256
FXUS63 KJKL 181945
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
345 PM 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 tonight and for 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 this
  evening and Friday, the moisture will make a comeback heading
  into next week.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 345 PM EDT THU JUL 18 2024

19Z sfc analysis shows cooler and drier high pressure starting to
build in from the northwest in the wake of a slowly departing
cold front. With this pattern change the clouds are clearing from
northwest to southeast as that drier, and more stable, air
arrives. This is most evident in the dewpoints that currently
range from the mid 50s northwest to around 70 in the far
southeast. Meanwhile, mostly based on returning sunshine in the
wake of the front, temperatures vary from the low 80s north to the
mid and upper 70s in the southeast. At the same time, winds have
turned more northerly through this part of the state and are
running at less than 10 mph.

The models, and their individual ensemble suites, are in
excellent agreement aloft through the the short term portion of
the forecast. They all depict a seemingly persistent troughing
through the Great Lakes and Ohio Valley downstream of a nearly
perpetual dome of high heights over the Four Corners region. This
keeps eastern Kentucky in zonal, to slightly southwesterly, mid
level flow through Saturday morning. Mainly weak impulses will
track through the area aloft in this flow pattern even as local 5h
heights tick up a bit to end the work week. Given the small model
spread have gone with the NBM as the starting point for the
forecast grids with little adjustment needed aside from some
incorporation of the latest CAMs guidance for PoPs for thr latter
portion of the period.

Sensible weather features a welcomed cooler and less humid night
on account of high pressure`s semi-push into the region. This ends
by mid-day Friday, though, when the cold front to our south
starts to work back north as a warm front - guiding our next
chances of convection into this part of the state into Saturday
morning. Did allow for some terrain distinction tonight, but
mainly for just the northwest portion of the area that will have
the best shot at being mostly clear the longest. Did also include
a touch of river valley fog to account for more limited cloud
cover and radiational conditions for a good portion of the CWA
tonight and perhaps the northwest portion on Friday night.
Otherwise, shower and thunderstorm chances creep back in Friday
afternoon and will work deeper into the state from the south
through that night.

The main changes to the NBM starting point consisted of adding in
some PoPs details from the CAMs for Friday and Friday night. Did
also tweak northwest parts of area for some terrain distinctions
tonight and again for a lesser amount on Friday night.

.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 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 205 PM EDT THU JUL 18 2024

Residual shower activity has basically exited the bulk of the
area. This departure is taking the MVFR/IFR CIGs out along with
the PoPs. As a result, just about all terminals have turned VFR
with the rest to follow shortly. Winds will be mostly out of the
north to northeast yet generally light at only 3 to 7 kts into the
evening. Outside of that, winds will be light and variable. Any
fog tonight will likely be confined to the valleys not impacting
the TAF sites.

&&

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

$$

SHORT TERM...GREIF
LONG TERM...AR
AVIATION...CMC/GREIF