137
FXUS63 KLMK 101855
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
255 PM EDT Thu Sep 10 2026

.KEY MESSAGES...

* Surface cold front to push southward through the region tonight
  and Friday.  Waves of showers and thunderstorms are expected with
  widespread rainfall amounts of 0.5-1".  Localized higher amounts
  of 1.5-2.5" will be possible and could result in some isolated
  flooding concerns.

* Unsettled weather is likely into the day on Saturday with drier
  conditions arriving by Sunday.

* Overall drier and hotter conditions arrive early next week.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 255 PM EDT Thu Sep 10 2026

Mid-afternoon satellite imagery reveals mostly cloudy skies across
southern IN an the northern half of KY.  Partly cloudy skies were
noted across southern KY, south of the WK/BG Parkway corridor. Under
the clouds, temps have been held down into the mid 70s.  Where the
clouds have been less sparse, temps have warmed into the lower-
middle 80s.  The warmest locations are in our southwest across the
WABBLES area where readings were in the mid-upper 80s.

For the remainder of the afternoon period, widespread cloudiness
across southern IN and northern KY has kept temps down as well as
instability.  A cold front to the north of the CWA will continue to
sag southward slowly this afternoon and evening.  Further south,
where clouds have been more sparse, significant warming has occurred,
mainly south of the WK/BG Parkways.  In this region MLCAPE values
will likely continue to surge into the 1500-2000 J/kg range.  Shear
is weaker over this area, as the low-level jet axis has pushed
further off to the east.  Through the afternoon, the most
concentrated area of showers/storms will be in the area bounded by
the WK Parkway in the north and generally west of the I-65 corridor.
Upstream shortwave trough axis will swing through the region
yielding the necessary forcing for convection. The overall severe
threat looks low across the region despite ample instability.
However, while low-level lapse rates are decent enough (>7 C/km),
mid-level lapse rates are pretty anemic around 5.5 C/km. Any
stronger core may become precipitation loaded with wet microbursts
and isolated gusty winds being the main hazard.  PWATs in this
corridor are up around 2.1-2.2 inches so localized heavy rainfall
will be possible.  Some minor hydro issues could develop in areas
that see repeated and/or training of rainfall.  The highest risk of
training of storms looks to be just south of the WK/BG Parkways.

For tonight, we expect the aforementioned frontal boundary to
continue southward through the region.  Convection from the
afternoon/evening should diminish with time and loss of daytime
heating, however scattered convection will likely persist into the
overnight hours.  A secondary area of showers/storms may develop
across southeast IN and into far northern KY overnight, yielding a
swath of heavier rainfall.  For the late overnight, areas of
mist/fog will be possible with overnight lows in the upper 60s to
around 70 in most locations.

For Friday/Friday Night, aforementioned frontal boundary will likely
washout across the region.  We`ll likely start off the day with
mostly cloudy conditions with some improvement during the afternoon.
Another batch of convection may develop over far southwest KY and
northwest TN in the afternoon and track across southern KY in the
late afternoon/evening.  Some strong storms can`t be ruled out with
this activity and gusty winds/lightning would be the main threats.
Went a little below NBM here for highs and closer to the HREF mean.
Highs in the afternoon will likely top out in the lower 80s across
southern IN and northern KY with mid-upper 80s down across southern
KY.  Scattered convection will likely continue into Friday night,
mainly across our southeastern quarter with lows in the upper 60s to
around 70.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 255 PM EDT Thu Sep 10 2026

Saturday/Saturday Night...

Weak surface boundary is likely to be in the vicinity of the KY/TN
border region Saturday morning and will likely drift northward
slightly during the day.  Aloft, another upper level shortwave axis
will pivot through the region and likely result in another round of
showers and storms across the region.   Model soundings show
tall/skinny CAPE profiles with weak shear and a high PWAT airmass in
place.  So slow moving showers/storms with heavy rainfall and gusty
winds looks likely for Saturday.  Highs on the day should top out in
the 82-87 degree range with overnight lows in the upper 60s to
around 70.

Sunday through Thursday...

By Sunday, upper trough axis is forecast to shift to our east.
Strong mid-level ridging will build into the region from the west
and a period of dry weather with above normal temperatures are
expected.  Highs of 85-90 are expected for Sunday and Monday before
warming into the 87-92 degree range by Tuesday and Wednesday.
Earlier 10/00Z guidance suite suggested the ridge breaking down by
mid-week.  However, latest Euro Op/Ensembles are a bit slower with
this potential breakdown holding on to the ridge into Thursday.  If
the ridge were to break down and we get a front into the region,
highs would back off into the upper 80s.  However, a slower solution
would result in a delay and highs on Thursday could remain in the
lower 90s.

Extended Forecast Discussion...

The month of September is off to a hot start.  Thus far we`re
running about +8.5F above normal at SDF, +8.6F at BWG, and +7.6F at
LEX.  We`re likely to keep those above average temperatures going
due to the expected warm period of weather for much of next week.

Looking at the hemispheric scale, we`re starting to see some
interesting changes on the horizon.  Quite a few of the extended
models and ensembles are indicating a cool down for our area as we
enter late September, probably after the 20th or so.  The forcing
mechanism behind that appears to be a combination of factors that
may come together.  The Euro and its ensembles have been fairly
intent on developing a strong area of high pressure over western
Asia just north of the Himalayas.  If this occurs, we`ll get a
strong pressure gradient there which will result in a good amount of
momentum transfer into the atmosphere.  Global atmospheric angular
momentum charts really ramp up over the next 2 weeks and this should
lead to a Asian jet enhancement and eventually a Pacific jet
extension and enhancement.  The downstream affects here would lead
to a stronger ridge over AK and a +PNA pattern.  Downstream, decent
troughing looks to develop across the eastern CONUS.  Interestingly
enough, the west Pacific looks to be favorable for continued typhoon
activity and we`ll be watching for any typhoons that recurve and
merge into the Pacific Jet which could yield stronger impacts to the
flow over the CONUS later this month. Considerable uncertainty
remains as to how much the pattern will flex, but confidence is
increasing that seasonal fall air will be possible across our area
for late September into October.

&&

.AVIATION /18Z TAFS THROUGH 00Z SATURDAY/...
Issued at 203 PM EDT Thu Sep 10 2026

Showers continue to move through southern Indiana, with scattered
thunderstorms starting to pop up across south-central Kentucky.
These storms should be individually short-lived, but will continue
to spawn across the southern portion of Kentucky. Winds shift from
northwesterly to a weak variable/northeasterly overnight, with
any gusts associated with a passing shower. Patchy fog sets in in
the morning alongside low CIGs, especially in places that received
moderate rainfall in the past day, with HNB/RGA/LEX in IFR
visibilities. CIGs across the whole area should remain VFR outside
of passing storms until this evening, when the whole area settles
into likely MVFR clouds before letting up tomorrow mid-morning.

&&

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

&&

$$

SHORT TERM...MJ
LONG TERM....MJ
AVIATION....JPH