914
FXUS63 KJKL 222001
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
401 PM EDT Wed May 22 2024

.KEY MESSAGES...

- There is a potential for showers and thunderstorms at times from
  today through Tuesday.

- A few storms this afternoon/evening and again Sunday could be
  strong to severe, with damaging winds and large hail being the
  primary threats.

- An increase in clouds and the possibility of rain will lead to
  somewhat cooler temperatures from Thursday into the first of
  next week.

&&

.UPDATE...
Issued at 220 PM EDT WED MAY 22 2024

Convection is still rather sparse as a broken line advances slowly
southeast into the area. The most concentrated area is arriving in
our southwestern counties, and the POP in that area has been
increase to 60 percent for this afternoon.

UPDATE Issued at 1058 AM EDT WED MAY 22 2024

A broken line of showers/thunderstorms extends from around KBWG
northeast to just north of KFGX late this morning. The general
scenario in the latest model runs is for this area to continue
shifting slowly southeast and persist into tonight as it makes its
way through the JKL forecast area. Using chance POPs at this
point, but the evolution will be watched, and there is a potential
for higher POPs to be needed. Latest model runs are also now
looking like additional convection arriving from the west during
the night will be a little slower, and have gone with a later
arrival.

UPDATE Issued at 700 AM EDT WED MAY 22 2024

Did a quick update to the forecast grids using trends from the
latest obs. Temperatures have been running warmer than forecast
overnight, so the latest obs were used to establish new trends and
to also update this mornings lows, as they were a bit too warm as
well.

&&

.SHORT TERM...(Today through Thursday)
Issued at 401 AM EDT WED MAY 22 2024

A somewhat challenging forecast in the short term this time
around. A cold front will approach the area from the northwest
through out the day today, and will be the trigger for showers and
storms around eastern Kentucky today through Thursday. The front
is expected to eventually stall out somewhere along the Ohio
River. The challenge will be determining how far south the front
will go before it stalls. The further southeast the front goes,
the higher our rain chances will be today. The position of the
front varies a bit from model to model, so no solid consensus has
been reached as of yet regarding the boundary. Due to this
uncertainty, decided to keep precip chances a bit lower than the
latest NBM data was suggesting, going more toward the lower MOS
guidance for PoPs. The latest runs of the higher resolution
models(HRRR, NAMNEST, CAMS, etc) differed as well with the start
times and initiation of showers and storms today. Having said
that, liked the latest HRRR solution for initiation and evolution
of convection across our area, especially late tonight and
Thursday, when the cold front is forecast to push through. In a
nutshell, the highest probability for showers and storms occur
during from very late tonight and through the day on Thursday
during frontal passage.

What we do know is with plenty of low level moisture and
instability will be in place to support convection, and that
showers and storms will form and move across eastern Kentucky
today, especially this afternoon and evening, during peak heating.
We also know that a few storms could be strong to severe and
could produce damaging wind gusts or even an isolated instance of
large hail. After a few days of extremely warm temperatures,
things will finally cool off a bit today and Thursday due to
persistent, increasing cloud cover and repeated rounds of showers
and storms. Winds will be on the increase today as well and will
be generally out of the southwest at 5 to 10 mph, with gusts of 15
to 20 mph possible at times.

.LONG TERM...(Friday through Wednesday)
Issued at 401 PM EDT WED MAY 22 2024

An active pattern is shaping up across the Ohio Valley through the
extended period of the forecast. The period begin Friday, with a
mid-level wave pushing toward the lower Ohio Valley and Tennessee
Valley. The various ensembles and deterministic have been varying
a little on placement and timing of this feature. This will give
way to around a 60-80 percent chance of showers and thunderstorms
mainly Friday afternoon and evening. The highs will be closer to
normal in the upper 70s to lower 80s.

Saturday, a ill defined frontal boundary will be nearby and this
could spark off a few showers and thunderstorms (around 40-60
percent chance), but coverage looks a little less, with better
mid- and upper level forcing west of the area. This as we see
slight height rises ahead of another mid-level wave noted in the
Plains. The weakly sheared environment would suggest anything that
does form would be unorganized.

Sunday into Sunday night the previously mentioned trough will push
east and surface low will eject out of the Plains into the Midwest.
This will send a round of showers and thunderstorms toward the Ohio
Valley Sunday afternoon and another wave possible Sunday night. The
parameter space right now looks a little better for more organized
convection, with MUCAPE values around 1500-2500 J/kg amid 40-50
knots of effective shear. The question will be how do the
multiple rounds of convection trend and how does that affect what
happens downstream. This as, some of the medium range CAM
solutions suggest overnight convection pushes into eastern
Kentucky by Sunday afternoon. Either way it was enough for SPC to
include a portion of eastern Kentucky in slight risk for severe
weather given the favorable pattern. The primary hazards would be
damaging wind gusts and large hail.

Sunday night into Monday the previously mention low pressure is
forecast to push into the Great Lakes as it becomes vertically
stacked in the mid- and upper levels. This will help pull a cold
front across the area by Monday afternoon. Given the uncertainty
in overnight convective evolution the risk for severe weather is
uncertain. Even so, some ensemble and deterministic guidance
suggest the potential for marginally severe storms would be
possible in far eastern and southeastern parts of Kentucky, with a
cold front pushing across the area. This as EPS/GEFS/GEPS
ensemble mean of greater than 1000 J/kg of CAPE matched with
greater than 30 knots of bulk shear is around 30 percent.

More uncertainty comes Tuesday and Wednesday, as a mid- and upper
level closed low pushes across the Ohio Valley and into the
Northeast. This will help send another cold front across the area
during this time period with models showing several different
solutions of timing and evolution. Given this stuck with the general
chance range for PoPs (at around 25-40 percent peaking in the
afternoon. The pattern overall looks much cooler to round out the
period, with highs forecast to be in the low to mid 70s both
Tuesday and Wednesday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 220 PM EDT WED MAY 22 2024

An area of showers/thunderstorms is currently making its way into
eastern KY from the west. Coverage is incomplete, and the TAFs are
presently being handled with VCTS due to uncertainty of where they
will hit. However, IFR or worse conditions can be expected in the
heavier precip. Outside of the precip, mainly VFR conditions are
expected until early Thursday morning. A more widespread area of
showers/thunderstorms is forecast to arrive from the west on
Thursday morning with IFR and MVFR conditions.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...HAL
SHORT TERM...AR
LONG TERM...DJ
AVIATION...HAL