799
FXUS63 KJKL 292000
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
400 PM EDT Mon Apr 29 2024

.KEY MESSAGES...

- Showers and thunderstorms arrive from west to east tonight and
  linger into much of Tuesday.

- Dry and trending warmer midweek, with near record highs on
  Thursday.

- Unsettled weather returns for Friday and lingers through the
  weekend.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 357 PM EDT MON APR 29 2024

We`ve been following this system moving in tonight for quite a while
now. And with each forecast, it looks a little less and a little
less impressive.

A closed low is currently in place across Minnesota and will
continue to shift northward into tonight, weakening only slightly.
This will create a shortwave which should pass through the Ohio
Valley tonight into Tuesday. At the surface, a low pressure system
will be present moving across the Upper Great Lakes overnight. This
system is already occluded and will continue to wrap around itself
into the overnight. A cold front connected to this low will be
orientated from NE to SW, slowly sweeping the Commonwealth
tonight and during the day Thursday. Perhaps it`s because we are
quite a distance away from the parent low, perhaps it`s because
the cold front never quite makes it all the way through the state
before lifting back northward, or perhaps it`s because there isn`t
a large airmass shift with this system...either way, the warm
moist environment in place and passing boundary would support the
potential for thunderstorms, but they just don`t look very strong.
There is very little organization (llvl wind sheer is basically
nill), the sounding is very saturated, and there is very little
CAPE. That being said, a more likely concern with these storms as
they move in is the heavy rain potential. Can`t rule out that some
locations could receive heavy downpours from storms that may lead
to some isolated flooding concerns.

The system should finally exit to our east by Tuesday evening. Light
and somewhat variable surface winds are expected behind this system
overnight, along with dry air advection, helping to clear out the
skies. With this set up, expect cooler temperatures Tuesday night
compared to tonight, and it is possible that some of the deeper
valleys could decouple and drop temperatures fairly quickly. Tried
to include a ridge/valley split in the forecast, though if it
does pan out, may not have gone extreme enough on the differences.


.LONG TERM...(Tuesday night through Sunday)
Issued at 355 AM EDT MON APR 29 2024

The 29/00z model suite analysis beginning Tuesday evening shows an
upper level shortwave trough across the Mid-Ohio Valley down
through the Southern Appalachians. A more substantial upper low/
trough is found over much the Canadian prairie provinces as well
as over northern portions of the CONUS from Washington to the
Dakotas. At the surface, the decaying remnants of a cold frontal
boundary will extend southwestward into Kentucky from a weak low
over the Mid-Atlantic states while weak high pressure is centered
over the Tennessee Valley. Further west, weak low pressure is
found over the northern Plains with an associated cold front
extending southward into Texas.

The first decaying cold front, will decay near/over the Commonwealth
on Tuesday night, with any associated shower activity tapering off.
Heights will begin to rise as the upper level shortwave trough
exits to the east. Thus, skies should clear for the most part,
setting the stage for efficient radiative cooling; which,
combined with light winds and low-level moisture from any rainfall
earlier in the day, will set the stage for fairly extensive
radiation fog formation through the overnight. By Wednesday, the
upper level low over the northwest CONUS will begin to amplify
while a counterbalancing ridge begins to rise across the Ohio
Valley and Southern/Central Appalachians, reaching peak intensity
late Thursday. This will funnel very warm air mass northward
across the eastern Kentucky Coalfields, especially on Thursday
when 850mb temperatures may exceed 17C (40-60% chance south of
I-64, less than 40% north). Given deep mixing, 850 mb temperatures
of this magnitude would easily support temperatures warming to
near record levels in the mid and upper 80s. The amplified pattern
begins to break down on Thursday night and Friday, with the ridge
being shunted southeast while the western upper low tracks toward
the Hudson Bay. As this occurs,a surface low reflection will
develop and track from the Plains into northern Ontario and push
a cold front, and renewed rain chances, into eastern Kentucky on
Friday into Saturday. Little in the way of forcing will leave the
surface front hanging up near/south of our forecast area this
weekend. Model agreement then diverges significantly with respect
to the overall pattern, though there are suggestions that a
disturbance could ride along the boundary and bring rain chances
on Sunday as well.

In sensible terms, the first day of May will likely start off
foggy for many of the valley locales before yielding to ample
sunshine area-wide. Wednesday will turn quite warm with high
temperatures forecast to reach the upper 70s to lower 80s. Even
hotter temperatures, in the middle to upper 80s, are on tap for
Thursday under bright May sunshine. A few isolated 90 degree
readings cannot be ruled out, most likely in the deep valleys of
the Big Sandy river basin. Shower and thunder chances return on
Friday as the next cold front arrives. However, temperatures are
still forecast to jump into the 80s before the deeper moisture
moves in. Periodic shower and thunderstorm chances are also in
the forecast heading through the weekend as that front stalls and
potentially becomes the focus for additional rainfall, at times,
over the weekend, though forecaster confidence in the details is
low. Daily maximum temperatures are forecast to drop back into the
mid 70s to lower 80s for the both weekend days. Nighttime lows
should mainly range between 52 and 67 through the period, coolest
Tuesday night and warmest on Thursday night.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 157 PM EDT MON APR 29 2024

VFR conditions are currently in place across the region, with
increasing SW flow. Unfortunately the pattern is beginning to
change, as a system is nearing from the west. Gusts should cease
by this evening, but predominate SW flow should linger. Showers
and scattered thunderstorms should begin to move in from the west
to east overnight, with scattered to widespread precip expected to
continue through the TAF period. Ceilings will slowly diminish
throughout the period as well, eventually reaching MVFR status by
late tomorrow morning and early afternoon.

&&

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

$$

SHORT TERM...JMW
LONG TERM...GEERTSON
AVIATION...JMW