Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

462
FXUS63 KJKL 040100
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
900 PM EDT Fri Jul 3 2026

.KEY MESSAGES...

- Hot and humid weather persists at quite oppressive levels to
  begin the weekend.

- Isolated showers and storms are possible this evening, before
  convective coverage increases over the weekend.

- Storms through the middle of next week may produce strong to
  locally damaging wind gusts along with heavy rainfall and
  isolated instances of flooding.

&&

.UPDATE...
Issued at 900 PM EDT Fri Jul 3 2026

A better defined cluster of storms and its attendant ouflow
boundary is working its way into Wayne and McCreary Counties.
Model spread remains high, and it is unclear how long this
activity will be able to sustain itself given the waning diurnal
instability. However, the CONSSHORT is handling this set up quite
well, and in collaboration with neighboring WFOs, it was used to
update PoP, wind gust, and sky grids through the overnight hours.
Expect wind gusts up to 30mph with the outflow ahead of these
storms and then heavy rain, lightning, and gusts in the 40-55mph
range with storms developing along/just behind the boundary. These
storms have been undercut by the outflow, so they are struggling
to become as deep as they were across the state line in TN
earlier. This, plus the marginal thermodynamic/kinematic
environment, will prevent there from being much of a hail threat
and will likely limit there from being many severe (60+mph) wind
gusts. Storm chances are greatest in locations along/south of the
Hal Rogers Parkway. Ridge-valley splits and river valley fog are
expected to develop further to the NE after sunset, and any
convective activity is likely to weaken as moves to the NE of
KY-15. Fog may also develop where grounds are wet by
showers/storms, but this is contingent on any convective cloud
debris clearing after midnight.

UPDATE Issued at 636 PM EDT FRI JUL 3 2026

The forecast for this evening generally remains on track, with a
few stronger updrafts noted in recent satellite and radar
imagery. The majority of this convection will be confined to
southern portions of the forecast area, and the most robust cell
appears to be developing in Harlan County as of 615 PM. We will
need to monitor the potential for additional activity to develop
off of any outflow boundaries this evening. This convection may
produce lightning, downpours, and localized bursts of heavy
rainfall as their cores collapse and produce said outflow
boundaries. Once diurnal instability subsides after sunset, our
attention turns to potential overnight ridge/valley temperature
splits and subsequent fog development. The humid nature of the
antecedent airmass means that these splits will not be
particularly robust in magnitude, but MOS guidance indicates that
some of the typical cool spots could approach the upper 60s.
Otherwise, expect MinTs in the lower 70s. Fog coverage will be
greatest where there are nearby water sources, but if wet grounds
are realized in the wake of evening storms, fog could develop
outside of the typical valleys. Interests with outdoor evening
plans or overnight travel plans are accordingly encouraged to
stay tuned for future forecast updates and have multiple means of
receiving weather alerts.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 410 PM EDT FRI JUL 3 2026

An upper level ridge was centered near the Blue Ridge in VA into
central portions of NC this afternoon with the ridge extending
westward into eastern and central KY and east into the Atlantic.
This ridge has weakened a bit since Thursday as far as 500 heights
and has become more flattened as well as multiple shortwaves have
been moving from the Plains and upper MS Valley across the Great
Lakes and into parts of the northeast downstream of an upper
trough over the western Conus. At the surface, a ridge of high
pressure remains centered over portions of the Central to Southern
Appalachians with a frontal zone/baroclinic zone extending from
the lower St Lawrence Valley to the northern sections of the Great
Lakes to the Northern Plains. Locally forcing has been limited
with the center of the upper ridge just to the east although
MLCAPE when temperatures mainly in the 90s and dewpoints in the
70s are considered is in the 2750 to 3500 J/kg range across the
area along with low and mid level lapse rates rather steep.
Cumulus over eastern KY has been more muted compared to the
sections of the Smoky Mountains and northeast TN mountains and
sections of the Cumberland Plateau from I-40 south. The most
agitated cumulus have a times been in the vicinity of Black
Mountain though with a tendency to mix out and then reform, with
similar occurring just south in the High Knob vicinity of Wise
County.

This evening and tonight, the center of the 500mb ridge will move
east and southeast of eastern KY and into NC with a tendency of
falling heights as another disturbance moving from the Plains to
the MS Valley and nears the Lower OH and TN Valleys. Convective
allowing models have limited development over the area generally
nearer to the VA border or the TN border this evening though the
typically aggressive ARW and Fv3 have more activity nearer to the
Lake Cumberland area and I-75 west. For now have limited pops to
no more than 30 in the southwest through this evening and then
following the NBM trend of a lull overnight.

For Saturday and Saturday night, one or more shortwaves at 500 mb
should shift east across the Commonwealth while temperatures again
peak in the upper 80s to lower 90s and dewpoints remain in the
70s. Recent RAP runs suggest substantial MUCAPE on Saturday
during peak heating on the order of 4000 to 5000 J/kg with limited
shear and MLCAPE generally 2500 to 4000 J/kg. In addition, the
microburst component is elevate in the RAP around 12 or so in
portions of the area. The 18Z HRRR runs aligns with the potential
for strong downburst or outflow wind sin the south though the
recent NAM runs are a bit less impressive with instability. With
weak shear, any storms could produce torrential downpours as PW
trends upward and strong to damaging outflow winds are possible
with the strongest cells. The SPC Swody2 and the WPC ERO for Day
2 have highlighted these threats and they are included in the HWO
and social media posts and DSS Packet. A second shortwave or
outflow or evolution of upstream convection could prolong chances
for showers and storms into Saturday evening or night. Pops during
the Saturday afternoon into Saturday night timeframe were
generally in the scattered range.

.LONG TERM...(Sunday through Friday)
Issued at 406 PM EDT FRI JUL 3 2026

The long-term period opens Sunday morning with a pattern change
underway from a hot and mostly dry pattern this week to near
normal temperatures and unsettled weather for next week. The
03/12Z model suite analysis beginning at 12Z Sunday shows split
flow over the Great Lakes with troughing prevailing to the south
over the Ohio, Mississippi, and Tennessee Valleys while ridging
extends northward from the Great Lakes into northwest Greenland.
The remnants of the upper-level high that dominated this week
will have retreated to the far southeastern CONUS and out over the
Central Atlantic. Meanwhile, an ~593 dam high will reside over
the Upper Rio Grande Valley beneath a robust trough over Western
Canada. At the lower levels, the pattern is messy, though there is
likely to be some kind of a weak surface low near or over Indiana
with an associated subtle warm front extending eastward toward
the Mid-Atlantic and a decaying cold front extending back into
the Ozarks. A second weak low should be found near or over Lake
Michigan.

Heading into the upcoming week, guidance generally shows the
troughing aloft propagating eastward with time, with the southern
low fading and the more northerly low predominating and shifting
east toward the Mid-Atlantic by Tuesday and dragging a weak cold
front south of the Ohio River. As the trough and weak surface
reflection depart, that front stalls by Wednesday as heights aloft
rebound slowly. While spread increases, models suggest that the
western ridge will also break down fairly quickly by midweek as
another shallow shortwave trough (associated with the Western
Canada trough from the start of the period) drops southeast into
the Northeastern CONUS. PWATs will be seasonably moist (75th to
90th percentile relative to climo) to start the period, ranging
from 1.5 to 1.8 inches in the LREF mean on Sunday and Monday,
dropping off to around 1.5 on Tuesday as the cold front settles
through, and remains in the vicinity on Wednesday. Gradual
moisture recovery is then likely heading later in the week as the
next trough approaches. Given the synoptic features as well as
numerous weaker perturbations passing aloft, a generally unsettled
pattern is expected to persist throughout the week with diurnally
modulated convection (most widespread in the afternoon and early
evening, least widespread in the early morning) as the norm. The
driest day of the period appears likely to be Wednesday, but even
then isolated to scattered convection still appears probable.

In terms of heavy rainfall, a Marginal (level 1 of 4) ERO is in place
from Sunday through Monday night to highlight the threat of isolated
flash flooding should storms become persistent over a given location.
Temperatures through the period again start on the warm side Sunday
with highs close to 90F before settling back into the mid to upper
80s for daily highs each afternoon from Monday onward. Nighttime lows
retreat into the 65 to 70F range for most locales.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 758 PM EDT FRI JUL 3 2026

VFR conditions prevail at all TAF sites as of the 00z issuance,
but there are three distinct chances for categorical reductions
during the TAF period. Confidence in the first two meteorological
phenomena responsible for these potential reductions is quite low,
so only the third is explicitly mentioned in this TAF package.
The first is the low-end chance for CB clouds to develop off of
outflow from thunderstorms currently located to the south in
Tennessee. By the time that outflow reaches our southwestern
terminals (KSME and KLOZ), it will be working against decreasing
instability. A 15-20% chance of thunderstorms was added to the
forecast grids through late this evening, but this was not enough
to mention in the TAFs. Once that activity subsides, river valley
fog development is possible. Based on LAMP probability guidance
and model consensus, KSME and KLOZ are the TAF sites that are most
likely to experience fog-related MVFR vsby reductions, but
convective cloud debris from the evening storms to our south may
prevent this from happening. At NE terminals like KJKL and KSJS,
fog may lift out of the valleys tomorrow morning and briefly yield
reductions, but confidence in this was once again too low for an
explicit mention. Confidence is higher in the development of
scattered thunderstorms across the entire forecast area tomorrow
afternoon, so these were handled with Prob30 groups at all
terminals. Winds may become erratic and gusty in any thunderstorm
activity tonight tomorrow, but otherwise, they will remain light
and variable. Given the low-confidence nature of this forecast,
aviation interests should monitor for potential TAF amendments
later this evening and overnight.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 9 PM EDT Saturday for KYZ044-050>052-058>060-
068-069-079-080-083>085.

Extreme Heat Warning until 9 PM EDT Saturday for KYZ086>088-104-
106>120.

&&

$$

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