Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

366
FXUS63 KJKL 250036 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
836 PM EDT Wed Jun 24 2026

.KEY MESSAGES...

- Lower humidity and dry weather continues through Thursday
  morning.

- Unsettled weather returns to end the week and into the weekend,
  with rounds of showers and storms possibly producing heavy rain
  and a flood threat.

- An extended period of hot temperatures begins Monday with high
  temperatures reaching into the low to mid 90s and heat indices
  nearing or exceeding 100 degrees.

&&

.UPDATE...
Issued at 815 PM EDT WED JUN 24 2026

Some high based cumulus lingers across the southern counties with
cirrus passing overhead. Skies should again be clear or mostly
clear of low and mid level clouds tonight and fog should again
form in the valleys as high pressure begins to depart. The
ridge/valley split forecast appears on track so at this point only
freshened up hourly temperatures over the next few hours.

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 530 PM EDT WED JUN 24 2026

A post-frontal surface high pressure system passes through the Ohio
River Valley through the short term forecast period and yields
pleasant early summertime conditions across most of Eastern
Kentucky. Light/variable winds and partly cloudy skies will continue
through sunset, with a field of diurnal cumulus clouds draped around
the eastern edge of this system. Upstream in Central KY, a drier
airmass directly underneath the center of the system leaves only
cirrus-type high clouds visible on satellite imagery. Given the
quasi-zonal flow aloft, this feature and those conditions are
progged to propagate east into the CWA tonight. Once the high is
directly above our heads, subsidence and the loss of diurnal heating
will favor a clearing trend. Some of the thinner high clouds may
stick around tonight, but this will not be enough to prevent
overnight ridge/valley temperature splits.

After sunset, the cooler sheltered/shaded valleys across the region
should quickly drop into the 60s from late afternoon MaxT readings
in the upper 70s/lower 80s. Temperatures there will bottom out in
the 50s by morning under conditions favorable for efficient
radiational cooling. Given antecedent dews in the upper 50s/near 60,
this should be sufficient for valley fog formation. Fog is most
likely along the main stem rivers and bigger creeks/streams, where
proximity to a water source will bolster and sustain development.
Any fog that develops will lift up towards the ridges towards dawn
tomorrow morning and then burn off as the sun`s influence grows.

Low level flow turn west-southwesterly on the backside of that high
tomorrow. Expect surface winds to be a bit breezier than in recent
days, with gusts in the 15-20 mph range possible during peak diurnal
mixing. The resultant warm air advection will combine with solar
insolation to produce highs in the mid/upper 80s by tomorrow
afternoon. Dewpoints creep up into the lower half of the 60s in this
same time frame, with the highest values (around 65) in the
Bluegrass counties. This area of relatively greater moisture
overlaps with modeled convective temperatures in the mid to upper
80s range. Therefore, the cu field that develops tomorrow afternoon
will have a better chance at producing precipitation than today`s. A
few updrafts could take advantage of favorable synoptics aloft to
deepen into cumulonimbus clouds. Models collectively resolve a 70-90
knot 300mb jet streak passing to the base of a shortwave trough to
the north of the Ohio River tomorrow evening. While most of our CWA
will be displaced from these features and thus under the influence
of the antecedent surface high, slight chance PoPs have been
introduced to the I-64 corridor tomorrow evening and night. SPC
clips Fleming County with a Marginal Day 2 Severe Weather Outlook,
but with less than 1500 J/kg of CAPE and only modest (30 knots) of
bulk shear, isolated and sub-severe thunderstorms are more plausible
within our CWA. We will have to monitor radar imagery and upstream
convective evolution closely though, as activity closer to these
features could propagate towards our northern counties overnight.

Depending on the magnitude of the cloud cover from any ongoing or
upstream activity around sunset on Thursday night, another night of
topographic temperature splits looks likely. Thicker, more
widespread cover could insulate localized areas in the Bluegrass,
but SE KY is more likely to remain under the influence of the
surface high positioned over the Appalachians. That ridging should
suppress meaningful convection across the southeastern 2/3 of the
CWA tomorrow and consequentially leave skies mostly clear after
dark. Thus, expect the hollows and valleys of SE KY to quickly cool
off into the 60s once again after sunset and for valley fog to
subsequently develop. If this decoupling comes to fruition, any
upstream activity would likely be moving into a stable, less
favorable environment for sustained/organized convection on Thursday
night. Additional rain chances arrive by Friday morning, and the
more active start to the long term forecast period is accordingly
discussed below.

.LONG TERM...(Friday through Wednesday)
Issued at 333 PM EDT WED JUN 24 2026

The long-term period opens at 12Z Friday with quasi-zonal flow
and embedded shortwaves across the Ohio Valley and adjacent
regions. This is mirrored at the surface by a weak wave of low
pressure near/over Lake Ontario with a frontal boundary trailing
southwestward to another weak low over Missouri, and then
southwest to another weak low in the vicinity of the Oklahoma and
Texas panhandles. This leaves eastern Kentucky residing in the
warm sector. Well upstream, a much more substantial trough axis
extends from the Alaska Panhandle southward to along the
California coastline.

The pattern will change only slowly on Friday and Saturday, with
the quasi-zonal flow over our region gradually giving way to an
emerging ridge over the Mississippi Valley being pumped up in
response to the upstream trough digging deeply and closing off
into a deep upper low over the Pacific Northwest. In response, the
surface frontal boundary will tend to lift northward across the
Plains states while simultaneously settling southward on the
eastern side of the Appalachians, leaving the Mid-Ohio Valley as
the pivot point for the boundary. Multiple upper-level
perturbations aloft combined with 1.6 to 1.9 inch PWATs (LREF
mean) and diurnally modulated instability (generally peaking in
the 1,000 to 2,000 J/kg of MUCAPE each afternoon) will keep the
threat of showers and thunderstorms in the forecast with the
accompanying threat of torrential downpours. The overall flow,
though modest, should be strong enough to keep individual
convective cores progressive, but the repeated rounds of
convection, focused by the nearby frontal boundary, could lead to
locally excessive rainfall. This risk is noted in the Day 3 WPC
ERO Slight Risk over northwestern portions of the CWA on Friday
(Marginal Risk further southeast) and then a Day 4 ERO Slight Risk
for nearly all of the CWA on Saturday. Synoptically, shear is
rather weak, which, combined with limited instability, is likely
to keep the threat of any severe weather low. However, modest
mesoscale kinematic enhancement near the frontal boundary might
support slightly better convective organization in the northern
and eastern counties closer to the front.

The frontal boundary will become more north-south oriented and
situated to our east by Sunday as upper-level ridging strengthens
further into a closed high over the Lower Mississippi River Valley.
One more day of scattered to numerous showers and thunderstorms can
be expected again on Sunday as the front remains nearby. That
boundary then lifts northeast heading into the new work week with the
center of the upper-level high drifting up into the Mid-Mississippi
Valley. This will keep high humidity in place from Monday through
through the end of the period, but the rising heights will tend
to lead to some mid-level capping. LREF mean PWATs are in the 1.5
to 1.6 inch range during this period. Robust CAPE (2,500 to 3,500
J/kg) formation is modeled each afternoon, largely trapped by the
capping inversion. However, differential heating over the rugged
Coalfield topography (with the Cumberland Mountains and Pottsville
Escarpment being the most notable focusing topographic features)
may be sufficient to break the cap and yield isolated to scattered
afternoon and evening pulse thunderstorms. With weak flow and
mid-level dry air in place, it does appear that there is a risk
for a few of the most robust cores to produce strong to severe
microburst winds as they collapse. Temperatures will also be hot,
with LREF mean 850 hPa temperatures reaching 21 to 22C on Monday,
around 22C on Tuesday, and 22 to 23C on Wednesday. Probabilities
for temperatures exceeding 90F across the lower elevations are in
the 50 to 70 percent range on Monday, 60 to 90 percent range on
Tuesday, and 70 to 90 percent on Wednesday. The heat combined
with dew points in the low to mid 70s should support heat indices
nearing and in many cases exceeding 100F from Monday afternoon
onward.

In sensible weather terms, look for occasional rounds of showers and
thunderstorms, some of which could produce heavy rainfall and
instances of flooding, on Friday and Saturday, becoming less numerous
on Sunday. It will be mild and muggy with highs in the low to mid 80s
on Friday and Saturday, warming into the 85 to 90F range for
Sunday. During that time, nighttime forecast lows range within
several degrees of 70F. From Monday onward, it will be hot and
steamy with temperatures soaring into the low to mid 90s each
afternoon while nighttime lows stay mostly in the 70s. Isolated to
scattered showers and thunderstorms will be possible each
afternoon and may bring localized relief from the heat for some.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 825PM EDT WED JUN 24 2026

Lingering cumulus in the south should gradually dissipate over the
next hour or two and give way to mainly just passing cirrus/high
clouds overnight. With departing high pressure in control, conditions
are primed for river valley fog formation after 04Z with reductions
to MVFR and IFR if not locally lower, but this is still not expected
to affect any of the TAF sites. In general, expect light and
variable winds and non- impactful sky cover to persist into tomorrow
morning. Winds become more southwesterly around 15Z and after and
strengthen into the 5 to 10KT range. Also,between 15Z and 18Z, when
another cu field is expected to develop in the 4 to 6kft agl range
though VFR conditions will persist.

&&

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

&&

$$

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