314
FXUS63 KLMK 150122
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
922 PM EDT Tue May 14 2024

.KEY MESSAGES...

*   Active pattern with many chances of showers and storms through
    Wednesday.

*   A strong storm or two may be possible this afternoon and
    evening. The best chances for a severe storm or two will be
    south of I-64 and west of I-65.

*   The most likely period for dry weather is Wednesday night
    through Thursday afternoon.

*   Another storm system will increase rain/storm chances for the
    end of the week and into the weekend.

&&

.UPDATE...
Issued at 922 PM EDT Tue May 14 2024

Scattered showers and storms have remained mostly west of I-65 so
far this evening, but the cluster over south-central Kentucky is now
moving closer the the Lake Cumberland area. A few storms this
evening have had some broad rotation aloft, but besides that it has
been a hydro-focus with minor flooding issues. With the upper low
located over central IL this evening, the associated sfc low is
centered over the Wabash Valley, keeping additional shower and storm
activity going across mainly western KY and southwestern IN.
However, the severe threat is quickly diminishing with instability
waning and hardly any wind shear to speak of. Leftover storms are
mainly unorganized this evening.

Overall forecast remains in good shape, and no changes are planned
at this time. Best precip chances will shift to our east-northeast
sections for the forecast area overnight, leaving the south-central
KY counties dry for most of the night. Additional showers and storms
will swing down into the area again tomorrow as the low pressure
system sits nearby.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 319 PM EDT Tue May 14 2024

As of 3 PM EDT, RAP 500 MB analysis and water vapor imagery showed a
positively tilted trough of low pressure moving through Missouri
into western Kentucky with pelnty of moisture ahead of the system
throughout the central portions of KY and south-central Indiana.
Radar observation showed several areas of scattered showers with
embedded thunderstorms across the region with moderate rainfall at
times. Overcast skies with temperatures in the mid 60s to lower 70s
were present across the forecast area.

The latest high resolution model guidance has scattered showers and
thunderstorms continuing this afternoon and evening for much of the
area (with a few short breaks inbetween).  Model soundings this
afternoon/evening have the "long skinny CAPE" look with SBCAPE
around 1200+J/KG, but effective layer CAPE values sub 1000 J/KG
leaves something to be desired for widespread strong thunderstorms.
While the area is outlooked for a marginal (level 1 of 5) chance for
a severe thunderstorm with a small tornado probability, the
widespread overcast skies, lack of wind shear aloft, and showers
already in progress will likely limit widespread severe potential.
While we cannot rule out a strong storm or two west of I-65 & south
of I-64  in areas where there`s more clearing and instability, much
of today will be a rainy and dreary day with a small chance of minor
flooding in poor drainage and low lying areas.


Precipitation amounts will vary from one location to the next due to
the convective nature of the rainfall, but half an inch to an inch
is a good ballpark number for southern Indiana and central Kentucky
through Wednesday.  Lows tonight will be around 60 with afternoon
high temperatures in the lower 70s again Wednesday with mostly
cloudy skies.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 319 PM EDT Tue May 14 2024

Wednesday night into Thursday morning will feature the sfc low and
associated upper trough located off the Mid-Atlantic coast as upper
ridging and a weak area of sfc high pressure build in over the Ohio
Valley behind it. This will provide a brief period of dry weather
late Wednesday morning through most of the day on Thursday. While
not completely clear, there will be enough solar energy to warm
temperatures into the upper 70s to low 80s.

Our break from the active wet weather will be short lived starting
Thursday night into the start of the week. Overall confidence drop
for the end of the week and into the weekend as deterministic start
to diverge on the overall solution. While the GFS continues to show
a similar system that worked across the Ohio Valley Tuesday and
Wednesday with a stacked system working across the region, the EURO
is much weaker with just an upper-trough working in across the Ohio
Valley for Friday into the weekend. Depending on the solution, one
could feature a very wet solution (GFS) while the EURO is slightly
drier with lower overall rain chances for the weekend. Models do
agree on the development a mid-level trough over the central US and
an increase of low-level moisture out ahead of this across the Ohio
Valley. Could see shower and storm development ahead of this system
by Thursday night and continuing into the day Friday. PWAT values
increase ahead of the approaching system to over 1.50" by Friday
afternoon increasing the potential for locally heavy rainfall within
any convection that develops. While shear remains low, there should
be enough instability for a few embedded rumbles of thunder. The
main impact will be the heavy rain and potential for some very
localized minor flooding.

As mentioned above, confidence remains low for the weekend, while
the GFS shows a similar scenario similar to Wednesday with a slow
moving system with periods of rain and drizzle the EURO shows just
some scattered showers and thunderstorms. The models do agree on a
drier solution for Sunday as the main feature should be to our east.
Temperatures will also be impacted by which solution ends up
verifying, if we get the wetter/dreary GFS then highs Saturday will
be mainly in the 70s with highs in the 80s on Sunday while the drier
EURO would likely have temperatures closer to 80s and in the 80s for
the weekend.

Upper ridging looks to increase over the eastern US and Great Lakes
by early next week. This will help to warm temperatures up into the
mid 80s.

&&

.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 743 PM EDT Tue May 14 2024

Challenging TAF forecast ahead with multiple rounds of shower and
storm chances, lower ceilings, and perhaps some patchy fog that
could lower vis. Scattered showers and storms across the area this
evening will continue for a few hours after sunset, but should
eventually lose strength the closer we get to midnight. Flight
categories drop to MVFR or even IFR overnight with low stratus and
possibly some patchy fog. The low stratus seems to have the bigger
impact, so have hit that fairly hard in the TAFs. By tomorrow
morning, another wave of precip will be making its way into the
region. However, we should see some slight improvements to ceilings
after sunrise. Some scattered storms will once again be possible in
the afternoon hours, but have kept mention at VC due to the
difficulty of timing out scattered storms.

&&

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

&&

$$

UPDATE...CJP
SHORT TERM...MCK
LONG TERM...BTN
AVIATION...CJP