500
FXUS63 KJKL 041017
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
517 AM EST Thu Dec 4 2025

.KEY MESSAGES...


- Cold and mainly dry weather persists through today.

- Wintry precipitation is possible overnight and into Friday.
  Precipitation will start as light snow, transitioning to rain
  Friday morning. However, can`t rule out some pockets of light
  freezing rain during this transition.

- The pattern is expected to remain active through the weekend and
  perhaps the middle of next week as well, though long term
  forecast confidence in details remains low.

&&

.SHORT TERM...(Today through Friday)
Issued at 513 AM EST THU DEC 4 2025

Generally zonal flow is on tap for today as a strong upper level low
moves across southeast Canada and a shortwave to our west begins to
elongate, leaving much of the Commonwealth in a W to E pattern. At
the surface, a weak cold front is expected to pass through during
the first half of the day, giving way to high pressure moving in
from the west - tracking just north of the CWA. Other than a drop in
temperatures, and a boost in some mid-level moisture (resulting in
cloud cover throughout the day), this cold front should have very
little impact and overall weather should be calm and cool throughout
the day.

That is until late this afternoon, as a strong jet streak moves over
the area and brings ovc high clouds into the region under WSW flow.
This is the first precursor to what is to come. While the center of
the surface high pressure continues to shift eastward just north of
the state tonight (Thursday night), a low pressure system and
inverted trough will be brewing across the Deep South. Models are
starting to come into better agreement that this inverted trough and
resulting boundary will reach as far north as southeast Kentucky.
Uncertainty remains, however, about how quickly moisture/precip will
move into the region, how much moisture/precip there will be, and
how far north it will reach. The evening/overnight CAMs were also in
better agreement, showing pops entering as early as 1 to 2Z, and
overspreading the S and SE CWA just before 6Z, before beginning to
exit eastward and dissipating between 12 and 15Z. The problem is
that other large-scale models (carrying over into the NBM) show a
more extensive expanse into the CWA, reaching much farther north and
taking longer to exit during the day. That being said, while we
match up well with our neighbors, and the highest pops match up well
with the CAMs, there is still some room for change, which could have
some impacts when talking about the next topic...precipitation type.

There has been a lot of uncertainty in the topic of precipitation
type as well, and while the forecasts are becoming more consistent,
it`s still a very tricky situation. Our location on the northern
fringe of this system puts us in the cold sector. However, where
precipitation and clouds are in place, temperatures will be
substantially warmer than that of the northern CWA, which may see a
bit of clearing and remain dry. The latest forecast shows overnight
low temperatures ranging from 18 degrees (well below freezing) in
the north, to around 30 degrees in the far south (just below the
freezing mark). So as the precipitation starts, the entire CWA
should be below freezing at the surface. Then as we head into the
morning hours on Friday, and the system begins to exit, surface
winds will quickly turn more southerly...and so we will begin to
warm. This may have impacts. While snow and frozen ground was the
story overnight, this warming could transition snowfall to a mix of
rain and snow, or just rain. Rain on frozen ground - freezing rain.
Thankfully, even as we start to warm, most of the precipitation
should remain snow until the temperatures are several degrees above
freezing, at which point it will just be rain. But there could be
pockets of freezing rain within the rain/snow. And just a 1 to 2
degree change in temperatures during this time period could be a
drastic difference on if the roads are fine, and if there`s more
widespread freezing rain.

Again, the models seem to be more consistent in the last couple of
runs, with generally light snow, some pockets of freezing rain, and
then a transition to all rain as the system moves out in the
morning/early afternoon and temperatures rise into the upper 30s
(north) and low/mid 40s (south). This results in generally under an
inch of snow south of I-64 during the morning hours, and only
sporadic pockets of very light ice accumulation in the same region.
This forecast also lines up well with our neighboring offices.

Given the uncertainties and the limited impacts of the current
forecast, no headlines are being issued at this time. However, we
are continuing to highlight it in the HWO and Key Messages since it
could have some impacts with the Friday morning commute. Since this
is still a very fluid/dynamic set-up, will let the day shift take
one last look at the next set of model guidance to see if anything
has shifted/altered which may lead to headlines.

According to the ECWMF, the surface low driving this system should
quickly exit off the Mid-Atlantic Coast by 0Z Saturday, with a weak
area of high pressure taking hold of the state (dry conditions), and
strong WSW flow remaining in place aloft. Despite this, the latest
forecast keeps lingering low pops across eastern KY into Friday
evening/night. Expect these pops are an artifact of the NBM (pulling
in previous data and some higher moisture models) and will be
removed in future runs...as is further discussed in the extended
portion of the forecast.

.LONG TERM...(Friday afternoon through Wednesday)
Issued at 315 PM EST WED DEC 3 2025

The forecast period begins with a surface low-pressure system
tracking northeastward from the Tennessee Valley, traversing the
CWA. This system straddles the short-term and extended forecast
periods. We have opted to segment the discussion based on the
phasing transition from wintry precipitation to all rain.
Consequently, this discussion begins Friday afternoon, where warm
frontal passage and diurnal warming will support precipitation
primarily as rain. The system is forecast to exit the region by late
Saturday morning. However, a brief period of wintry mix remains
plausible on the back side of the departing system as cold-air
advection returns to the region. Surface high pressure builds into
the area following the systems departure. Nevertheless, upper-level
southwesterly flow will maintain relatively mild temperatures for
Saturday.

An upper-level trough stalled over the Hudson Bay area and
an impinging shortwave trough moving off the Rocky Mountains will
interact beginning Sunday, driving the weather pattern from Sunday
through late Monday. The first of these perturbations is associated
with a dry cold front extending from the Hudson Bay trough. A key
feature is the zone of baroclinicity that the secondary low-pressure
system, originating from the Rockies, can track along. This
secondary system is more moisture-rich and should yield higher
probabilities for rain and snow beginning early Sunday morning and
persisting through late Monday morning. Precipitation type (p-type)
will be temperature-driven, with daytime temperatures generally
supporting rain, while overnight temperatures will favor a wintry
mix or snow. Model confidence is low regarding thermal profiles and
the precise track of the low-pressure center. Therefore, little
confidence is placed in deterministic snowfall totals. Behind this
system, surface high pressure will rebuild across the area for
Tuesday, but model trends indicate another system approaching by the
end of the forecast period.

The period will be characterized by multiple synoptic disturbances
traversing the area, bringing an array of precipitation types
followed by interludes of high pressure. Temperatures are generally
forecast to remain below average for this time of year.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday)
ISSUED AT 1134 PM EST WED DEC 3 2025

Mid-level clouds are developing from west to east across the area,
with IFR cigs rapidly approaching KSYM from the west, poised to
arrive at the terminal not too long after TAF issuance. These
low-MVFR/IFR cigs will move west to east and expand south with
time as a cold front passes late tonight, and then largely persist
across the terminals until around 00z Fri before beginning to
scatter out as the next system quickly approaches from the west.
Winds will remain light and variable through the period.

&&

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

&&

$$

SHORT TERM...JMW
LONG TERM...VORST
AVIATION...CMC