197
FXUS63 KLMK 141058
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
658 AM EDT Sat Jun 14 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

*  Scattered showers and thunderstorms are expected over the
   weekend, mainly during the afternoon and evening hours. The
   potential for severe storms is low, but additional swaths of
   heavy rain would increase the risk for localized flash flooding.

*  Unsettled weather continues next week, with continued rounds of
   afternoon and evening showers and storms expected.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 331 AM EDT Sat Jun 14 2025

Early this morning, the coverage of rain showers has diminished
across central KY and southern IN with the loss of daytime heating.
Mild temperatures in the upper 60s and lower 70s are noted as of
06Z; temperatures should remain fairly steady through the pre-dawn
hours as scattered clouds and light southerly winds hinder nighttime
cooling.

A vertically-stacked low pressure system is currently passing near
St. Louis and will gradually work across southern IL this morning.
While PW values are high across the region, two relative maxima are
noted on current mesoanalysis, supported by short term progs: one
extending from central AR northeast into western KY, and another
north of the I-70 corridor across central IL and IN. As the low
pushes to the east today, the PW maxima southwest of the area will
move over central KY, while the PW maxima north of the area may try
to creep toward southern IN. As a result, PW values will be around
or just under 2" across the CWA today, with SW low-level winds
continuing to pump moist air into the region. Once daytime heating
returns later this morning, coverage of rain showers should
increase, with scattered showers and a few thunderstorms continuing
through the afternoon and into the evening. Temperatures should top
out in the upper 70s and lower 80s this afternoon.

Given the increased moisture within the column, coverage may be
greater today than on Friday. On the other hand, with the center of
the low pressure system closer to the area today, flow aloft will be
weakening, resulting in weaker deep-layer shear and more random
convective development. Also, given the increasing low cloud cover
across the area, low-level lapse rates may not be as steep, with
MLCAPE more on the order of 500-1000 J/kg and CAPE profiles which
should be unfavorable for strong updrafts. Would expect less in the
way of lightning this afternoon, though isolated to scattered storms
are still expected. All in all, storms which develop should mainly
be garden-variety, with brief heavy downpours and gusty winds in the
strongest cores. The main concern with any heavier storms would be
for heavy rainfall amounts and isolated flooding. Along and south of
the KY Parkways, mean cloud layer winds should remain between 15-25
kt out of the WSW, so residence time of individual storms shouldn`t
be too great. However, coverage should be greater in the south, and
there are a few swaths of 2-3" of rain on the 00Z HREF localized
probability-matched mean. North of the Ohio River, storm motions may
slow to less than 10 mph late this afternoon as the upper low moves
overhead. Fortunately, coverage should be lower; however, we`ll
still have to watch for isolated flash flooding in any heavier cells.

By tonight, the upper low will have opened up and begun to weaken as
it lingers near the Ohio River. After sunset, rain coverage should
decrease quickly, with only isolated showers continuing overnight.
Another mild and humid night is expected, with lows only falling
into the upper 60s and lower 70s Sunday morning.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 331 AM EDT Sat Jun 14 2025

Sunday and Monday...

What is left of the upper disturbance and the associated sfc low
will push across eastern KY and into the central Appalachians Sunday
into Sunday night. While lower PW values will try to work into the
area from the NW, the majority of guidance keeps the humid air mass
in place, resulting in another day of summertime showers and storms,
though coverage should be greatest east of the I-65 corridor. We
should be able to see more sunshine on Sunday, which should allow
temperatures to warm into the low-to-mid 80s.

After another mild and mostly dry night Sunday night, confidence is
increasing that Monday will bring another chance for scattered
showers and storms. Guidance earlier this week had ridging over the
southwest US trying to spread east on Monday; however, now it looks
like another subtle upper disturbance may meander into the region on
Monday, with the humid, unstable air mass remaining in place.
Temperatures may warm a few degrees given more sunshine, with highs
mainly in the mid 80s across the area.

The Rest of Next Week...

From Tuesday through Thursday, the upper-level pattern across North
America should become fairly zonal. Multiple shortwave disturbances
are expected to quickly translate eastward within this zonal flow
pattern, bringing waves of greater precipitation coverage, and
potentially chances for a few stronger storms as they pass. For the
most part, a continued humid and seasonably warm air mass will bring
recurring chances for scattered afternoon and evening showers and
thunderstorms. We will have to monitor what should be the most
substantial of the systems for next week, which should cross the
Ohio Valley Wednesday evening into Thursday morning. There are
modest signals in ECMWF AI/ML severe guidance for a wave of stronger
storms, though this would be somewhat dependent on whether timing is
synchronized with the diurnal maximum in heating/instability.

By the end of the week, medium-range guidance is in relatively good
agreement about the synoptic pattern, showing amplification of the
upper-level wave as troughing digs along the west coast and ridging
builds across the eastern CONUS. Assuming perfect prog, this should
suppress the chances for showers and storms, and right now, the
forecast only calls for isolated storms, though this could be
overdone if confidence increases further. Additionally, this pattern
change would lead to warming temperatures across the region as we
head into next weekend, likely bringing widespread upper 80s and low
90s into play.

&&

.AVIATION /12Z TAFS THROUGH 18Z SUNDAY/...
Issued at 657 AM EDT Sat Jun 14 2025

This morning, the main impacts to operations will be from
MVFR/possible IFR stratus which has moved from west to east across
HNB, SDF, and BWG and will approach LEX and RGA. Reduced ceilings
should hang around until 15-18Z before gradually beginning to lift
and return to VFR conditions. Today, scattered showers and a few
thunderstorms will move across the region. Confidence in timing is
relatively low, but any heavier shower which develops could bring
TEMPO IFR/MVFR visibilities. Winds will be out of the S/SW for much
of the day, generally between 6-10 kt. After sunset this evening,
the coverage of showers should diminish, with VFR conditions
expected in general through the evening and early overnight hours.
However, toward the end of the current forecast period, moisture is
expected to build down, potentially bringing another window for
IFR/MVFR ceilings and visibilities Sunday morning. Confidence in
this is low-medium at this time.

&&

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

&&

$$

SHORT TERM...CSG
LONG TERM...CSG
AVIATION...CSG