layer shear will be present thanks to the shortwave
enhancement, especially across our northern CWA. Tough to tell
whether it will overlap with the best instability, as placement of
the surface front could push things too far south to line up with
the best shear. Bottom line, there could be a chance for some
stronger storms here, but too early to tell given uncertainty in
exact placement of features.

Troughing across the eastern CONUS downstream of amplified upper
ridging across the western CONUS will be the pattern going into the
weekend. A couple of shortwaves embedded in the parent trough could
continue to rotate through the region going through Friday and
Saturday, potentially triggering additional showers and storms. This
will also keep temps a bit below normal for this time of year in the
low and mid 80s.

Saturday Night - Sunday...

Looks like the upper trough axis might push east by Sunday, leading
to a drier pattern to end the weekend. Temps will likely continue to
run just below normal in the low and mid 80s.

&&

.AVIATION /06Z TAFS THROUGH 12Z TUESDAY/...
Issued at 144 AM EDT Mon Aug 17 2026

A few showers and storms have developed near HNB and SDF, with a
lager cluster of storms over Illinois entering the region within the
next 1-2 hours. Very heavy rain, lightning, and gusty winds will
accompany these storms, impacting all terminals except BWG through
most of the morning hours. While ceilings should remain VFR, brief
MVFR visibilities are possible with heavier downpours. This cluster
should slowly dissipate as it moves east, departing out of the
region after 15z. Isolated to widely scattered showers and storms
could develop after 18z, with any activity dissipating by 00z. A
slow moving cold front will cause winds to shift from the SSW to the
NW for all terminals except for HNB from the late morning through
the afternoon hours, with winds steadily increasing during the
morning.

&&

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

&&

$$

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