813
FXUS63 KLMK 151051
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
651 AM EDT Tue Jul 15 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

* Very warm and humid conditions are expected this week with
  scattered afternoon/evening thunderstorms.  Torrential rainfall,
  gusty winds, and lightning will be the main threats with this
  activity.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 305 AM EDT Tue Jul 15 2025

A weak surface boundary has been slowly lifting northward across the
region this morning.  The boundary currently sits from just south of
French Lick, IN to just south of Louisville and then trails
southeastward to near Richmond, KY.  A weak nocturnal low-level jet
appears to be driving the overnight convection.  Shear is weak
across the region.  However, PWAT values of greater than 2 inches
reside in areas west of I-65.  Between I-65 and I-75 PWATs were in
the 1.8-2 inch range.  Convection has been most focused across
portions of Washington/Mercer/Boyle/Garrard counties this morning.
Locally heavy rainfall of 1-2 inches has been observed via radar
estimates and KY Mesonet observations.  Temperatures remained mild
across the region with readings in the lower-middle 70s.

For the remainder of the overnight, aforementioned boundary should
continue to lift northward across the region.  Two main areas of
convection are likely here.  One will be the ongoing convection
across east-central KY.  This activity should continue to move
eastward toward Richmond and may clip the southern end of the
Lexington metro area later this morning.  Second area of sustained
convection will likely continue across our southwest IN counties of
Crawford/Orange for the next few hours.  Again, severe weather isn`t
anticipated, but locally heavy rainfall will be possible with this
activity.

For today, the overall synoptic environment hasn`t changed all that
much.  Remnant convective complex is forecast to move northeastward
toward the lower Ohio Valley this afternoon.  Combination of this
feature along with plentiful diurnal heating/destabilization is
likely to support convective development across the region.  Deep
layer shear values remain less than 15kts or so through the threat
of organized deep convection looks to be rather limited.  However,
with warm cloud depths of 12-14kft and PWATs over 2 inches, water
loaded storms producing torrential rainfall, gusty winds, and
frequent lightning will be possible.  Highest concentration of
storms looks to be across western KY closer to the remnant MCV
coming into the region.  Storm motions of 15-20 mph are expected and
the main weather hazard today would be localized flooding where slow
moving storms could lay down 1-2 inch amounts in some locations.
Highs on the day will be similar to what we`ve seen in the past few
days with readings in the upper 80s to the very low 90s.

For tonight, we should see ongoing convection from the afternoon
continue into the evening hours.  Remnant MCV across western KY
will continue to move eastward overnight and will be capable of
producing some additional showers/storms into the overnight period.
 severe does not look all that great, but torrential
rainfall, gusty winds, and lightning will be the main hazards with
the overnight activity.  Look for lows in the lower 70s once again.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 305 AM EDT Tue Jul 15 2025

Longer range guidance for mid-week and beyond shows a rather
stagnant upper air pattern across the CONUS.  A short wave trough
axis will move out of the Rockies on Wednesday and into the Plains,
but it does not appear it will be close enough to us to influence
our weather.  In the meantime, look for diurnal instability to
develop leading to scattered showers/storms in the
afternoon/evening.  Highs Wednesday will be in the upper 80s to the
lower 90s with overnight lows in the lower 70s.

By Thursday, the flow aloft continues to look low amplitude with the
upper level ridge over the southeastern US spreading westward with
increasing time.  A rather slow moving frontal boundary looks to
extend from roughly Ohio southwestward back into the southern
Plains.  Current progs do not suggest that this boundary will drop
into our region. However, it will serve as a focus for additional
shower/thunderstorm activity for Thursday.  Model solutions at this
time range continue to have a rather large variance.  We`ll have
ample instability during the afternoon, and with the frontal
boundary close to the region, along with some lowering of the height
field, overall convective coverage on Thursday looks to be a bit
higher than Wednesday.  Shear through this period may be a little
higher as the band of westerlies dips into the region.  Overall
feeling here is that we could have some stronger storms on Thursday
given the slightly better chance of organization.  Gusty winds,
heavy rainfall and lightning would be the main issues here.

For Friday through the weekend and into early next week, the pattern
looks to be potentially unsettled for much of the period.
Sagging/stalled out frontal boundary to the north of the region will
continue to be a focus for repeated rounds of convection.  Will also
have to watch how the upper level ridge to our south evolves over
time.  We`ll have some sort of tropical system that moves across the
northern Gulf on the southern periphery of this ridge axis.  Whether
the moisture gets shunted off to the west toward TX or drawn more
northward into the Ohio Valley remains in question.  Overall,
forecast will keep the same story of very warm and humid conditions
with daily chances of showers/storms.  Again, shear throughout the
column looks to remain fairly weak.  However, plentiful moisture
will be available for storms to produce torrential rainfall, gusty
winds and lightning.  The potential for repeated rounds of storms
may yield a flooding risk across portions of the region, especially
areas that see repeated rainfall each day.  QPF amounts of 2-3
inches through the period look likely, with locally higher amounts
in some spots.  Highs each day will be in the upper 80s to the lower
90s with overnight lows in the low-mid 70s.

&&

.AVIATION /12Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 650 AM EDT Tue Jul 15 2025

Overnight convection has largely diminished over east-central KY.
However, scattered convection continues across far western KY this
morning ahead of an MCV.  Scattered showers down near the BWG area
are likely to diminish as they move northeast.  For the afternoon,
instability build up should lead to scattered showers and storms
across the region.  Generally have this covered with a PROB30 group
for now.  Additional showers/storms are possible overnight as
aforementioned MCV moves eastward across the area.  Look for light
southeast winds this morning become southwest by late morning/early
afternoon.

&&

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

&&

$$

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