763
FXUS63 KJKL 260015 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
815 PM EDT Sat May 25 2024

.KEY MESSAGES...

- There is a potential for severe thunderstorms on Sunday and
  Sunday night, with damaging winds, large hail, and tornadoes all
  possible.

- Showers and thunderstorms are expected from time to time through
  the middle of next week, especially during the afternoon and
  early evening hours.

- A bit of a cool down is expected after Monday, behind the
  passage of the cold front.

&&

.UPDATE...
Issued at 745 PM EDT SAT MAY 25 2024

23Z sfc analysis shows weak high pressure over eastern Kentucky
southeast of a slowly approaching cold front from the northwest.
This has kept most of the area rain-free today along with light
winds and partly cloudy skies. A couple cells of convection are
noted to the northwest of the JKL CWA but growth has been meager
so far. Currently, temperatures are generally in the 70s while
dewpoints remain elevated in the mid 60s to even some lower 70s.
Did a quick update to the grids through the night, mainly to lower
PoPs on the front end per radar and satellite trends. Did also
add in the latest obs and tendencies for the T/Td/Sky grids.
Finally, touched up the fog threat later tonight, mainly for the
valleys. These minor adjustments have been sent to the NDFD and
web servers.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 514 PM EDT SAT MAY 25 2024

A few showers have begun developing in central KY again after
heating occurred this afternoon. They are moving east and should
develop a bit more into early evening, making their way into the
JKL forecast area. However, there is not much discernible upper
level support and air aloft is dry, so as weak ridging aloft
moves over us from the west it should help to shut off any
remaining convection late tonight. That will leave quiet
conditions lasting into Sunday morning.

Things get active again during the day Sunday, with a significant
threat of severe wx. Thunderstorm currently erupting over the
plains will raise eastward through Sunday as strong surface low
pressure crosses the Midwest. With mesoscale influences playing a
role, models are still showing variation in the evolution of the
convection, but a blended model solution would suggest convection
developing here in the afternoon. Forecast parameters are
supportive of severe storms in terms of 2-3K J/KG ML CAPE and
favorable speed and directional shear. This yields Bulk Richardson
numbers on Sunday afternoon and evening favorable for supercells.
The most favorable late day shear and instability is shown in our
western counties, and SPC has placed an enhanced risk area
extending eastward into that area (with slight risk further to the
east). Models are suggesting this initial round of convection in
the afternoon and evening, followed by more convection ahead of
the system`s cold front later on Sunday night into Monday morning.
Flow is more unidirectional with the later convection and
instability not as strong, but flow aloft is still brisk, and a
primarily wind threat is still a possibility with the late night
convection.

.LONG TERM...(Monday through Saturday)
Issued at 552 PM EDT SAT MAY 25 2024

We will start off the period on Monday on the heals of an impactful
weather system Sunday and Sunday night. By Monday morning, the cold
front associated with this strong surface and upper level system
will quickly traverse KY, exiting the east side of the state by
~18Z. A line of showers and thunderstorms will likely be present
along the frontal boundary, one of several lines that will impact
the CWA through Monday morning.

Precip should taper off behind the front by Monday evening, giving
way to drier wrap around air from the surface and upper level low.
This influx of drier air will help to clear out clouds, and will
also advect in a cooler airmass from our north, despite surface
winds remaining from the W to SW. Overnight lows will settle in the
50s, around 5 to 10 degrees less than the previous night.

The strong and broad-reaching upper level trough axis will persist
across the state through midweek before finally starting to shift
eastward Thursday, where it will stall again through the remainder
of the period.

During this time, several other upper level lows will rotate through
the trough, bringing unsettled weather to the Ohio Valley and Great
Lakes at times. The first of these will be on Tuesday. All the
models have a different solution on how this will play out, with the
ECMWF and NAM keeping eastern KY mostly dry. However, the GFS brings
the shortwave farther south and precip moves across much of the
state late in the day. The NBM has trended down on pops related to
this system, only bringing in some slight chances in the far east and
northeast of the CWA Tuesday afternoon with peak heating. Didn`t see
any reason to increase it at this point, and models are still
evolving on Day 4. A similar situation arises on Wednesday afternoon
as a shortwave moves through the trough as the axis begins to shift
eastward. Models show the potential for precip to graze eastern KY
during this time, mainly during afternoon peak heating. The NBM
followed suit by another day of isolated pops for a few hours in the
afternoon in the NE CWA.

During the time that the trough is impacting the Ohio Valley, strong
N to NW flow will be in place aloft. This will keep temperatures at
or just below seasonal normals for this time of year during the day.
During the overnight, good radiational cooling with light winds will
help to quickly drop temperatures. It will also lead to some decent
ridge/valley differences in temperatures as well. Expect
temperatures to generally be in the upper 40s and low 50s, some 5 to
10 degrees below normal.

A gradual warm up will be on tap again as we close out the week and
head into the weekend. The trough will continue to shift east,
introducing a strong but short-lived ridge across the region, and
surface high pressure. Rising heights and the imposing high pressure
system should keep conditions dry both Thursday and Friday. From
this point forward there is quite a bit of disagreement. A storm
system generally over the Plains seems to stay in place through the
end of the forecast period, keeping high pressure across JKL through
the end of the period. The NBM, however, shows a quicker progression
of this system eastward, introducing pops into the CWA by Friday
night and continuing into Saturday. The fact that they are only
isolated, however, is hopefully a trend towards the drier
solutions. &&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 241 PM EDT SAT MAY 25 2024

Largely VFR conditions are forecast during the period, with a
couple of localized exception. A few showers/thunderstorms with
sub-VFR conditions are possible late this afternoon and evening.
Valley fog is also expected to develop late tonight and last into
Sunday morning before dissipating. MOS guidance is hitting the fog
fairly hard at TAF sites. However, if precip does not occur, it
would seem to be more questionable. A TEMPO group for IFR
conditions has been used in the TAFS for several hours around
sunrise.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 815 PM EDT SAT MAY 25 2024

Predominantly VFR conditions are expected during the period, with
a couple of localized exceptions. A stray shower/thunderstorm
with sub-VFR conditions is possible through the evening. Later,
valley fog is also expected to develop and last into Sunday
morning before dissipating. MOS guidance is hitting the fog fairly
hard at the TAF sites. However, if precip does not occur, it is
more questionable. Therefore a TEMPO group for MVFR/IFR
conditions was used in most of the TAFS for several hours around
sunrise. There will also be a potential for poorer conditions with
more storm development and interactions around midday Sunday and
through the afternoon. Winds during the aviation period will be
light and variable, away from any storms.

&&

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

$$

UPDATE...GREIF
SHORT TERM...HAL
LONG TERM...JMW
AVIATION...HAL/GREIF