269
FXUS63 KLMK 261851
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
251 PM EDT Sat Apr 26 2025

.KEY MESSAGES...

*  Dry conditions expected through Monday.

*  A cold front will bring storms to the region Tuesday evening and
   night. Some strong to severe storms will be possible.

*  Showers and thunderstorms will continue into Wednesday and
   Thursday as Tuesday`s cold front stalls over the area. Localized
   flooding will be possible under stronger storms, especially
   Thursday. A severe threat may also develop with later Thursday
   storms.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 250 PM EDT Sat Apr 26 2025

Low level high pressure has begun to build in across the region in
the wake of departing cold front as low stratus continues to linger
across portions of Bluegrass. KY Mesonet obs show temperatures as of
1430L EDT reaching near 70 across the KY/TN border while areas under
cloud cover have struggled to reach the mid 50s. GOES-16 satellite
continues to show slow dissipation of the stratus layer, so still
expecting clearing skies by this evening.

Surface high pressure will slowly traverse across the Great Lakes
and OH Valley tomorrow reaching a zenith of around 1025mb. Expect
dry conditions with easterly winds tomorrow, though upstream
convective debris will result in increasing cirrus resulting in
filtered sunshine. Lows Sunday morning will bottom out in the 40s
with afternoon highs reaching into the mid 60s, several degrees
below climatological norms.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 250 PM EDT Sat Apr 26 2025

Sunday Night - Monday...

The long term period will begin with surface high pressure and
ridging aloft bringing dry and quiet weather. Overnight lows will be
in the mid-upper 50s and highs in the low-mid 80s. High pressure
will shift east of the region, allowing southerly flow to usher in
moisture. Dew points should raise from the mid 40s to the low 60s on
Monday.

Deep troughing over the western CONUS will translate northeast
developing a low pressure system over the northern Plains. The warm
front associated with this system will approach the region Monday
evening, bringing a small chance for PoPs.

Monday Night - Friday...

The low pressure system will move through the northern Great Lakes
and eastern Canada bringing a cold front south through the lower OH
Valley on Wednesday.

Strong ridging over the eastern CONUS will begin to degrade as
troughing over southern Canada swings through. The lower OH Valley
is in a tricky spot on Tuesday, as it is between the two features.
Some guidance and cluster analysis suggests that the ridge will hold
over the region and some guidance shows ridging sinking south.
Either way, decaying convection will approach the region from the
northwest. Better forcing will likely remain to the north of the
region with the trough and upper jet. The LLJ may just brush
southern Indiana. Forecast soundings show 25-30kts of effective
shear and ample instability on Tuesday afternoon. However, storms
seem to approach the region in the evening when instability is
waning. There is enough evidence to warrant a concern for severe
storms over northern Kentucky and southern Indiana Tuesday evening
and into the overnight, however, this is conditional on the timing
and the strength of the riding overhead.

As the cold front moves through the region, it will begin to slow
and stall. What happens on Tuesday night will determine the outcome
of Wednesday. If the ridging holds and the cold front slows just
north of the region, there will less of a concern for flooding and
potential severe storms. If ridging sinks south and storms move
through Tuesday night, there will be a chance for continued showers
and storms on Wednesday along the stalled front.

Later in the week, a system out of the southern Plains will lift the
stalled front north as a warm front. The low will likely track to
the northwest of the region, bringing another cold front southeast
at the end of the week. With southern wave may phase with a northern
wave over southern Canada. This would bring another potential for
strong to severe storms Thursday into Friday. With the upper and
lower level features tracking closer to the region, this raises a
larger concern than the mid week threat, given forcing proximity.
The increased shear would also increase the tornado threat.

With multiple rounds of showers and storms, flooding will be
possible.

Saturday (Derby Day)...

The previous features may push out of the region, and high pressure
will build in behind. This will lead to dry and mild conditions.

&&

.AVIATION /18Z TAFS THROUGH 00Z MONDAY/...
Issued at 250 PM EDT Sat Apr 26 2025

The cold front has now pushed east of KY as low stratus continues to
cover portions of the region. Expect to see MVFR CIGs break up and
give way to VFR conditions by late afternoon, hanging on longest at
LEX and RGA. NW-Nrly winds will continue at a clip of around 10kt
until sunset, upon which direction will veer to NE and slacken to
under 5kts overnight. VFR conditions will continue through the end
of the TAF cycle, with increasing high clouds ahead of a
strengthening system out west. Winds will pick up Sunday mid morning
out of the E at around 10kt.

&&

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

&&

$$

SHORT TERM...CG
LONG TERM...SRW
AVIATION...CG