Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

476
FXUS63 KJKL 210857
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
457 AM EDT Sat Mar 21 2026

.KEY MESSAGES...

- Temperatures steadily warm through the weekend, climbing into
  the mid and upper 70s today then into the 80s on Sunday.

- A few thunderstorms - potentially strong - will develop in the
  far south later this afternoon before fading out this evening.

- A well-defined and rather strong cold front on Sunday night will
  bring more widespread shower and thunderstorm chances to the4
  area along with a noticeable cooldown. Strong storms cannot be
  ruled out.

- Ahead of that front, record or near record highs are anticipated
  for Sunday along with gusty winds to at least the 20 to 30 mph
  range in the afternoon and evening.

&&

.SHORT TERM...(Today through Sunday)
Issued at 410 AM EDT SAT MAR 21 2026

07Z sfc analysis shows a mostly dry front settling south through
eastern Kentucky connecting low pressure east of the state with a
developing low to the west. This boundary remains the focus for
potential shower activity into dawn across far southeastern parts
of the JKL CWA, but most likely we will stay dry with just some
sprinkles around. Winds are rather light from the north behind
the diffuse front while light from the south ahead of it - all
under mid and high level cloud cover that is keeping any fog at
bay for the valleys despite lower dewpoint depressions. As such,
we are noting a small to moderate ridge to valley temperature
difference this night with readings varying from the mid 50s in
the sheltered low spots to the low and mid 60s amid the thermal
belts. Meanwhile, dewpoints are generally in the upper 40s to
lower 50s.

The models, and their individual ensemble suites, are still in
pretty good agreement aloft through the short term portion of the
forecast. They all depict the weakening of the western mega-ridge
underway while broad troughing continues east of the Mississippi.
This maintains a healthy amount of northwest flow at mid levels
through Kentucky with an initial impulse passing by to the
northeast early this morning. Meanwhile, an upstream batch of
energy - stronger in the models this night than 24 hours ago - is
on deck to dive southeast into the region later today. Though it
does weaken before arriving after 00Z it will probably be plenty
enough to initiate or sustain convection as its influence arrives
around peak heating. This wave passes during the evening with the
pattern flattening from the north as a dominant trough presses
south into the northern Ohio Valley. From this, more energy will
be on the CWA doorstep or nearing the Ohio River by 00Z Monday.
With still quite similar model solutions through the short term
portion of the forecast, the NBM was used as the starting point of
the grids. The main adjustments made to this initialization were
to incorporate more in the way PoP and thunder details from the
latest CAMs to help fine tune the convective threat late this
afternoon and evening in the south and again late in the day
Sunday in the north.

Sensible weather features a taste of summer today and especially
on Sunday ahead of a southward moving cold front. Frontal
interaction and just enough support aloft may allow for a few
thunderstorms to develop along and south of the Cumberland River
mainly for late in the afternoon. With a decent pocket of
instability building in the far south a couple of the storms could
become strong before sunset. The boundary partially responsible
for the convection potential then moves back north tonight - but
slowly enough that we could see some and inversion and radiational
cooling set up for a time allowing the deeper northern valleys to
decouple and cool off to a greater extent than the surrounding
areas - likely mixing out by dawn Sunday as winds start to kick
up. Breezy southwest winds will help send temperatures well into
the 80s for much of the area by late Sunday afternoon under
partial sunshine. This will provide energy that could help fuel
thunderstorms developing later that evening - spurred by a front
dropping in from the north and helping to weaken the thermodynamic
cap. Owing to the forecast soundings and wind profiles that set
up off the sfc later Sunday - severe weather is a threat - though
also dependent on the meso-scale evolution of the expected storm
cluster that looks to develop in Ohio. More details on this
evolution and threats to eastern Kentucky follow in the longer
term portion of these AM discussions.

The changes to the NBM starting point primarily consisted of
beefing up the PoPs to chance in the far south late this
afternoon into the evening, as well as allowing a slight chance
for storms to impinge from the north by late Sunday afternoon.

.LONG TERM...(Sunday night through Friday)
Issued at 457 AM EDT Sat Mar 21 2026

When the long term forecast period opens on Sunday evening, all eyes
will be on the evolution of ongoing convection north of the I-64
corridor. While currently available deterministic model soundings
continue to depict strong capping and efficient diurnal mixing over
much of eastern Kentucky during the daytime hours, this event now
resides at the tail end of the temporal resolution of higher-
resolution CAM data. 00z HREF mean ensemble soundings in the
vicinity of Fleming County, KY show the cap eroding in the Bluegrass
region right before sunset, alongside 1000-2000 J/kg of CAPE and 30-
40 knots of effective bulk shear. If such an environment comes to
fruition at the start of the forecast period, it would be more than
enough to support an isolated, discrete supercell thunderstorm. SPC
has accordingly upgraded far northern portions of the JKL CWA to a
Slight (Level 2/5) Risk for Severe Weather on Sunday evening. Dry
air in the midlevels and 700-500mb lapse rates averaging around 7.25
C/km in this time frame would support the development of hail in any
sufficiently strong updrafts, and while they cannot be entirely
ruled out, the tornado threat will be on the lower end given the
limited amount of low-level moisture. These first two hazards types
are contingent upon discrete convection developing or moving into
area north of I-64 at the very beginning of the forecast period. At
the time of writing, it remains uncertain as to whether or not that
discrete convection will fire within our forecast area, but we will
definitely keep a close eye on radar tomorrow evening.

Further to the south, the primary concern is for damaging wind gusts
as convection evolves into linear segments or a better-organized
QLCS. However, the convective parameter spacing is not as robust
down there. The loss of diurnal heating will quickly drop the
magnitude of the available CAPE after dark, and a nocturnal radiation
inversion develops over time within the currently available forecast
model soundings through 06z. However, thanks to persistent
prefrontal southwesterly winds, dewpoints will remain in the upper
50s to near 60. The resultant reduced dewpoint depressions (relative
to ones forecast while the sun is up) and the remaining 500-1000
J/kg of skinny CAPE will combine with increasing amounts of shear
parallel to the approaching frontal boundary to support outlining a
Marginal (Level 1/5) Risk for damaging winds down to the KY-80/Hal
Rogers Parkway corridor on Sunday night. One thing that we will need
to monitor for is a scenario in which outflow races south out of the
initial convection near the Ohio River. This could both undercut the
surface-based instability of any developing QLCS and force
additional discrete activity ahead of the main line. The 06z HRRR
resolves something to this, and other CAM soundings suggest that the
aforementioned skinny CAPE could be elevated above a more stable
boundary layer. This would likely reduce the intensity ceiling of
this event, but multiple model cycles will need to portray this
before the event is entirely written off. Interests should review
their nocturnal severe weather safety plans ahead of time, just in
case. At the bare minimum, this main line of activity will come in
the form of gusty rain showers sweeping south-southeast across the
commonwealth. The highest rain chances with this system (60-80%)
come to the east of I-75 and to the north of the Cumberland River
basin on Sunday night. The system`s progressive nature and weaning
intensity will likely keep storm total QPF amounts below 0.5 inches,
although locally heavier rainfall is possible within any stronger
convection.

Precipitation is expected to quickly taper off on Monday
morning as the parent frontal boundary pushes through the forecast
area. Forecast guidance continues to collectively drop 1000-500mb
layer relative humidity readings to below 35% by Monday afternoon,
which suggests that cloud cover should also clear out quickly behind
the front. Breezy postfrontal winds out of the north will advect a
drier and cooler continental airmass into the region. These winds
are associated with a Canadian high that is forecast to settle into
the Midwest in the wake of this early-period system. Aloft, the
forecast area will be positioned within a regime of quasi-zonal
zonal flow. These synoptics favor efficient diurnal mixing and the
persistence of dry air in the low- and mid-level portions of the
atmospheric column. Expect early next week to feel noticeably cooler
and drier outside than it did this weekend. Highs on Monday are
forecast to be in the 50s/near 60; this is 20-30 degrees colder than
Sunday`s near record warmth. Temperatures on Monday night will drop
back down below climatological averages, with thermometer readings
in the 30s area-wide. Ridge-valley splits cannot be ruled out.
Tuesday looks a little bit warmer at the high begins to propagate
east, with highs returning to the low to mid 60s. Both days look
very dry, as moisture return looks to hold off until mid-week. In
accordance with the BUFKIT momentum transfer soundings and mixed-
layer GFS/NAM data that is climatologically known to perform well in
patterns like this, dewpoints were lowered below baseline NBM
guidance on Monday and Tuesday afternoon. This corresponds with
MinRH readings in the 30s on Monday and potentially below the 25%
critical threshold on Tuesday. Thankfully, winds do not appear to be
particularly vigorous in this surface high pressure regime, and fire
weather interests are encouraged to monitor for forecast updates
pertinent to burning in this time frame. Expect partly to mostly
cloudy skies on both days, with more high-level cloud cover present
on Tuesday.

Low-level winds begin to veer to the south on Tuesday night into
Wednesday, bringing about the aforementioned moisture return. The
resultant increase in cloud cover will insulate overnight lows and
introduce the next round of rain chances to the forecast area. There
is a 25-35% chance of warm air advection rain showers across the
entire forecast area on Wednesday, with greater rain chances coming
later in the week as the next synoptic system approaches the region.
Model spread related to that system remains high, so confidence in
specific sensible weather details is low at this moment in time. It
is plausible that the current NBM grids are underestimating the
magnitude of prefrontal southwesterly return flow on Thursday, and
temperatures could accordingly warm back up into the mid/upper 70s
by then. This could present the next chances for thunderstorms in
the area, but the aforementioned forecast uncertainty masks timing
and intensity details. Temperatures will likely cool back down to
highs in the 50s and lows in the 30s behind that system`s cold
front, and it appears that we have settled into a traditional
springtime weather pattern for the latter stages of March here in
Eastern Kentucky.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 145 AM EDT SAT MAR 21 2026

VFR conditions will generally prevail through the TAF forecast. A
weak cold front approaches from the north, resulting in increased
cloud coverage, but these look to be holding in the mid to high
range. The front and any associated convective chances could
briefly impact the KSJS terminal as the front drops from north to
south through 08Z but the odds are too low to even include a
PROB30. As for winds, those settled to light and variable with
the loss of diurnal heating, but a period of LLWS from the west
at up to 40 kts is possible just ahead of the front. During the
day, winds will be generally around 5 kts from the west southwest
in the south and light/variable to the north.

&&

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

&&

$$

SHORT TERM...GREIF
LONG TERM...MARCUS
AVIATION...GEERTSON/GREIF