-- Discussion containing changed information from previous version are highlighted. --
795
FXUS63 KJKL 121657
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1257 PM EDT Sun May 12 2024

.KEY MESSAGES...

- Precipitation free weather reigns through Monday morning, before
  an approaching system from the Plains brings more unsettled
  conditions.

- Near normal temperatures today through Wednesday will be
  followed up by warmer conditions through the rest of the week.

&&

.UPDATE...
Issued at 850 AM EDT SUN MAY 12 2024

Another quick tweak to remove the morning valley fog wording from
the radio and zone forecasts.

UPDATE Issued at 735 AM EDT SUN MAY 12 2024

Just a touch up to the forecast with this update mainly to add in
the latest obs and trends for the T/Td/Sky grids. These minor
tweaks have been sent to the NDFD and web servers.

&&

.SHORT TERM...(Today through Monday)
Issued at 430 AM EDT SUN MAY 12 2024

08Z sfc analysis shows high pressure in control of the weather
over eastern Kentucky this night. This has led to mostly clear
skies and light winds resulting in good radiational cooling and a
decent ridge to valley temperature split. Specifically, readings
range from the lower 40s in a few of the most sheltered spots in
the east to the lower 50s on the hilltops. Meanwhile, dewpoints
have fallen into the low and mid 40s most places. On satellite a
batch of 7k or so feet high clouds are passing through the
northeast parts of the area and the limited river valley fog is
evident - thickest southeast. This fog will clear out shortly
after dawn.

The models, and their individual ensemble suites, remain in
excellent agreement aloft through the short term portion of the
forecast. They all depict the nearby shortwave trough departing
off to the northeast today allowing ridging to ease in from the
Plains. The 5h height rises with this system peak late tonight
before the mid level flow turns southwesterly ahead of another
closed low trough pushing across the Plains. Some mid-level energy
leads this feature and slips into this part of the state by Monday
evening. The model spread remains fairly small with these key
forecast elements so the NBM was used as the starting point for
the short term grids along with the incorporation of the CAMs`
details for PoPs and timing with the next chances of precipitation
later Monday.

Sensible weather features a nice warm up after a chilly start
today, thanks to ample sunshine and an early clearing of the fog.
High pressure does start to shift off to the east tonight
allowing for one more night of mostly clear skies and another
ridge to valley temperature split throughout it. Again some
limited river valley fog will be around early Monday morning. More
clouds arrive on Monday in the return flow ahead of the next
weather system. These will spread northeast through the day to
start the work week with shower chances following a short time
later. There will also be a small shot at some thunder by evening
with those showers on Monday. Despite the arriving clouds and
convection, temperatures will still be able to meet and exceed
normal values on Monday afternoon.

The main adjustments to the NBM starting point again consisted of
adding in some terrain details to the hourly temperatures and
lows both this morning and again tonight. As for PoPs - the NBM
values were adjusted to include some of the CAMs ideas for the
shower and small thunder chances on Monday afternoon.

.LONG TERM...(Monday night through Saturday)
Issued at 344 AM EDT SUN MAY 12 2024

The 12/0Z suite of model solutions appear to be in slightly
better agreement through the extended as compared to this time
yesterday. Plains low pressure and associated trough are poised to
enter the lower Ohio and Tennessee valley areas at the start of
the period. This system manages to get through our area during the
first 48 hours of the extended, weakening and opening up into a
trough as it tracks slowly eastward. Shortwave ridging will
transit the Ohio Valley late Wednesday through Thursday, providing
a brief lull in the unsettled weather pattern that will dominate
the extended. Phasing of northern and southern stream energy
result in a trough that moves through the Ohio Valley during the
last 24-36 hours of the forecast window (Fri- Sat). At the
surface, two low pressure systems at the start and end of the
extended will bookend surface high pressure that drifts eastward
across our area Thursday.

Sensible weather features generally unsettled weather through the
extended with a brief pause in the weather on Thursday. Thus the
extended begins with a round of rainy weather which persist
through Tuesday night and Wednesday, before slowly tapering off
from the northwest late Wednesday as a trailing cold front passes
through eastern Kentucky. Weak instability and shear will keep any
threat for severe storms in check with this first system. While
increasing PWATs of 1.2-1.4 inches aren`t spectacular, there does
appear to be a period elevated 850 mb moisture convergence under
notable upper level divergence by Tuesday afternoon and evening
just ahead of the surface low. This may lead to a period of more
steady moderate rainfall for portions of eastern Kentucky. WPC has
issued a Marginal risk ERO for this time frame as a result.

Further out in time, high pressure does exert its influence
briefly from Wednesday night into Thursday, providing a lull in
the threat of rain. Meanwhile, a northern Rockies trough and
Pacific low will translate eastward and phase into a deeper trough
that will eventually pivot across the eastern CONUS late in the
week. This second system will bring another round of showers and
thunderstorms to our area Friday through Saturday.

Temperatures will average above normal through the period, but
more as a result of overnight lows in the 60s running 5 to 10
degrees above normal. Exception will be Wednesday night into
Thursday morning as high pressure provides one night of lighter
winds, and at least partially clearing which will promote decent
radiative cooling, allowing temps to fall into the mid 50s across
most of the area. Tried to go with a muted diurnal range for the
remainder of the period because of added cloud cover and higher
PoPs. Afternoon highs will run about normal overall, mid 70s on
average.

&&

.AVIATION...
-- Changed Discussion --
(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1257 PM EDT SUN MAY 12 2024

Tranquil flying conditions for this forecast period. Winds
generally will be light and variable. Winds will start picking up
from the south early Monday afternoon. Otherwise, Monday morning
could see some patchy valley fog, but the terminals should stay
VFR.
-- End Changed Discussion --

&&

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

$$

UPDATE...SHARP/GREIF
SHORT TERM...GREIF
LONG TERM...GEERTSON/RAY
AVIATION...SHARP