711
FXUS63 KLMK 141917
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
317 PM EDT Tue Jul 14 2026

.KEY MESSAGES...

* Dry through tomorrow, except a low (20-30%) chance for an
  afternoon or evening storm mainly over southern Kentucky. Daily
  storm chances begin to increase on Thursday.

* Rain and thunderstorm chances peak Friday into Saturday,
  especially during the afternoon and evening hours. Slow-moving
  storms will be capable of locally torrential rainfall, lightning,
  and gusty winds.

* Outside of storms, heat indices will peak in the 97-103 degree
  range each afternoon through at least Friday.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 315 PM EDT Tue Jul 14 2026

Tuesday afternoon, between a ridge of high pressure over the
Midwest/Great Lakes and a cutoff low across the Deep South,
easterly flow was in place across central Kentucky and southern
Indiana. The northern extent of deep layer moisture was evident
in the more extensive cu field across southern Kentucky where
RAP mesoanalysis revealed 1500-2500 J/kg SBCAPE. Fortunately,
effective bulk shear in these areas was only 20-25 kt, with the
higher shear values displaced to the north. Even so, the steep
low level lapse rates and increasingly dry mid levels across the
area are resulting in DCAPE values of 900-1300 J/kg (highest in
western KY), which would support gusty outflow winds with any
thunderstorm that manages to fire this afternoon and evening.
Fortunately, the probability of storms over our area is low;
HREF neighborhood probabilities for >40 dBZ peak around 20-40%
between 5 and 11 pm EDT this evening across areas south of an
Everett to Burkesville line.

Tomorrow looks like a similar set up, though with the ridge sinking
south over the Ohio Valley subsidence should limit storm coverage
even more compared to today. Still, around a 10-20% chance for a
pop-up storm will exist area-wide during the afternoon and evening
when strong surface heating may result in convective temperatures
(around 88-91 degF) being reached.

Shower and storm chances will increase slightly on Thursday as
ridging weakens and remnant energy from the aforementioned low
begins to move back towards our area from the southwest. The Rapid
Ensemble Forecast System (REFS) mean brings PWATs up to around 2
inches across the area Thursday afternoon, while keeping 0-6km bulk
shear generally under 15 kts. This suggests that any storms that
develop will be both efficient rain-producers and slow-movers,
capable of dropping locally heavy rainfall - though storm coverage
will still be relatively low at around 25-40%.

Outside of any afternoon and evening storms, it`ll be seasonably
warm and increasingly humid the next couple days with afternoon
highs in the upper 80s to low 90s and overnight lows in the low to
mid 70s. Daily heat indices will peak in the upper 90s to around
103, resulting in minor to moderate heat risk - suggesting an
increased chance of heat related illness among vulnerable
populations.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 315 PM EDT Tue Jul 14 2026

===== Friday - Saturday =====

A gradual weakening of the upper level ridge begins Friday and
continues into next week. A weak, mid-level shortwave disturbance is
forecast to drift over the Lower OH Valley Friday into Friday night.
Meanwhile, the first in a series of stronger shortwave troughs will
drop southeast over Canada before rotating across the Great Lakes
this weekend.

We`ll have a very warm, moist airmass and weak low-level SW flow in
place ahead of the mid-level impulse. LREF mean PW values are
forecast to approach 2 inches Friday and Saturday, above the
climatological 90th percentile. Forecast soundings show plenty of
diurnal instability and weak flow through the column. Scattered to
numerous showers and storms are likely Friday afternoon and evening,
with coverage diminishing overnight. Slow-moving, pulse convection
will pose a threat for torrential rainfall, lightning, and
microbursts. Excessive rainfall could lead to localized flooding.
Highs on Friday should reach the upper 80s to near 90 in most
places.

We`ll have a very similar environment in place on Saturday. A
somewhat stronger wave will be rotating southeast across the Great
Lakes by this time, dragging a cold front south through the Upper
Midwest and Great Lakes. A round of scattered, pulse convection
appears likely Saturday afternoon and evening. Outside of these
showers and storms, temperatures are forecast to rise through the
mid/upper 80s during the afternoon hours.


===== Sunday - Tuesday =====

A weak cold front appears likely to drop south into our region by
Sunday. This should be enough forcing interacting with the warm,
humid airmass for at least isolated to scattered showers and storms.

Increasing model spread lowers forecast confidence in the details
heading into next week. However, the general pattern will likely
continue to feature NW flow aloft and a deepening upper level trough
over the eastern US and Canada. A deepening low pressure system will
track east across Ontario Monday into Tuesday, and this system
should drag a somewhat stronger cold front into the Ohio Valley.
This will bring us one more chance for showers and thunderstorms
Monday into Tuesday, before drier air filters in from the northwest
through the middle of next week.

&&

.AVIATION /18Z TAFS THROUGH 00Z THURSDAY/...
Issued at 130 PM EDT Tue Jul 14 2026

High pressure will favor VFR conditions throughout the forecast
period, though clouds around FL025 may result in a brief BKN ceiling
at BWG early this afternoon. In addition, there will be a 10-15%
chance for fog development overnight, mainly at BWG, RGA, and HNB.
Easterly winds around 7-10 kt will ease overnight and return around
3-5 kt from the southeast by the end of the forecast period.

&&

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

&&

$$

SHORT TERM...JRB
LONG TERM...EBW
AVIATION...JRB