Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

711
FXUS63 KJKL 211354
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
954 AM EDT Sun Jun 21 2026

.KEY MESSAGES...

- Mainly dry weather is expected through this afternoon.

- Showers and thunderstorms will make a return this evening or
  overnight tonight and Monday, possibly bringing heavy rainfall
  along with strong wind gusts.

&&

.UPDATE...
Issued at 954 AM EDT SUN JUN 21 2026

Mid morning observations have been blended into the forecast,
including less cloud cover initially.

UPDATE Issued at 627 AM EDT SUN JUN 21 2026

There are no changes to the forecast. Hourly T/Td grids using the
latest hourly observation as the initialization for the forecast.

&&

.SHORT TERM...(Today through Monday)
Issued at 250 AM EDT SUN JUN 21 2026

An unusually active jet stream persists across the Ohio Valley
through the short-term period. A weak disturbance will exit the area
to the east this morning within west-northwesterly flow aloft, with
a weak front near the I-64 corridor having served as a focus for
isolated shower and thunderstorm development last evening into the
overnight.

Progressive shortwave ridging moves across the area today ahead of
the next disturbance which will push increasing moisture northeast
across much of eastern KY later today into the overnight tonight.
PoPs increase from the west this evening into the overnight, but
there is considerable uncertainty on location, magnitude, and timing
of any MCS activity that is likely to be traversing the Ohio River
Valley, with some models depicting little if any precipitation and
other models depicting a very active overnight period with multiple
rounds of showers and thunderstorms. Have thus opted to stick pretty
close to the NBM with regards to PoPs and QPF.

If convection were to enter the area from the west tonight, there is
a Marginal Risk for severe storms, with damaging winds the primary
threat. Storms would likely weaken as they outrun better low-level
moisture and instability as they move east into far eastern
Kentucky, but would still pose a threat for excessive rainfall, with
a Slight Risk remaining for our far northern counties late tonight
and a Marginal Risk for adjacent areas to the south and east.

Additional disturbances move east from the center of the country
toward and across the OH/TN Valleys Monday into Monday evening, with
a surface low traversing eastward just north of the Ohio River
and an accompanying cold front extending southwest through
Kentucky into Tennessee. Strong moisture advection in the low
levels of the atmosphere will allow for an increase in instability
into eastern Kentucky, setting the stage for numerous to
widespread thunderstorm activity through the daytime period,
peaking in the afternoon through early evening before diminishing
with the passage of the cold front. A few of these storms could be
on the strong side, with damaging winds again the primary threat.

A Flash Flood Watch was considered with this forecast package for
all or part of the tonight through Monday period, but ultimately
not issued (at least for now) owing to the considerable
uncertainty with regards to convective activity tonight and
Monday. This may need to be revisited later today should models
allow for better clarity on the forecast details during this time.

.LONG TERM...(Monday night through Saturday)
Issued at 1246 AM EDT Sun Jun 21 2026

When the long term forecast period opens on Monday evening, there
will likely be ongoing showers and thunderstorms across Eastern
Kentucky. As discussed above, this lingering convection may
initially pose a risk for gusty winds and heavy rainfall. However,
the intensity of this activity is poised to decrease after sunset.
The loss of diurnal heating and rain-cooled air will combine to
reduce instability to below favorable values. This, in turn, should
allow rainfall rates to wind down overnight, with only light showers
remaining in SE KY by Tuesday morning.

The parent cold front looks to finally clear the entire CWA by
midday Tuesday. A shortwave trough axis propagates into the southern
Appalachians in this time frame and places Eastern Kentucky in a
vertically stacked northwesterly flow regime. Orographic lift could
yield a few additional sprinkles in the higher southeastern terrain
on Tuesday afternoon, but midlevel height rises and the advection of
a cooler and drier airmass into the area should prevent any
additional impacts. Expect seasonably cool afternoon highs in the
upper 70s behind the boundary under clearing skies, which will then
favor overnight ridge-valley temperature splits into Wednesday
morning. Given the recently wet grounds, expect nocturnal radiation
fog to form in at least the conventional river valleys. That fog
should burn off as the sun rises on Wednesday, which will be a
pleasant summer day under the influence of a postfrontal surface
high pressure system.

The flow aloft returns to a progressive quasi-zonal flow regime by
midweek, with passing shortwave disturbances triggering occasional
precipitation chances. As the aforementioned surface high shifts
east into Thursday, southwesterly wind components reintroduce warm
air advection and moisture return to the column. Highs accordingly
return to the mid/upper 80s through the remainder of the period, but
increasing model spread regarding the timing and amplitude of those
late period impulses makes it difficult to pinpoint precipitation
forecast details. PoPs are accordingly relegated to below the 50%
mark in the blended forecast guidance used to populate the long term
grids, and it may be more reasonable to describe this shower/storm
activity with isolated/scattered coverage wording. In other words,
expect typical summertime weather conditions towards the end of the
long term forecast period.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 720 AM EDT SUN JUN 21 2026

Outside of any valley fog lingering through ~13z this morning, VFR
conditions will prevail into tonight. Uncertainty arises after
02z Monday as to the magnitude, location, and timing of upstream
convection which may move toward or through the area before the
end of the TAF period. KIOB and KSYM would be most likely to first
see such activity, perhaps as early as 02z, with the remainder of
TAF sites having the possibility of convection before the end of
the TAF period. The uncertainty in the forecast warrants coverage
with primarily PROB30 groups.

Winds will be light and variable or south to southwest at 7 kts or
less through this afternoon, but will begin to increase this
evening into the overnight as a cold front approaches from the
west. A low-level jet will also develop, and may produce localized
LLWS, especially after 06z tonight.

Light winds overnight will trend southerly to southwesterly at 7
kts or less during the afternoon hours, and will likely continue
into the late evening at more exposed locations such as KSME and
KIOB.

&&

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

&&

$$

UPDATE...HAL/CMC
SHORT TERM...CMC
LONG TERM...MARCUS
AVIATION...CMC