296
FXUS63 KJKL 050957
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
557 AM EDT Wed Jun 5 2024

.KEY MESSAGES...

- Showers and thunderstorms will affect the area today and
  tonight.

- Relatively cooler and drier weather will arrive behind a cold
  front passing through eastern Kentucky on Thursday.

&&

.SHORT TERM...(Today through Thursday)
Issued at 557 AM EDT WED JUN 5 2024

A strong upper low (by June standards) will move east southeast
from Saskatchewan to the upper Great Lakes during the period. An
elongated trough/wave rotating around the south side of the low
was roughly over the Mississippi Valley early this morning, and
will approach our area today and depart to our east tonight. It
will support a weak surface cold front accompanying it. The
approach of the front and upper trough will support showers and
thunderstorms in the warm and moist air present over our area
today into tonight. Precipitation will diminish as the front and
upper trough depart tonight and early Thursday. Models disagree on
how much drying takes place initially behind the front. The
greatest amount of drying will be behind a secondary front which
will be entering the forecast area from the northwest Thursday
evening. Before that happens, models suggest some additional
shower develop on Thursday afternoon as the second front
approaches. Forecast soundings show shallow instability capped in
the mid levels-- convective currents not tall enough for thunder,
but deep enough for precip. As mentioned, there is still some
variance in models regarding the setup ahead of the second front,
and the GFS and HRRR are the most aggressive at generating light
precipitation. Have used a 20% late day POP at this time.

.LONG TERM...(Thursday night through Tuesday)
Issued at 350 AM EDT WED JUN 5 2024

The 05/00z model suite is generally in good synoptic agreement at
the start of the period before spread increases this weekend/early
next week. Initially, an ~548 dam low is in place over the Upper
Great Lakes, embedded within a swale extending northwestward in
the Yukon. This relative troughing is sandwiched between a
prominent ridge over the western CONUS and another orphaned ridge
axis aligned from Labrador/Quebec northwestward into the eastern
Beaufort Sea. At the surface, a regional analysis shows an ~991 mb
low south of James Bay while its cold front extends southward in
to the Central Appalachians and then extends southwestward along
the southern side of the of Ohio River, including across Kentucky,
and beyond across the Ozarks. High pressure is found just north
of the boundary across the the Central and Northern Plains.

The cold front sags across southeast Kentucky late Thursday
evening as the parent upper low drifts toward the Lower Great
Lakes. The upper level forcing with this system remains well
north of of the Commonwealth, leaving just the weak low-level
convergence along the front to spark convection under a strong
~600 mb cap. The potential for lingering scattered convection is
depicted by a majority of the 00z CAMs suite. Once that front
clears the area, a drier and cooler air mass will move in on
northwesterly breezes late Thursday Night and Friday as surface
high pressure sinks southeastward into the Tennessee Valley/Mid-
South Saturday night. Meanwhile, a vort max over the Canadian
Prairies, will pivot, either in part or whole, around the upper
low over the Lower Great Lakes, bringing another surface cold
front to the Eastern Kentucky Coalfields. The system`s evolution
will have a significant bearing on the rain chances late this
weekend and early next week, depending upon whether this vort max
remains more of a progressive open wave or forms a slow-moving
closed low.

Sensible weather will feature a diminishing threat for showers on
Thursday evening. Once the precipitation ends, fair weather can
be expected into Saturday morning with slightly cooler temperatures,
ranging mainly in the mid to upper 70s for highs and in the lower
to mid 50s for lows. A few of the coldest hollows could see upper
40s on Friday night. While the specifics are still uncertain, the
daily threat for showers and even a few thunderstorms is very
likely to return on Saturday and persist into early next week as
the next cold front and upper level system approach. Forecast
high temperatures generally range from the mid to upper 70s
through the remainder of the forecast period while nighttime lows
bottom out in the mid to upper 50s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 557 AM EDT WED JUN 5 2024

Scattered showers were affecting the region at the start of the
period, and conditions varied widely from VFR to VLIFR. Most of
the showers will taper overnight, but conditions will continue to
vary. Conditions are forecast to eventually settle to mostly MVFR
around 10-12Z, and then improve to mostly VFR by around 16Z.
However, additional showers and thunderstorms should develop,
especially in the afternoon. They will bring localized sub-VFR
conditions. The activity will last well into the night. Although
most places should see precip bring lowered ceilings/visibilities
at some point from the afternoon into the night, the
predictability of timing at any given location is too low to
specify it in the TAFs, and VCTS has been used.

&&

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

$$

SHORT TERM...HAL
LONG TERM...GEERTSON
AVIATION...HAL