652
FXUS63 KJKL 181123
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
723 AM EDT Thu Jul 18 2024

.KEY MESSAGES...

- Showers and thunderstorms will impact the region at times
  through the middle of next week. The lowest probability of rain
  occurs Thursday night and much of Friday. Probabilities then
  increase as we move into the new week.

- A welcomed relief from hot temperatures is underway through the
  middle of next week. However, after a drop in humidity Thursday
  and Friday, the moisture will make a comeback as we move into
  next week.

&&

.UPDATE...
Issued at 624 AM EDT THU JUL 18 2024

Widespread showers with a few thunderstorms have worked over the
atmosphere and zapped any lingering instability across the area
ahead of the cold front. That, plus significant cloud cover across
eastern Kentucky, may make it difficult for the atmosphere to
destabilize through the remainder of this morning and early
afternoon. For that reason, began to conservatively lower the
Probability of Thunder grids, and thus thunderstorm chances,
through this afternoon. Still kept some >15 percent probabilities
in the southeastern two tiers of counties as there is some chance
that steepening lapse rates this afternoon with the upper trough
passage could trigger a few storms.

Other changes this morning were to smooth out PoP discrepancies
with neighboring offices, and to update and initialize the
forecast with the latest hourly observations.

&&

.SHORT TERM...(Today through Friday)
Issued at 330 AM EDT THU JUL 18 2024

Weak instability and plentiful moisture are contributing to
scattered to widespread showers and isolated thunderstorms early
this morning over southern parts of the forecast area. This is in
association with a cold front that is dragging its heels in moving
across the forecast area, with the front analyzed as still being
over the Bluegrass region as of 03z last evening. Eventually this
front will move southeast through the remainder of the forecast area
through this afternoon, with a renewed round of showers and
thunderstorms likely developing roughly over and south of a KY-
80/Hal Rogers Parkway line later this morning into early afternoon
before moving southeast into southwest VA and northeast TN by
evening and clearing the area of precipitation.

Cooler and drier air filters into the area today from the north as
the area comes increasingly under the influence of surface high
pressure to the north. With just some thin high clouds and the
cooler and drier air mass, lows tonight will fall into the mid-50s
to lower-60s.

For Friday, the cooler and drier air mass remains across the CWA,
but a mid-level disturbance will move north-northeast and clip
southeastern KY late in the afternoon. Models suggest modest
moisture return and meager instability, but enough to warrant slight
chance to chance PoPs in the grids across the southern half of
the forecast area.

.LONG TERM...(Friday night through Wednesday)
Issued at 335 AM EDT THU JUL 18 2024

The extended period is beginning to look very active based on the
latest long term models. The latest runs of the GFS, ECMWF, GFS
Ensembles, and WPC analysis have a frontal boundary setting up
initially across the souther tier of states from the southern Plains
eastward across the Gulf of Mexico states and lower Tennessee
Valley. It appears that with time, this boundary will begin moving
slowly northward as waves of low pressure form and move west to east
along it. We will experience periods of showers and storms across
the area through out the extended, as the front meanders about in
the Tennessee Valley over the weekend. We will see our highest
precipitation chances during the afternoon and evening hours, during
peak heating and as waves of low pressure move by just to our south
along the front. We should see periods of lesser rain coverage
Saturday and Sunday, as the front makes a couple of southward
migrations. By Monday, however, it looks like the front will drift
further northward than it will over the weekend. This will lead to
longer bouts of rainfall across the area, with or northern areas
seeing more rainfall. The front will hang up over our area by
Tuesday and Wednesday, and will lead to the highest, persistent
precipitation chances we`ll see in the extended over the bulk of the
forecast area.

The good news is, with persistent widespread cloud cover and
numerous bouts of rain expected, temperatures should average below
normal through out the period. In fact, most days should see max
temperatures in the upper 70s and lower 80s. Humidity will be on the
higher side still, but the lower temperatures should make it
bearable.

The primary forecast concern in the extended will be the potential
for locally heavy rainfall and minor flooding issues that may arise
as a result. In a nutshell, it looks like we will see a very active
weather across eastern Kentucky from Saturday through the middle of
next week, as a sluggish frontal boundary sets up nearby and
eventually right over the area. Afternoon and evening periods will
be the most active, as peak heating and instability are in place.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 722 AM EDT THU JUL 18 2024

Residual shower activity will slowly wane and/or move east out of
the area through the remainder of this morning. MVFR/IFR
conditions will thus slowly improve to VFR by late morning or
early afternoon. Additional showers and thunderstorms may develop
by early to mid-afternoon, but this activity is expected to
remain south of the TAF sites. Winds, outside of any storms, will
mostly be out of the north to northwest yet generally light at
only 3 to 7 kts in the afternoon. Outside of that, winds will be
light and variable.

&&

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

$$

UPDATE...CMC
SHORT TERM...CMC
LONG TERM...AR
AVIATION...CMC