919
FXUS63 KJKL 180613 AAD
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
213 AM EDT Sat Oct 18 2025

.KEY MESSAGES...

- Expect one last very warm day on Saturday. A strong cold front
  will then bring strong to potentially damaging wind gusts as it
  crosses the area on Sunday morning.

- Following the front, expect blustery conditions with gusty
  showers and falling temperatures on Sunday afternoon.

- Another round of strong, gusty winds is expected on Tuesday
  afternoon as a second cold front moves through.

- Much colder air will settle in for next week, creating the
  potential for frost in sheltered valleys on Tuesday and
  Wednesday nights.

&&

.UPDATE...
Issued at 1223 AM EDT SAT OCT 18 2025

Observed temperatures in some of the coldest sheltered valleys in
our northeastern counties are at or below forecast lows, so
adjusted the overnight forecast minimums down to at least match
the current temperatures. Overall, made minor adjustments to Sky
grids in addition to the hourly T/Td updates for the next several
hours. Temperatures in these areas could still fall another few
degrees before dawn, but with no significant impacts as
temperatures are too warm for frost formation.

UPDATE Issued at 925 PM EDT FRI OCT 17 2025

With occasional breaks in the cloud cover anticipated based on
current and anticipated satellite trends, lowered Sky grids about
20 percent through the remainder of the overnight. Otherwise, the
forecast is on track with no significant changes.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 431 PM EDT FRI OCT 17 2025

Another tranquil October afternoon is unfolding across eastern
Kentucky, with temperatures mainly in the 70s and low dew points,
courtesy of a 1018 mb surface high centered over Lake Ontario at
20Z. Aloft, a 500 hPa ridge axis extends from the Florida
Panhandle northward across Kentucky and Michigan to James Bay.
Upstream, a negatively-tilted trough extends from Manitoba to the
Lower Colorado River Basin. This is mirrored at the surface by an
989 mb low near or over Lake Winnipeg, while an associated cold
front arcs southeastward across Minnesota and then southwestward
into New Mexico. A trailing northern stream upper-level trough
extends from the Northwest Territories to the Northern U.S.
Rockies.

The upper-level ridge and its associated surface high will
gradually propagate eastward tonight and Saturday, moving off the
Atlantic Seaboard during the second half of the weekend.
Meanwhile, the aforementioned trailing trough will dig deeply as
it dives southeast this weekend, effectively capturing the leading
upper-level trough and becoming a deep, negatively-tilting trough
over the Great Lakes and Ohio Valley by Sunday. The aforementioned
cold front, preceding the trough axis, will become the focal
point for rapid cyclogenesis, initially over the Osage Plains on
Saturday evening before racing northeast and deepening to an 985
mb low north of the Great Lakes by Sunday afternoon. Modest
southerly return flow tonight and Saturday will give way to an
intensifying warm conveyor belt jet pumping warmth and moisture
into eastern Kentucky on Saturday night with some GEFS mean 850 mb
winds of 40 to 50 kts, or 95th-plus percentile relative to
climatology. In many cool season events, low-level stability with
a warm frontal inversion, often enhanced by rainfall, would be
sufficient to preclude substantial momentum transfer from the warm
conveyor belt jet to the surface. However, as this event
approaches, the low-levels are likely to be dry and more mixed as
the surface pressure gradient will become sufficient (more than 4
mb across the area) for valleys that decouple early Saturday
evening to recouple overnight. Additionally, virga falling into
the dry sub- cloud layer ahead of the front could lead to
sufficient low-level lapse rate steepening for at least moderate
momentum transfer to the surface until the low-levels become
saturated and prohibitive to substantial momentum transfer until
the arrival of the front. The front appears to be sharply defined
with this system, likely forcing a narrow line of convection
(QLCS). While instability will be minimal and model sounding
equilibrium levels are low (generally warmer than -20C), strong
forcing and rapidly steepening lapse rates up to 850 mb or deeper
along the boundary could support strong momentum transfer right
along the frontal boundary, especially so in any segments of the
line that become more N-S to NW-SE oriented. This scenario could
lead to instances of damaging winds (noted in the SPC Day 2 and 3
Marginal CWO), despite insufficient instability for thunder in
most cases. Guidance generally favors stronger winds surfacing
ahead of the front around 8Z Sunday, with the actual frontal
passage occurring between 11Z and 17Z, west to east. While winds
may slacken for a few hours immediately behind the front, the
combination of diurnal surface heating, strong CAA, and a still-
robust 30 to 40 knot westerly 850 mb jet will set the stage for a
blustery afternoon with falling temperatures. GFS/NAM mixed-layer
momentum transfer guidance from BUFKIT continues to support
widespread gusts of 30 to 40 mph through much of the afternoon,
with the strongest gusts near and north of I-64. Shallow
convective showers in the post-frontal environment on Sunday
afternoon could lead to locally stronger wind gusts. The tumble in
850 mb temperatures, from 12-15C at sunrise to 2-5C by sunset,
will lead to falling surface temperatures through Sunday
afternoon.

In terms of sensible weather, fair conditions are expected for
this evening and tonight. Temperatures will fall into the low to
mid-50s for most, though some of the normally colder hollows could
dip into the 40s. On Saturday, mostly sunny skies will prevail,
with temperatures warming well above normal into the low to mid-80s,
aided by a southerly breeze. After a lull Saturday evening, south
to southwest winds will become increasingly gusty overnight, likely
reaching a peak with a narrow line of showers and possibly a
thunderstorm on Sunday morning. Overnight temperatures will hold
nearly steady in the 60s or even rise slightly. Strong winds,
gusting between 30 and 40 mph, and gusty showers are expected on
Sunday afternoon. Temperatures will start the day in the 60s to
near 70, but will fall into the 50s by sunset.

.LONG TERM...(Sunday through Friday)
Issued at 304 PM EDT FRI OCT 17 2025

The forecast period begins at the transition point between two
synoptic features. First, the weekends strong cold front will
depart, leaving lingering impacts over eastern Kentucky. To the
west, surface high pressure will begin nudging into the region.
Basically, the frontal boundary will slowly exit the area, and
through Sunday night, upper-level height rises and ridging will
usher surface high pressure into the region by Monday morning.
Behind the departing front, persistent upper-level northwesterly
flow will allow for CAA to establish itself overhead, resulting in
chilly overnight lows in the upper 30s to low 40s from Sunday night
into Monday.

Surface high pressure firmly entrenches itself on Monday. However,
throughout the day the upper-level ridge axis will shift eastward as
a new trough begins to approach the area from the west. This
eastward shift introduces southwesterly flow, advecting warmer air
into the region. High temperatures on Monday will climb into the mid
to upper 60s. Overnight lows Monday night into Tuesday are forecast
to be 5 to 10 degrees warmer as the WAA truly takes hold aloft.
Concurrently on Monday, the next weather system is forecast to track
off the lee of the Rockies into the Central Plains. A strong surface
low is forecast to develop and as the associated upper-level trough
continues to dig southeast, the surface feature is expected to lift
northeast into the Upper Midwest/Western Great Lakes. By Tuesday
morning, the vertically stacked upper-level feature is projected to
be over the Great Lakes. At the surface, its accompanying cold front
will be approaching the CWA. With an 80-to-90 knot jet core swinging
overhead and the presence of a surface boundary, there is a strong
potential for upper-level momentum to mix down to the surface.
Forecast soundings, coupled with indications from momentum transfer,
a strong Theta-E gradient, and high LREF probabilities (greater than
90 percent for gusts over 25 mph) indicate that strong wind gusts
of at least 25 mph are very likely with the frontal passage
Tuesday afternoon. The front itself appears to be moisture starved
and the locations most likely to see PoP are areas closer to the
Ohio River and north; meaning the forecast area is expected to be
dry but windy along the mostly dry cold front. As the area is
forecast to remain mostly dry Tuesday night, post-frontal CAA and
clear skies will allow for instances of frost development
overnight Tuesday.

Surface high pressure will build back into the region behind the
exiting cold front on Wednesday. Upper-level flow will remain out of
the northwest, maintaining CAA behind the front. This CAA is
reflected in daytime highs for Wednesday, which are expected to
struggle to climb much higher than the lower 60s. For Wednesday
night, the combination of clear skies and continued CAA creates the
potential for frost development across the sheltered valleys of
eastern Kentucky. While overnight lows are generally forecast to be
in the 30s to lower 40s, frost will be possible in favorable
locations due to anticipated radiational cooling under clear skies.

Thursday is forecast to see a subtle warm-up as a surface warm front
lifts northeast through the area early Thursday morning. Highs will
climb into the mid to upper 60s. However, an upper-level
perturbation is forecast to move through the mean flow, leading to
increased chances of precipitation beginning Thursday afternoon and
continuing through Friday afternoon. At this time, there is
noticeable disagreement among long-term deterministic models
regarding the precise timing and placement of the Thursday/Friday
synoptic features. Nonetheless, the overall trend indicates a
potential for scattered rain chances from Thursday through Friday.

Overall, the forecast period will be highlighted by multiple passing
disturbances bringing gusty to strong winds, some rain, and notable
temperature fluctuations. Temperatures will begin to trend toward
values expected for mid to late October, with the added potential
for isolated frost on Tuesday night and again Wednesday night.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 213 AM EDT SAT OCT 18 2025

Passing disturbances should continue to bring high and some mid
level clouds during the first 6 hours of the period. Valley fog
with reductions to MVFR and IFR is also anticipated through
around 13Z or 14Z and K1A6, KBYL, and KI35 may be affect, through
the TAF sites will not be affected. Outside of that, VFR
conditions will prevail. However, following light and variable
winds through around 13Z, but the approach of a strong cold front
will bring increasing south to southwest winds Saturday peaking
between 5 and 12 KT through 22Z before winds become more southerly
and 10KT or less sustained. Increasing winds just off the surface
will bring a threat for low level wind shear to end the period.

&&

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

&&

$$

UPDATE...JP
SHORT TERM...GEERTSON
LONG TERM...VORST
AVIATION...JP