889
FXUS63 KJKL 200511
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
111 AM EDT Mon May 20 2024

.KEY MESSAGES...

- Dry weather is expected area wide through Wednesday morning.

- There is a potential for showers and thunderstorms at times from
  Wednesday afternoon through Sunday.

- Very warm temperatures will persist through Wednesday. An
  increase in clouds and the possibility of rain will bring
  somewhat lower temperature after that, especially Thursday and
  Friday.

&&

.UPDATE...
Issued at 1202 AM EDT MON MAY 20 2024

Hourly grids were freshened up based on recent observations and
trends. Fog has begun to develop in parts of the Middle and South
Fork of the KY River basin where some light showers occurred
during the late afternoon to early evening. Additional fog
formation is expected over the next couple of hours with the
maximum areal extent of fog, mainly in valleys, anticipated near
sunrise.

UPDATE Issued at 910 PM EDT SUN MAY 19 2024

Hourly grids were updated based on recent observations and trends.
This led to no substantial changes. The earlier high based cumulus
and/or altocumulus have largely dissipate setting the stage for a
good net radiational cooling night. Valley fog should form
overnight and in some cases dewpoint depressions are already 5 or
less. This valley fog may possibly form as early the midnight to
2 AM timeframe and the timing of this has been adjusted earlier in
the grids at this point.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 325 PM EDT SUN MAY 19 2024

Southwest/northeast oriented ridging at all levels will slowly pass
east over the region during the period, resulting in dry weather
with mainly clear skies. Strong, nearly full sun (within about a
month of summer solstice) will result in very warm afternoon
temperatures on Monday, well into the 80s. Our atmosphere aloft
will continue to be very dry, creating good radiating conditions.
With light low levels winds, valleys will readily decouple from
the flow each evening, leading to typical ridge/valley min
temperature differences, as well as valley fog. The temperatures
differences will be greatest on Monday night, as weak warm air
advection keeps ridges warmer than tonight.

.LONG TERM...(Tuesday through Sunday)
Issued at 415 PM EDT SUN MAY 19 2024

We will start the extended period on the last dry day for the
remainder of the 7-day stretch. High pressure and upper level
ridging will be exiting to the east, but we will remain under their
influence throughout the day Tuesday. Meanwhile, return SW flow will
aid in increased WAA across the region, with highs topping out in
the mid and upper 80s once more.

At the same time, a strong low pressure system will be brewing
across the Central Plains during the afternoon on Tuesday,
coinciding with a deepening shortwave and development of a closed
low in the upper levels. This system will be quickly shifting
northeast, strengthening substantially by the time it reaches the
Upper Great Lakes by 12Z Wednesday. By this point it will already
start becoming occluded, with a warm front spreading east across the
Great Lakes region, and a cold front draped southward across the
Mississippi Valley. The end of this cold front will be in TX, where
another low pressure system exists. During the day Wednesday the
strong system will continue to push northeast, dragging the cold
front eastward. However, the southern edge of the front will become
stationary in TX, causing the front to become more elongated, laid
out from SW to NE across much of the eastern U.S., and directly
across the Commonwealth. Pops from this front will begin moving into
the JKL CWA by Wednesday afternoon, becoming more widespread during
the day Thursday as the front slows it`s progression and becomes
stalled east to west across Kentucky.

With a lot of the forcing from the upper level system continuing to
move away from the state, and the front weakening, it is likely that
it will lose some energy heading into the nighttime hours Thursday
night, so kept with NBM backing down to scattered pops. However, the
ECMWF and GFS both show a surface low and shortwave moving across
the state during the day Friday. This, along with daytime heating
and increased lift/instability along the frontal boundary still in
place, could increase pops back to likely once more during the day
Friday.

A similar situation will happen Friday night into Saturday, with
pops decreasing during the overnight, and ramping back up during the
afternoon hours Saturday as the remnants of the boundary remain
present. Models are also showing a second system setting up to our
west Friday into Saturday. Unfortunately, there is no agreement on
the timing. If the GFS is true, it will be impacting eastern KY by
Saturday afternoon. Meanwhile, the ECWMF is quite a bit slower, with
the system just starting to impact the western end of the state late
Saturday afternoon/evening. Will be interested to see how these both
shake out. Either way, expect chances for rain and storms on
Saturday, just like the days leading up to it.

As for temperatures, Tuesday and Wednesday will be the warmest days,
ahead of the front and in the SW flow sector. Once the front moves
through and becomes stationary, clouds will also be a commonplace,
with temperatures maxing out in the upper 70s to around 80. Models
show a warm up back to the low to mid 80s by Saturday, but a lot of
this is dependent on the above-mentioned system brewing to our west
during that time, so expect these numbers to fluctuate over the
coming days as models begin to come into better agreement.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 111 AM EDT MON MAY 20 2024

Continuity was maintained with the 06z TAFs with no changes from
the 00z TAFs.

Other than fog, especially in the valleys during the 05Z to 13Z
timeframe, VFR conditions are anticipated. Guidance suggests KLOZ
and KSME should have a few hours of MVFR reductions, with valley
fog lifting into KSJS for a few hours near 12Z with reductions
possibly into the IFR range. Winds will average less than 10KT
through the period.

&&

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

$$

UPDATE...JP
SHORT TERM...HAL
LONG TERM...JMW
AVIATION...CMC