Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

491
FXUS63 KJKL 180650
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
250 AM EDT Mon May 18 2026

.KEY MESSAGES...

- Very warm and mainly dry weather will persist through Tuesday
  afternoon.

- Showers and thunderstorms enter the forecast late Tuesday into
  Tuesday night, then persist through next weekend.

- The switch to a wetter pattern yields temperatures closer to
  normal readings and produces a highly-beneficial, widespread wetting
  rainfall.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 249 AM EDT MON MAY 18 2026

Seasonably hot and dry weather is expected into Tuesday as the
area resides on the western/northwestern periphery of a strong
cut-off mid-level high situated over the Carolinas, a narrow
westward extension of the Bermuda High. High temperatures are
forecast to reach the upper 80s to lower 90s both days, with an
increase in high clouds Tuesday as a cold front begins to move
toward the area. Low-end PoPs are introduced Tuesday afternoon
for some areas from the west, but a clear trigger for the
marginal instability that is likely to exist at that time is not
readily apparent giving the continued warm mid-level temperatures
through early evening Tuesday.

.LONG TERM...(Tuesday night through Sunday)
Issued at 249 AM EDT MON MAY 18 2026

The long term forecast period opens on the precipice of a pattern
change. A series of shortwave disturbances moving around the
northwestern periphery of the previous days` amplified SE CONUS
ridging will gradually work to break this ridge down. As this
happens, flow in the lower half of the column adopts a more
southwesterly orientation. This translates to increased moisture
return and increasing sky cover into Tuesday night.

A frontal boundary arrives from the northwest on Tuesday night, and
its forcing should be sufficient to spark additional showers and
storms. The question is - how does the thermodynamic environment
look ahead of this feature? Given the boundary`s nocturnal arrival
in our portion of the Commonwealth, temperatures and instability
*should* be at their diurnal cycle minimum. However, the persistence
of SW low level flow and the antecedent warmth will leave Tuesday
night`s surface temperature insulated well above climatological
averages. Expect lows to remain above the 60 degree mark, with some
of the warmer ridgetops potentially hovering around 70. Depending on
the amount of sky cover present around sunset, valley locales could
thermally decouple and experience efficient radiational cooling.
This could yield a scenario in which upstream convection becomes
elevated above a more stable boundary layer in the valleys once it
reaches our CWA`s western escarpment. In other words, we are on QLCS
graveyard watch for Tuesday night into Wednesday morning.

Regardless of the strength of this convection, it will provide some
highly beneficial widespread rainfall to eastern Kentucky. There is
a 65-75% chance for at least a quarter of an inch of rain in the 24
hour period ending at 8pm Wednesday across the entire forecast area.
The greatest chances and the greatest storm total QPF will fall
across the Cumberland River Basin, which is also subsequently where
some of the most impactful drought is also in place in the state -
so any precipitation will be well received. While the boundary
has trended a little bit more progressive with this morning`s
forecast guidance suite and storm total QPF has ticked a bit down,
the boundary will struggle to fully push into the ridging in the
SE CONUS. It is poised to stall out in the Tennessee Valley by
midweek, and thus the southern half of the commonwealth will see
repeated rain chances through the end of the period. Given these
trends, Wednesday`s Marginal (Level 1/4) Excessive Rainfall
Outlook was trimmed down to just the Lake Cumberland region with
the afternoon update. The entire Cumberland River Basin remains
outlooked in a Marginal ERO for Thursday, as that boundary looks
quite stubborn. Widespread, significant flash flooding is still
not the most likely forecast solution, but areas where multiple
rounds of thunderstorms persist for multiple days will need to be
monitored closely as the ground progressively saturates. Again,
this will likely be more beneficial than anything for the rain
deficit in this region.

On the north side of the boundary, post-frontal winds will work to
advect a cooler and drier airmass into portions of the area.
Northern portions of the forecast area should cool into the upper
70s on Wednesday, and more recent guidance suggests that
Wednesday`s MaxT grids could actually trend downward in future
forecast packages. Temperatures then cool to the 70s area-wide on
Thursday. Unfortunately this reset back to cooler weather is
short-lived. The same boundary that stalled to our south will then
lift back north as a warm front on Friday, leaving much of
eastern KY in the warm and unstable sector through the weekend as
another surface low passes across the Ohio Valley. In addition to
more warm air advection, it will also advect moisture into the
region, resulting in heightened rain chances from Friday through
Sunday. This second, potentially more active pattern bears
watching for agricultural and hydrological interests, though. The
LREF Grand Ensemble resolves a 70-90% chance of at least 1 inch of
precipitation across the entire CWA by Saturday night, with more
expected on Sunday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 120 AM EDT MON MAY 18 2026

A bit of valley fog will likely affect some locations with IFR or
worse conditions late tonight and early Monday morning, but it is
not expected to affect any of the TAF sites. Otherwise, VFR
conditions will hold through the period along with winds less than
10 kts generally from the south through 12z-14z. However, LLWS
likely impacting western sites will gradually diminish from south
to north through the overnight. Southwest winds at 6 to 12 kts
sustained develop between 14z-16z, with max gusts reaching as high
as around 20 kts in the afternoon during peak heating, before
diminishing significantly again toward sunset. Some models develop
marginal south-southwesterly LLWS again briefly in the mid to
late evening, but with low confidence, and with it appearing to be
very transitory if it does occur, will opt to leave this out of
TAFs for now.

&&

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

&&

$$

SHORT TERM...CMC
LONG TERM...JMW/MARCUS
AVIATION...CMC