-- Discussion containing changed information from previous version are highlighted. --
407
FXUS63 KJKL 230530
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
130 AM EDT Thu May 23 2024

.KEY MESSAGES...

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

- A few storms 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...
-- Changed Discussion --
Issued at 1130 PM EDT WED MAY 22 2024

The MCS is raining itself out leaving behind thinning clouds and
damp ground late this evening. These ingredients will create a
period of fog for many places before additional clouds and a
renewed threat of storms move in from the west towards dawn. Have
updated the forecast mainly to lower PoPs for the next several
hours and beef up the fog. Did also include the latest obs and
trends for the T/Td/Sky grids. These adjustments have been sent to
the NDFD and web servers along with forthcoming updates of the
zones, SAFs, and HWO.

UPDATE Issued at 745 PM EDT WED MAY 22 2024

23Z sfc analysis shows a stalling cold front to the northwest of
eastern Kentucky keeping the area in a juicy air mass primed for
periodic bouts of thunderstorms. This evening, the strongest ones,
locally, are currently rolling east along the KY/TN border east
of I-75. Additionally storms are located closer to the front to
the northwest of the area and may affect this part of the state
later this evening, but this is not well supported by the latest
CAMs. Otherwise, the flooding and flash flooding threat in the
south will slowly diminish into the rest of the evening as the MCS
continues to weaken. Currently, temperatures vary from the rain-
cooled mid 60s in the southwest parts of the CWA to the mid and
upper 70s out ahead of any convection. At the same time, dewpoints
are rather moist in the low to mid 60s amid generally light
southwest winds of 10 mph or less outside of any storms. Have
updated the forecast to capture the cooler air with the rains as
well as the latest CAMs ideas for the PoPs. This included adding
in the obs and trends for the T/Td/Sky grids. These updates have
been sent to the NDFD and web servers along with a freshening of
the zones and SAFS.
-- End Changed Discussion --

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 426 PM EDT WED MAY 22 2024

A cold front was situated from near Paducah to Detroit this
afternoon, weakening and slowing down as it headed southeast. The
front should stall as it tries to move into KY. Humid air is
present ahead of the front and has been fueling some showers and
thunderstorms. However, clouds have hindered destabilization in
many places. Even where sunshine did send temperatures into the
80s, activity has been limited due to a lack of significant upper
level features. With modest shear in place and ML CAPE of
2500-3000 J/KG where heating occurred, if storms can develop or
move in, severe weather can`t be ruled out and will need to be
watched closely. The greatest concentration of showers and storms
is currently headed into our southwestern counties and the
highest POP has been placed there as we head into the evening.
Models suggest this will last into the evening, followed by a
general decrease in activity across the region at least until
dawn approaches. A shortwave trough currently supporting
convection in TX and OK will move rapidly east northeast and
should support a round of showers/thunderstorms moving into our
area early Thursday morning. This will hinder destabilization on
Thursday and limit a severe wx threat. The precipitation is
forecast to decrease from west to east in the afternoon, leaving
only minimal potential for anything else through Thursday night.

.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...
-- Changed Discussion --
(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 130 AM EDT THU MAY 23 2024

Showers and storms that were plaguing the area at the 0Z TAF
issuance have since dissipated/moved out of the area. We should
see a lull in activity overnight. The showers and storms will
again fire back up Thursday morning, and will become widespread at
times during the day, especially between roughly 15 and 22Z. as
a meandering frontal boundary moves around the area. The rain
should begin to taper off by around 0Z, as the front shifts
northward as a warm front. The challenge overnight will the fog
forecast. JKL has been plagued off and on the past few hours by
dense fog and extremely low CIGs, with IFR and even LIFR occurring
at times. These conditions will likely fluctuate for the next
several hours, with JKL seeing periods of both IFR or worse, and
VFR. Once the showers and storms fire back up later this morning,
the fog should be washed out for the most part, but any TAF sites
that experience a thunderstorm could see MVFR or even IFR
conditions for brief periods. Other than that, VFR conditions
should prevail for the most part. Winds outside of any
thunderstorm or intense shower should be out of the southwest and
relatively light.
-- End Changed Discussion --

&&

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

$$

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