750
FXUS63 KJKL 150502
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
102 AM EDT Thu May 15 2025

.KEY MESSAGES...

- Shower/storm chances linger for much of this week and into the
  weekend early next week, especially during the afternoon and
  evening hours.

- There is the potential for isolated organized thunderstorms
  Thursday into Thursday night, with a a greater risk for
  organized severe weather Friday into Friday night.

- Temperatures are expected to moderate about 10 degrees above
  normal for Thursday and Friday - then be back closer to normal
  from Saturday through Tuesday.

&&

.UPDATE...
Issued at 101 AM EDT THU MAY 15 2025

So far only a few pin dot showers have occurred in the northwest
portion of the area. Looking more likely that we`ll remain capped
overnight, and less likely that much will happen. Have left a
20-30% POP in before 12Z, but even that may be overdoing it. Also
lowered tonight`s min temperatures slightly in eastern valleys
based on evening trends.

UPDATE Issued at 916 PM EDT WED MAY 14 2025

Based on lack of development so far and latest model runs, have
backed off on the POP for tonight. There still may be some
development in the warm air advection regime, but the probability
looks to be lower than what was previously forecast, and the new
values are below the likely category (<55%).

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 242 PM EDT WED MAY 14 2025

Upper trough axis departs to the north and east through tonight, but
a shortwave within upstream west-northwesterly flow will move across
the area this evening into the overnight and bring an increased
chance for showers and thunderstorms. The SPC has continued to
expand the Marginal Risk for severe storms this evening through
much of the overnight to include all the but the far northeastern
areas. Isolated damaging winds and/or large hail will be possible
with the strongest of these storms.

Mid-level height rises occur late tonight through the day Thursday
behind tonight`s shortwave passage, and should keep any shower and
thunderstorm threat relatively isolated if not completely
suppressed, but another shortwave will arrive Thursday night and be
accompanied by mid-level height falls. The SPC has issued a Day 2
Marginal Risk for severe storms, mainly for the chance of evening
and overnight storms, though it is possible the primary threat holds
off until or after daybreak Friday.

With rising heights and suppressed cloud cover and convection
Thursday, high temperatures will warm significantly into the mid- to
upper-80s, with overnight lows Thursday night remaining quite mild
in the upper-60s to lower-70s within a warm advection regime and
plentiful clouds.

.LONG TERM...(Friday through Wednesday)
Issued at 450 PM EDT WED MAY 14 2025

The models, and their individual ensemble suites, have come into
better agreement aloft through the first part of the long term
portion of the forecast and are well aligned during the weekend.
However, some greater discrepancies start to crop up for the
first part of the new work week. They all now depict quite
similarly the compact, closed h5 trough pushing east out of the
Upper Midwest and through the northern Great Lakes. This is well
north of ridging through the central Gulf Coast States and up into
the Deep South initially, but suppressed south with time. The
large northern trough will dominate the Great Lakes region and
into the Ohio Valley through the weekend north of that flattening
southern ridge. This sets up a fast stream of deep mid-level flow
through Kentucky tilting from the southwest to more zonal into
Saturday. This flow will sustain a warm and moist environment in
the lower levels while several distinct short waves trough the
region before the northern trough passes by to the northeast
tilting the flow more northwesterly. By Sunday, 5h heights will be
climbing locally as the Gulf ridge rebounds into the region -
quickest in the GFS ensembles than the ECMWF. This ridge builds
north through the breadth of the Mississippi Valley ahead of
another large upstream trough diving through the Rockies. Into
midweek, ridging will move overhead of Kentucky as the western
troughing lifts quickly to the Central Plains and into the Upper
Midwest. This pattern then shifts east with 5h height falls coming
in from the west as that trough opens up and spreads its energy
into the region from the northwest - though stronger and more
contained in the operational GFS than the ECMWF. The rather small
model spread for the bulk of the long term supported using the NBM
as the starting point with minimal adjustments needed - mainly to
include some radiational cooling based terrain distinction in
temperatures at night over the weekend.

Sensible weather features a stormy start to the long term portion
of the forecast as a stacked, strong - but gradually weakening -
sfc low will be moving into the Great Lakes region into Saturday.
Locally, this will lure a warm front north into Kentucky from the
south on Friday where it will likely stall just north of the state
before pushing back south as the main northern system`s cold
front on Saturday. During that process, though, each mid level
impulse will likely be enough to generate storm clusters to the
northwest of the area that then wash over the JKL CWA downstream
with a potential for heavy rain and severe weather - probably
lessening during the life cycle. The NAM12 would imply that one
of these develop Friday afternoon in northwest Kentucky then fades
out before affecting much of the eastern part of the state - not
ready to bite on this and expect the activity to be able to
sustain into our area through the day given the relatively primed
thermodynamics and healthy low level shear. Later that night
another round should develop to the north and likely spreads in
during the early morning hours. This seems reasonable and could be
the main threat for severe weather with this system. CIPS
analogues are also highlighting this time range for the best
chances for severe weather from organized convection that upscales
into an MCS and comes through the area with damaging wind gusts
as the primary threat.

These storms are expected to help push the cold front deeper into
southeast Kentucky and possibly all the way through into
Tennessee early Saturday. However, there is a strong potential
for the boundary to linger with additional shower and storm
chances through Saturday evening. Drier air then looks to move
into the area that night with some clearing, radiational cooling,
and valley fog anticipated. Sunday should be dry, but there is a
small potential that the cold front will start to work back north
and set up for more shower chances. The western Cumberland Valley
will have the best shot at renewed convection on Sunday. Likewise,
Monday (after another night of radiation cooling) will see that
boundary to the southwest perhaps getting active enough for more
showers in the Cumberland Valley. Have also included some
radiation cooling/terrain based differences for low temperatures
that night in the northeast ahead of that returning front. For
Tuesday and Wednesday that boundary will likely be in place over
portions of eastern Kentucky allowing for more convection with
storms possible Tuesday night and through the day Wednesday -
aided by more upper support and height falls arriving from the
northwest.

The changes to the NBM starting point consisted primarily of
adding terrain distinction to the temperatures for Saturday and
Sunday nights. As for PoPs - did not deviate from the NBM
solution given the similar model clustering and net results for
this part of the area though refinement to timing and extent will
be needed in forthcoming forecasts.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 101 AM EDT THU MAY 15 2025

Primarily VFR conditions are forecast through the period, with
just a couple of exceptions. Valley fog will occur overnight and
early Thursday, but should not affect TAF sites. Also, scattered
showers/thunderstorms may affect some places, but confidence is
too low for inclusion in TAFs. Fog or precipitation would bring
localized sub-VFR conditions.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...HAL
SHORT TERM...CMC
LONG TERM...GREIF
AVIATION...HAL