LMK issues Area Forecast Discussion (AFD) at Jul 18, 1:51 PM EDT ...Updated Aviation Discussion...284
FXUS63 KLMK 181751
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
151 PM EDT Fri Jul 18 2025
...Updated Aviation Discussion...
.KEY MESSAGES...
* Another day featuring scattered showers and thunderstorms is
expected. Storms could produce gusty winds, torrential rainfall,
and frequent lightning.
* Outside of storms, very warm and humid conditions are expected,
mainly over southern KY where afternoon heat indices may rise into
the upper 90s to near 100 degrees.
* Active weather pattern will continue into the weekend and into
next week with episodic bouts of showers and storms. Hot and
humid weather will continue across the area. A drier pattern may
emerge by mid-late next week.
&&
.UPDATE...
Issued at 1019 AM EDT Fri Jul 18 2025
Conditions are mainly dry at the moment with skies ranging from
partly to mostly cloudy. A bit more clearing is noted across
southern KY, farther from a weak stalled frontal boundary draped
through the Ohio Valley. Temperatures are already warming into the
low to mid 80s in southern KY due to the higher insolation, with
temps still rising through the 70s further north.
It looks fairly quiet through at least Noon, with minimal convective
development expected due to a lack of large scale forcing. However,
isolated to scattered showers and storms should develop by early
afternoon as the very moist airmass continues to heat up and
destabilize. Scattered storms will be most prevalent across central
KY today, where instability and low-level lift will be maximized
along and just south of the effective boundary. Coverage should be
isolated at best further north in southern Indiana.
Forcing aloft is nonexistent today, with weak height rises during
the afternoon hours. Mid-level westerly flow remains quite weak at
around 20 kt. Isolated strong pulse storms will be possible with
MLCAPE likely exceeding 2000 J/kg across much of central KY. Steeper
low-level lapse rates and water-loaded downdrafts could result in
localized downbursts. The other concern will be localized heavy
rainfall, but the flash flood threat is lower than yesterday. Still,
will need to keep a very close eye on our KY counties along and just
south of I-64. These areas have received a significant amount of
rainfall recently, resulting in much lower Flash Flood Guidance.
Issued at 653 AM EDT Fri Jul 18 2025
Did a quick update to drop the flood watch as widespread flood
threat has diminished across the region. Scattered showers/storms
will move across the northern Bluegrass region this morning and may
produce some locally heavy rainfall in spots. A trailing line of
showers and a few storms will move along the WK/BG Parkway corridor
through about mid-morning. Have increased PoPs across these areas
with this quick update.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 333 AM EDT Fri Jul 18 2025
Partly to mostly cloudy skies were noted across the region this
morning with temperatures in the lower to middle 70s. Area radars
showed ongoing shower and thunderstorm activity across southwest
Indiana and into portions of west-central Kentucky. This activity
was being driven by a weakening MCV that is moving out of southern
IL. Activity remains below severe limits, and it is not expected to
strengthen during the overnight hours. Plentiful moisture was in
place across the region with PWATs remaining in the 1.9-2.2 inch
range. Showers and storms this morning will continue to move to the
northeast and will be capable of producing torrential rainfall,
gusty winds, and frequent lightning. So far, most of this activity
has been producing QPF amounts of 0.25 to 0.75 inches. The main
convection this morning has been transversing areas that saw lesser
rain amounts than Thursday afternoon. However, will be carefully
monitoring storms coming out of southwest IN that look to move
through southern IN this morning where FFG values are lower. The
flood watch will remain in effect across southern IN and portions of
north-central and east-central KY thorugh 700 AM EDT.
Moving into the daytime hours, partly to mostly skies are expected.
Cloud cover looks to be a bit more significant today and overall
insolation may be a bit less than we've seen in the past few days.
Afternoon highs will warm into the mid-upper 80s with perhaps a few
spots down across southern KY warming to around 90. Isolated to
scattered thunderstorms will likely develop in the mid-late
afternoon time frame. The forcing across the region continues to
feature moderate instability but very weak shear. So the overall
convective scheme today will be similar to the last few days with
mainly pulse type convection with an attendant heavy rainfall, gusty
wind, and lightning threat. The main axis of storms today may set
up a little further south of where heavier rainfall fell on
Thursday. Current progs suggest thunderstorms will mainly be
focused along and south of the WK/BG Parkways. Rainfall rates of 1-
2 in/hr will be possible so areas could pick up a quick 1-2 inches
with some locally higher amounts. Given that this rainfall is
expected to fall over area with a higher FFG threshold, an extension
of the flood watch is not expected with this forecast.
For tonight, ongoing afternoon and evening convection will persist
into the late night hours before diminishing. A resurgence of
convection may develop over western KY late tonight as another MCV
rolls into the region. Lows will be in the lower-middle 70s.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 333 AM EDT Fri Jul 18 2025
For the weekend and into next week, the overall forecast thinking
has not changed much. An upper level ridge will remain over the
southeastern US with our region residing along a baroclinic zone.
We'll remain on the warm/humid side of this boundary through the
weekend. An extremely moist airmass will remain in place across the
region with PWATs remaining above 2 inches which is well above
climatological values.
Episodic bouts of convection are expected as upper level
perturbations and remnant MCVs from ongoing convection roll through
the region. One of these MCVs looks to move through the region
during the day on Saturday. While adequate instability will be in
place across the region, the faster belt of westerlies will remain
to our north resulting in rather marginal shear values for organized
severe convection across the region. As seen in the past several
days, strong storms will be possible in the afternoon/evening with
gusty winds, torrential rainfall, and lightning being the main
threats. A corridor of heavy rainfall may set up from central IL
into central/southern IN and into SW Ohio and eastern KY. As this
heavy rainfall corridor becomes clearer, a flood watch may be
required for portions of the LMK forecast area on Saturday.
As we move into Sunday, the upper level ridge looks to retrograde
slightly to the west with heights building across the Plains. This
will allow our upper level flow pattern to become increasingly more
northwesterly with time. The overall baroclinic zone will shift
from a zonal type regime to a northwest-southeast oriented one from
the Midwest down into the eastern Ohio Valley. With our region
remaining on the periphery of the southeast ridge, we'll have to
watch for more MCVs and perturbations that will bring clusters of
showers/storms to the region mainly in the Sunday through Tuesday
period. Storms during the period may be strong to marginally severe
with mainly a wind damage threat due to waterloaded downdrafts. The
storms will also be capable of torrential rainfall and the repeated
nature of heavy rainfall potentially training over the same areas
may result in an enhanced flood risk across portions of the region.
Daytime highs will be in the mid-upper 80s to near 90 with overnight
lows in the lower-middle 70s.
By Wednesday of next week, there continues to be an increase in
forecast confidence that the mid-level ridge will start to expand
and shift the storm track away from the region. While that will be
good news in getting the heavy rainfall potential out of the region,
it will also result in an increase in temperatures with no relenting
of the humidity. Highs by mid-late next week will warm daily into
the upper 80s and into the lower 90s. Given that we'll have
plentiful moisture in the ground and in the air, dewpoints will
remain in the lower-middle 70s resulting in afternoon heat indices
warming well above 100 degrees by mid-late next week.
&&
.AVIATION /18Z TAFS THROUGH 00Z SUNDAY/...
Issued at 150 PM EDT Fri Jul 18 2025
BKN MVFR stratus is finally lifting and trying to SCT out a bit.
Prevailing VFR is likely after 18-19Z outside of thunderstorms with
light winds. SCT TSRA will continue through the evening, especially
across the southern half of central KY. BWG and RGA are most likely
to see brief TSRA impacts, including IFR vis, brief torrential
rainfall, gusty winds, and frequent lightning.
Convective activity will weaken and become more isolated after
sunset this evening. Some shower and isolated TSRA activity looks
possible at HNB and SDF early Saturday morning, but the greatest
TSRA chances will come late Saturday morning through the afternoon
hours. Another round of MVFR clouds looks possible mid to late Sat
morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATE...MJ/EBW
SHORT TERM...MJ
LONG TERM...MJ
AVIATION...EBW
Source:
LMK issues Area Forecast Discussion (AFD) at Jul 18, 1:51 PM EDT ...Updated Aviation Discussion...---------------
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