481
FXUS63 KLMK 040620
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
220 AM EDT Sat Oct 4 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

*  Chance for an isolated slow-moving shower mainly along and north
   of I-64 through the evening hours. A few rumbles of thunder can`t
   be ruled out.

*  Dry and warm weather continue for most through this weekend.

*  Rain chances increase early next week ahead of a cold front
   arriving on Wednesday.

&&

.UPDATE...
Issued at 642 PM EDT Fri Oct 3 2025

The cluster of showers and storms which meandered across portions of
Washington, Floyd, Scott, Clark, and Harrison County Indiana has
finally collapsed over the past 30 minutes. It appears that the area
of convection ultimately ran out of real estate where there was a
greater pool of available instability. Latest SDF ACARS sounding
profiles suggest that it will take quite a bit of mechanical lifting
to get parcels to their LFC, which is around 825 mb. While lingering
outflow boundaries could provide that forcing, diminishing coverage
of cu suggests that surface-based convective processes are wrapping
up for the day. As a result, will carry a slight chance PoP through
00Z, but then carry a dry forecast thereafter.

The only corridor where there is lingering evidence of agitated cu
is from Jefferson County, IN down to the Louisville metro, so if any
additional showers were to develop, this corridor would be favored.

&&

.SHORT TERM /THROUGH SUNDAY/...
Issued at 306 PM EDT Fri Oct 3 2025

Still hanging onto a few chain reaction showers across our NW CWA at
this hour, and expect this process to continue through the late
afternoon and into the evening where the combination of the highest
PWATs (1.2 to 1.3") overlap with a meager instability (500 J/KG of
ML CAPE) axis. As a result, the focus currently across our NW CWA
will likely shift to our north central CWA by early evening. Hi-res
models have latched onto isolated to widely scattered coverage of
showers and a few ticks of lightning for areas N and NE of the
Louisville metro for the evening, so will carry some 20-30% chances
there.

It is worth noting that shower motion will be quite slow and
erratic given the weak vertical wind profiles, so localized areas
could pick up decent amounts of rainfall where it does rain.
Overall, basin average QPF will remain quite low as you would
expect, but a very isolated amount of 1" could occur for a spot that
sees repeated or slow moving activity. Just as an example of this
environment`s potential, HREF LPMM QPF values peak over 1" in rural
Washington county IN. While the placement may not be perfect, the
potential for somewhere across our north central CWA to see amounts
that high seems possible.

Overall, tough call on whether to allow any thunder mention as the
vertical depth of convection will be confined between a high LFC,
and mid level inversion. This will put storm depth around 10 k feet.
We have seen a few in-cloud pulses, so will probably carry a slight
chance mention of T to go along with mainly shower mention. Will
also mention that this type of cold core H5 pattern could allow for
a few cold air funnels or a brief landspout to form. SPC
Mesoanalysis does indicate there is some non-supercell tornado/low
level stretching potential with this environment, and these
parameters do look to line up with our best instability axis this
afternoon, mainly north and east of the Louisville Metro. Something
to watch.

Moving into tonight, any lingering convection should diminish with
mostly clear and calm conditions taking hold. Good radiational
cooling, and higher Tds than recent nights could allow for some fog
potential, especially across our eastern CWA.

The upper ridge axis remains in control tomorrow, and we`ll see
continued warm as well as dry conditions. Temps look to peak in the
mid 80s, which continues to be well above normal for this time of
year.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Issued at 306 PM EDT Fri Oct 3 2025

The Rest Of The Weekend...

The upper ridge axis and surface high pressure continue to slide
eastward through through the late weekend, settling along the East
Coast. This feature will still have enough influence on our area to
keep us warm and dry. Look for above normal temperatures peaking in
the mid to upper 80s each day, with comfortable lows mostly in the
50s. We get some moisture return by Sunday night, so may see
slightly milder lows by Monday AM in the upper 50s and low 60s.

Monday - Friday...

Monday will be a transition day from an upper pattern standpoint as
the upper ridge loses influence over our area and the digging north
central CONUS trough begins to win out. We`ll see Gulf moisture
return on the western side of the retreating upper ridge, adding
deeper moisture (higher PWATs) into our area. In addition, some
subtle low level jetting begins to respond beneath an increasing mid
and upper level wind profile. As a result, we could start to see
some isolated to scattered shower or storm activity across the area,
especially the deeper into Monday or Monday evening we get. Tuesday
looks to be the highest coverage day of showers and storms, which is
a slightly faster trend from yesterday`s data. By this time, the
surface cold front will be approaching along with the upper trough
axis and higher degree of forcing/low level moisture transport.

Given the faster trend, the Wednesday time frame looks cooler/drier
with a clean cold frontal passage along with the upper trough axis
swinging through. Surface high pressure begins to build in through
late week, which should return us to dry conditions. The biggest
change looks to be the cooler temperatures with highs only in the
low to mid 70s for Thur/Fri, and some lows in the 40s and 50s each
morning.

&&

.AVIATION /06Z TAFS THROUGH 12Z SUNDAY/...
Issued at 218 AM EDT Sat Oct 4 2025

With upper ridging and surface high pressure still in place, a
mostly VFR forecast is expected, but with some earlier showers at
HNB and some guidance of light fog in the east at LEX and RGA,
limited fogging can`t be ruled out. Winds continue to be light with
mostly clear skies.

&&

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

&&

$$

UPDATE...CSG
SHORT TERM...BJS
LONG TERM...BJS
AVIATION...KDW