704
FXUS63 KLMK 162307
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
Issued by National Weather Service Kansas City/Pleasant Hill MO
707 PM EDT Fri May 16 2025

.KEY MESSAGES...

*  SIGNIFICANT SEVERE WEATHER OUTBREAK POSSIBLE LATE THIS AFTERNOON
   INTO THIS EVENING.

*  All severe weather hazards are on the table, including damaging
   winds, large hail, tornadoes, and torrential rainfall. A few
   strong tornadoes and instances of very large hail are possible.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 443 PM EDT Fri May 16 2025

A significant severe weather outbreak is forecast across the western
Ohio Valley this afternoon and tonight.  Currently across our
region, earlier clouds and rain have moved out and we`ve begun to
heat up.  Temperatures were generally in the upper 70s to the lower
80s across the region with the urban heat island in the lower 80s.
Satellite imagery shows where buoyancy is located, which is just
south of the I-64 corridor where the cloud field clearly shows
horizontal convective rolls indicative of strong deep layer shear.

ACARS soundings out of SDF show that CINH is just about eliminated
while BNA is free and clear of any capping.  We`ve seen some
convection try to fire down in the Lake Cumberland area.  This is in
area of localized surface mass convergence.  An outflow boundary
from previous convection extending east into JKL`s area will likely
continue to wash out with time.  Convection down there has continued
to struggle.  There appears to be a boundary extending from roughly
Somerset northwestward to about Owensboro.  Latest WoFS runs along
with the operational HRRR suggest that some isolated-scattered
convection may try and get going along that boundary.  If so, model
proximity soundings would suggest supercellular development posing
an all hazard risk.

The main severe weather risk will come later this evening as an
impressive band of supercells across western IL and eastern MO works
eastward into southern IN and western KY.  We`re still seeing a bit
of variance in trying to time this stuff through the region.  So for
this update, it appears that this activity would move into our
western area by early evening and then into the I-65 corridor by mid-
evening.  This activity could surge a bit more as the cold pool gets
more established and it can get into the Bluegrass/Lexington area by
mid-late evening.  This line will be capable of producing damaging
swaths of wind.  Wind gusts of 65-75 mph will be possible with this
line, especially in the apex of the surges.  QLCS tornadoes are
likely as well as the low-level jet axis will increase across the
region this evening resulting in very favorable hodographs.  Large
hail will be possible within the squall line as well.  However, the
larger hail will be more confined to any discrete supercell.
Plentiful CAPE in the 0-15C layer and steep low-mid level lapse
rates suggests that 1-2.5 inch hail could occur.

Later tonight, there is a possibility that the squall line could
become more east-west oriented down across southern KY.  If this
were to occur, training of heavy convection would occur resulting in
an increased flood risk.  Given the rainfall this morning and the
possibility of this scenario playing out, a Flash Flood Watch was
issued earlier today to cover this threat.  Most of the convective
activity with the line should exit our area in the 1-2 AM EDT time
frame.

Bottom line, significant severe weather is possible late this
afternoon and this evening. Make sure you have multiple ways to
receive warnings and a plan in place should a warning be issued!

Drier, cooler and less humid weather is expected for Saturday with
highs in the lower-mid 70s over southern IN and upper 70s to lower
80s down across southern KY.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 443 PM EDT Fri May 16 2025

Saturday Night through Monday Night...

Dry conditions are expected Saturday night with lows in the upper
50s to around 60.  For Sunday, we`ll see some weak ridging build in
from the west.  A low-level flow will allow for some moisture return
across western and southern KY could result in some scattered
showers.  Highs on Sunday will be in the upper 70s with a few 80s
down across southern KY.  By Sunday night, upper level ridging will
build slightly more northward into the region.   A warm frontal
boundary is expected to lift northward through the region bringing
additional showers and storms to the region.  Lows Sunday night will
be in the upper 50s north of the front, but south of the front
overnight lows will be in the low-mid 60s.

By Monday and into Monday night, the warm front is likely to stall
out across the region with areas of showers and storms.  Model
soundings do show some instability and adequate shear for organized
storms. Though, the best shear/instability remains well west of our
region. ML guidance agrees with this, but does have some low
probabilities out in our western area.  Highs will range from the
mid-upper 70s over the Bluegrass to the lower 80s over the southwest
area.   Lows Monday night will be in the 60s.

Tuesday through Friday...

Upper level low over the northern Plains will get into a Rex block
type pattern by late Tuesday and into Wednesday.  Aforementioned
warm front will remain in our region and will serve as a focus for
additional shower and thunderstorm development.   Some strong/severe
storms are possible as the low and frontal boundary pass through the
region.  Highs Tuesday will be in the upper 70s to the lower 80s
with overnight lows in the upper 50s/lower 60s.  Highs Wednesday
look to be cooler with readings in the upper 60s to lower 70s.

Upper low looks to move from the Midwest into the Great Lakes region
by Thursday with the Ohio Valley remaining in a cool cyclonic flow.
We`ll likely need to keep some scattered showers in at least for
Thursday with drier weather for Friday.  Highs both days will be in
the upper 60s to the lower 70s with overnight lows in the upper 40s
to the lower 50s.

&&

.AVIATION /00Z TAFS THROUGH 06Z SUNDAY/
... Issued at 707 PM EDT Fri May 16 2025

The primary concern for this issuance is the timing into each
terminal of convection and the then the timing of the exiting in
the southeast portion of the area tonight. A couple areas of
concern initially. 1) The supercell in southern KY is tracking
east, right toward KBWG. Timing the leading edge of this cell
into that terminal gives an arrival time of 00Z. Going forecast
had this depicted but have refined the timing of this cell to
move east of KBWG by 02Z. It looks like there could be a lull in
activity at this site the 2) the main line moves through the
area overnight. It looks like the scattered supercells
developing along the front will merge/ develop into a line of
storms that tracks through the entire area. So have tried to
time the front through which ends convection from 03Z to 06-07Z.


&&

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

&&

$$

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