Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

450
FXUS63 KJKL 212330
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
730 PM EDT Tue Apr 21 2026

.KEY MESSAGES...

- A warming trend continues through Friday, with forecast highs in
  the low to mid 80s.

- Isolated to scattered showers and perhaps a storm could affect
  northern and eastern portions of the area on Wednesday.

- More widespread shower and storm chances enter the forecast on
  Friday night into Saturday and then again early next week.

&&

.UPDATE...
Issued at 730 PM EDT TUE APR 21 2026

No major changes made to the public grids aside from touch-ups
related to preparing the 00Z TAFs. The latest surface obs were
added into the latest update but otherwise, forecast remains on
track. Grids have been saved and sent.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 344 PM EDT TUE APR 21 2026

Late this afternoon shortwave ridging extended from the eastern
Gulf into the TN and Lower OH Valleys with another upper ridge
extending from western TX to CO to MT. Further norther, an upper
level trough extended from the Hudson Bay vicinity to the
Northeast Conus to near Bermuda. A shortwave trough was moving in
the northwest flow from the Great Lakes to mid Atlantic coast and
extended from the wester Great Lakes to mid MS Valley at this
time. At the surface, an area of low pressure was moving into the
western Great Lakes with a warm front southeast to near the WV and
KY border while the trailing cold front extended into of high
pressure extended to the Central Plains. Meanwhile a sfc ridge of
high pressure centered along the eastern seaboard extended into
the Southeast and Southern Appalachians. Locally, south to west
southwest flow was occurring between these systems with some
gusts as high as 20 to mph in the west and northwest. Temperatures
have risen into the 70s for most locations, but dewpoints as of 3
PM were in the upper 30s to lower 40s. This is resulting in
widespread rh in the 25 to 35 percent range as this time.

This evening through Wednesday, the shortwave trough over the
western great Lakes is expected to move southeast across the
rest of the Great Lakes and into the Northeast tonight and near
the mid to Lower OH Valleys late tonight. At the same time, the
associated sfc low will track to the upstate NY vicinity with the
warm front lifting further northeast and the trailing cold front
sagging south of the Great Lakes. This system will have limited
moisture and instability to work with as it nears the northern
portions of the area near dawn and then tracks across
Appalachians on Wednesday. The best moisture and some lift with
this system will be in the north and northeast on Wednesday.
MUCAPE per the 12Z HREF and recent RAP runs is only forecast at a
couple of hundred J/KG at best Wednesday morning and perhaps
lingering into the afternoon, though low and mid level lapse rates
could both near or perhaps excess 7C/km in the northern and far
eastern counties from the I-64 corridor southeast to Pike County
nearer to the track of the system. Moisture in these locations may
be sufficient, PW on the order of 0.8 to 1 inch for isolated to
scattered showers and perhaps a thunderstorm or two in the
morning to parts of the afternoon. The vast majority of the area
should remain dry and where rain does fall it should average just
a few hundredths of an inch. Outside of any showers or a stray
storm, rather deep mixing should result in widespread min rh
below 30 percent as the lower levels below 850 mb remain quite dry
and temperatures moderate further into the 70s to near 80.

For tonight, clear or mostly clear skies should favor deeper
valleys decoupling despite a modest south to southwest gradient.
Current dewpoints in the upper 30s to lower 40s suggest the
normally colder locations dropping back to the lower to middle
40s. A couple of upper 30s readings are not completely out of the
question. Meanwhile, behind the shortwave with the frontal zone
stalling out to the north and northeast of the area on Wed night,
sfc and upper ridging are forecast to dominate. This should lead
to another ridge valley split with low to mid 40s for valleys and
mid 50s for coalfield ridges and in areas of more open terrain.

.LONG TERM...(Thursday through Tuesday)
Issued at 415 PM EDT Tue Apr 21 2026

The long term forecast period opens on the precipice of a pattern
change here in Eastern Kentucky. The dominant Southeastern CONUS
ridging that kept the early- to mid- week sensible weather dry and
warm persists into Friday morning before a series of shortwave
troughing disturbances suppress it this weekend. As the ridging
erodes, atmospheric flow orients itself in a manner that favors more
effective moisture return. As those disturbances approach, they
introduce periodic rain chances to the forecast between Friday and
Monday and mark a shift to a more active weather pattern. While it
is true that some of this activity could come in the form of
thunderstorms, the associated rainfall will prove highly beneficial
to ongoing drought and fire weather concerns in the commonwealth.
Widespread severe storms are not expected through the remainder of
this week, but a more vigorous disturbance could lead to some
stronger storms early next week. The details surrounding that set-up
remain course at the current temporal range, but forecast confidence
is high before then.

The antecedent weather pattern favors efficient diurnal mixing on
Thursday and Thursday night. A surface high pressure system will be
traversing across southeastern portions of the CWA as a midlevel
ridge axis propagates directly overhead. Light west-southwesterly
winds will accordingly advect warm air into the forecast area, but
the continental nature of this airmass will limit the amount of
available moisture. High temperatures climb into the 80s area-wide
on Thursday afternoon, and the baseline deterministic NBM data used
to populate the long term grids is actually on the lower side of the
ensemble envelope. As such, Thursday`s highs may outperform current
expectations, and they could come close to the modeled convective
temperature thresholds. Some forecast guidance tries to develop some
diurnally driven showers in the eastern portions of the forecast,
but this appears unlikely. Modeled BUFKIT soundings at the Big
Sandy Regional airport collectively resolve a capping inversion and
stout surface dewpoint depressions during peak diurnal
heating/mixing hours. As a result, dewpoint grids were lowered
towards the NBM 10th percentile data and PoPs were decreased to
below the mentionable 15% threshold. The better PoP chances look to
remain displaced off to the NE in West Virginia, closer to the
remnants of Wednesday`s boundary.

After sunset, ridge-valley splits are favored to emerge. Conditions
look too dry for river valley fog formation, but the sheltered and
shaded valleys should quickly cool into the 40s after sunset.
Ridgetops are more likely to experience lows in the 50s, as are the
more open locales of the Bluegrass and Lake Cumberland regions.
There, surface winds should shift to more southwesterly orientation
overnight, setting the stage for the more active weather at the end
of the forecast period.

The greatest precipitation chances in the long term period look to
come in the Friday night to Saturday and Monday to Tuesday time
frames. This coincides with the ejection of better-defined shortwave
disturbances out of the Great Plains and into the Ohio River Valley.
The greatest precipitation coverage will come immediately ahead of
any associated surface frontal forcing, although isolated to
scattered warm sector convection is possible out ahead of them. The
first system lacks the amplitude and convective parameter spacing
for any of this activity to be on the stronger side, but the second
one will need to be watched more closely. SPC has outlined a Day 7
Severe Weather Outlook for portions of Kentucky on Monday, which
currently clips Wayne County. It is far too early to explore
specific details, but this activity should collectively yield much-
needed measurable precipitation across the forecast area. Storm
total QPF currently sits at over an inch for the entire CWA between
Friday and Tuesday, and the LREF resolves 65-80% probabilities for
exceeding this threshold over this same time frame. With that being
said, the weekend does not look like a total washout. Friday night`s
system has been trending quicker in recent guidance, and shortwave
ridging looks to build into the area behind it. Depending on where
the boundary stalls out, some additional activity could set up in
Southern Kentucky on Sunday, but most of the area looks to dry out
in between these two main systems. Temperatures remain seasonably
warm through the end of the period, with highs in the upper 70s and
lower 80s and lows generally in the 50s/near 60.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 730 PM EDT TUE APR 21 2026

VFR conditions are prevailing across the area as surface high
pressure is present over the area. However, as a cold front
approaches from the northwest, a low-level jet will develop
overnight and allow for LLWS through much of the overnight. As the
front gets closer, turbulent mixing will negate LLWS. Also,
increasing PoP chances are expected but mainly for KIOB, KSYM and
KSJS beginning roughly 12Z and persisting through 18Z. Once the
front moves off to the east, winds will shift to the west and
remain breezy through the afternoon but will start to diminish
with sunset.

&&

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

&&

$$

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