147
FXUS63 KJKL 221307 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
807 AM EST Mon Dec 22 2025

.KEY MESSAGES...

- Temperatures will moderate to much warmer than normal values by
  Christmas day, and these continue into this weekend.

- Periodic rain chances will occur through much of the holiday
  week.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 512 AM EST MON DEC 22 2025

Early this morning, an upper level trough extended from eastern
Canada across sections of the Maritimes and Northeast to east of
the eastern seaboard while upper level ridging was centered over
the Gulf and extended across southern portions of the Conus and
also north into sections of the Central Conus. The axis of this
upper level ridge was currently west of eastern KY and there has
been a trend of rising heights overnight. An associated lowering
subsidence inversion has brought dewpoints to -10F or lower above
2500 feet overnight and to -20F to -30F or lower for the top of
Black Mountain. A nocturnal inversion was in place below that and
KY Mesonet and home weather station indicate that deeper mainly
valley and hollow locations have dropped off into the upper teens
to lower 20s range while many coalfield ridgetop locations were
around 30 and the high ridges above 2500 feet within the
subsidence inversion were even warm in the mid 30s per KY Mesonet
and KY RWIS stations. A 1036 mb ridge of sfc high pressure
meanwhile was centered across the Central Appalachians and
extended across much of the eastern Conus and aided in the
development of the nocturnal inversion when combined with only a
few passing high clouds.

Today, the axis of the upper level ridge will shift east with the
trend of rising 500 mb heights expected into the afternoon before
height tendencies are generally neutral late north of the upper
ridge that remains centered in the Gulf vicinity. The sfc high
will move east to the eastern seaboard and a passing shortwave/
disturbance will combine with return flow for an increase in
moisture aloft starting this afternoon. The low levels will remain
very dry due to the ridging in place with a more gradual increase
in sfc dewpoints/moisture compared to increases aloft between 700
mb and 900 mb as well as temperatures. Mainly passing high clouds
should dominate this morning with increasing low and mid level
cloud cover this afternoon.

Tonight and Tuesday, the upper ridging centered in the Gulf is
expected to build into sections of the Southern Plains with height
rises in sections of the Rockies and Plains/Central Conus. At the
same time, a shortwave moving near the US/Canadian border is
expected to reach Ontario and the western Great Lakes late tonight
and then progress to near the Ontario and Quebec border to
eastern Great Lakes. Sfc low pressure preceding this trough will
reach near the Ontario and Quebec border with the trailing cold
front sweeping across the Great Lakes and into parts of the
Northeast/ mid Atlantic while the western extent sags into the OH
valley and sections of the Central Conus. Low level to mid level
moisture is expected to be in place tonight, though guidance
suggests it gets shallower nearer to dawn on Tuesday and remains
mainly confined to near 850 mb an below for much of Tuesday before
increasing again late in the period.

During the evening into the overnight, some at least patchy light
rain is anticipated as the shortwave/disturbance passes and model
time heights have an increase in omega coinciding with the
increased low to mid level moisture. Behind that shortwave, a bit
of a lull in pops is expected from mid to late Tuesday morning
into the afternoon. However, as the front nears later in the day
to early in the evening Tuesday, another uptick in omega should
coincide the modest increase in low level moisture and may result
in an increase in coverage of patchy light rain by early Tuesday
evening. Chances for light rain appear more substantial after dark
on Tuesday, early in the long term period.

Temperatures moderate to above normal level today with a north to
south gradient in temperatures with highs forecast to be about 5
degrees above normal north and nearer to 10 above normal in the
south. Milder lows tonight are expected with the cloud cover
though there could be a window in the evening where some deeper
valleys cool off before the clouds thicken. Highs on Tuesday are
forecast to reach 10 or more degrees above normal areawide on
Tuesday with southwest flow ahead of the front.

.LONG TERM...(Tuesday night through Sunday)
Issued at 510 AM EST MON DEC 22 2025

The model agreement remains solid regarding unseasonably strong
ridging that will be in place across the south central U.S.
through Christmas Eve while deeper troughing encroaches upon the
West Coast. The models differ more so after Christmas Day, as the
ECWMF remains faster with the trough coming onshore compared to
the GFS. These differences will have larger implications
downstream through this weekend, with the ECWMF depicting a deeper
trough/closed low that moves east along the U.S./Canadian border.
This would sustain the unseasonably warm temperatures longer
across the Ohio and Tennessee valleys, as short wave ridging would
be renewed east of the Mississippi River out ahead of the trough.
The GFS is less amplified and further north with the trajectory
of this system. This would allow for more zonal flow in the East,
with at least slightly cooler temperatures in place, before the
passage of a more decisive cold front by the end of the week. As
such, confidence in the forecast goes down markedly after
Christmas, and especially by Sunday. This is also confirmed by the
more abrupt increase in model spread regarding the temperatures
seen in the blended guidance by the end of the week.

A progressive cold front will start out across eastern Kentucky
Tuesday night, sustaining some rain chances over the area, before
the boundary sags into the Tennessee Valley by early Wednesday
morning. Lows will range from the mid 40s north of the Mountain
Parkway to the mid 50s near the Tennessee border. This boundary
will then shift back northeast over the Coalfields as a warm front
on Wednesday, bringing at least slight chances of rain. Highs
will rebound to the upper 50s north, to the mid 60s south. An
uptick in 850 mb moisture transport associated with a nocturnal
low level jet will bring likely rain chances back into the area
after dark on Christmas Eve, with the highest chances favored
closer to the Ohio River, where there will be somewhat better
upper level support. Lows will be in the low to mid 50s.

Christmas Day, temperatures will climb into the mid to upper 60s
under mostly cloudy skies and diminishing rain chances through the
day, as 850 mb moisture transport weakens. Yet another 850 mb jet
uptick occurs Thursday night, bringing the next increase in rain
chances across eastern Kentucky. Again, model agreement has
diminished here, as the ECMWF now delays the progression of the cold
front, while the GFS pushes this boundary through the area Friday
into Saturday, with temperatures quite a bit cooler on highs by that
time comparatively. Either way, rain chances continue in the
forecast through the period, but are somewhat less compared to the
guidance from last night. On Sunday, a stronger cold front will move
through the Commonwealth, with a better chance of rain once again
and possibly the last day of above normal temperatures for this
stretch of warmth, depending on model trends.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 739 AM EST MON DEC 22 2025

VFR conditions are noted across the Commonwealth at TAF issuance
and will continue for a vast majority of the period and VFR should
continue through at least the 00Z to 03Z timeframe. High pressure
will keep clouds limited to the mid and high levels at times
until 21Z or later when low level moisture and clouds increase
followed by light rain chances as a warm front and disturbance
approach. A few locations in the west and northwest could reach
MVFR ceilings by 06Z including KSYM with MVFR spreading to the
east and southeast to end the period. Some light rain will reach
the ground within it and there could be times where ceilings are
in the lower end of the MVFR range. Winds will be light and
variable initially, becoming southeast to south at less than 10KT
between 15Z and 18Z. Finally, a low- level jet will lead to
a level wind shear threat between about 02Z and 13Z.

&&

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

&&

$$

SHORT TERM...JP
LONG TERM...JKL
AVIATION...JP