Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

316
FXUS63 KJKL 262013
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
413 PM EDT Sun Apr 26 2026

.KEY MESSAGES...

- A more active weather pattern will set up this week, with
  multiple chances for widespread showers and storms from Monday
  night through Wednesday.

- Severe weather potential remains masked by forecast uncertainty
  here in Eastern Kentucky, but a stronger line of storms is
  poised to approach the I-75 corridor early on Tuesday morning.

- Additional thunderstorms are possible later on Tuesday and again
  on Wednesday, and these will bring highly beneficial rainfall to
  the region.

- Once a frontal boundary finally clears the area late next week,
  cooler than normal temperatures are favored.

&&

.SHORT TERM...(This evening through Monday night)
Issued at 413 PM EDT SUN APR 26 2026

Seasonably mild temperatures are noted across eastern Kentucky this
afternoon -- thermometers range from the upper 60s in the northern
foothills to lower and middle 70s elsewhere under mostly sunny skies
and light, cool northeast winds. Surface ridging dominates over
the Ohio Valley from an extensive area of high pressure over the
Great Lakes and Eastern Canada. This is supported aloft by a 500
hPa ridge axis extending from the Mid-Mississippi Valley northeastward
to over Northern Quebec. An upstream trough is noted over Central
Canada and much of the Western CONUS and will be responsible for
our next notable weather.

The quiet weather will persist tonight and Monday as the ridging
shifts east of the Appalachians. This will yield mostly clear skies
tonight across the area (just a few passing high clouds) with
temperatures dipping back into the upper 40s to mid 50s for most
locations. A few of the typically colder northern hollows could
briefly dip into the mid 40s. Some patchy fog formation is
possible in the deeper sheltered Coalfield river valleys as well.
Southerly return flow will develop late in the night and continue
on Monday, ushering in noticeably milder air. Temperatures at 850
hPa rising into the 13 to 15C range should support afternoon highs
rising into the lower to mid 80s for most of the area under mostly
sunny skies.

By Monday evening, ridging will be departing as a leading shortwave
(within broader parent troughing) shifts across the Upper
Mississippi Valley and supports a deepening low pressure system
tracking from Wisconsin into north-central Ontario. Convection,
some of it strong to severe, is modeled in the CAMs to develop
over the Central Plains today within the system`s warm sector and
propagate eastward into the Mid-Mississippi and lower reaches of
the Ohio Valley on Monday. This convection, as well as additional
convection firing ahead of the system`s cold front, should
congeal into a QLCS structure and race eastward Monday night,
outrunning its parent forcing and eventually its instability
source as it moves from Central into Eastern Kentucky. As a
result, we can expect a weakening line of showers and
thunderstorms, likely with a period of trailing stratiform
precipitation, to quickly move across eastern Kentucky during the
early morning hours on Tuesday, likely bringing a widespread
0.25 to 0.50 inch rainfall. (Of note, a few isolated weaker
showers cannot be ruled out earlier Monday evening, especially
near and north of I-64 amidst increasing low-level warm air and
moisture advection.) SPC has maintained a Marginal Risk (1 out of
5) for severe weather across the northwestern two-thirds of the
CWA on Monday to account for the potential for isolated damaging
wind gusts with this QLCS. Also, temperatures on Monday night
will be milder than tonight, generally in the mid 50s, as mixing
should continue through the night amidst a 3-4+ mb surface
pressure gradient across the CWA.

.LONG TERM...(After midnight Monday night through Saturday)
Issued at 924 AM EDT Sun Apr 26 2026

The brief ridge of high pressure over the Ohio Valley will be
squeezed out of the area Monday night into Tuesday. Relatively
quieter weather during the daytime hours on Monday becomes more
active overnight, with showers and thunderstorms initiating in
Western Kentucky on Monday evening. As these storms progress east,
they may organize into a QLCS.

Strong southwesterly winds ahead of the line will be bolstered by
a 50-60 knot LLJ in advecting moisture into the column. LREF
PWATs from the 12Z ensemble run climb up towards the 1.2-1.3 inch
range by the time the line arrives on Tuesday morning. Model wind
profiles suggest the better sheared environment is in the
northwestern 2/3 of the CWA by Tuesday morning. SPC has issued a
Day 2 Marginal Risk for severe weather for these parts of the
forecast area. That outlook is valid from 12Z Monday morning to
12Z Tuesday morning, but our primary concern is for after 04z
(midnight) Tuesday morning. This outlook primarily exists for
locally damaging thunderstorm wind gust potential, but the most
likely solution is that a weakening line of storms becomes
elevated in nature as it approaches the I-75 corridor. The most
favorable ingredients for severe weather remain displaced to the
NW of Eastern Kentucky during this first wave of storms, but
regardless, we will be closely monitoring the evolution of the
upstream convection on Monday evening.

Tuesday`s forecast will depend on the evolution of that overnight
convection. The surface cold front is expected to stall out to
our northwest on Tuesday, which has prompted an increase in the
day`s temperature forecast. With the strong LLJ out the southwest
bringing warm moist air into the area through Monday night,
overnight temperatures are expected to remain elevated in the
upper 50s to low 60s. Breezy prefrontal southwesterly winds will
remain in place across most of the forecast area into the evening
hours. This allows afternoon highs to climb towards the upper
70s/lower 80s again, especially in SE KY. With southwesterly winds
remaining through Tuesday, dew points rise into the upper 50s/low
to mid 60s through the afternoon. However, lingering cloud cover
and remnant outflow/differential heating boundaries could yield
mesoscale temperature gradients across the CWA. These smaller-
scale details are difficult to pinpoint at the current temporal
range, but current forecast thinking is that a locally favorable
corridor for a second round of storms will emerge in Southern
Kentucky on Tuesday afternoon and evening.

LREF mean soundings across southern Kentucky at 8pm Tuesday
evening resolve approximately 1000 J/kg of CAPE and 40 knots of
effective bulk shear. The related hodographs are curved in the
lower levels and elongated, suggesting that all convective hazard
types are possible. SPC has accordingly denoted a Slight (2/5)
Risk for severe weather in portions of the CWA to the west of I-75
on Tuesday. Confidence in severe weather is highest there, and
ML/AI/Analog guidance gives credence to this notion. A Marginal
(1/5) Risk has been outlined for the rest of the CWA, largely due
to the conditional nature of the risk and compounding forecast
uncertainty. Interests across the entire forecast area should monitor
for updates, as adjustments to the outlooked areas are likely as
the details of the set-up come into focus.

An active baroclinic zone looks to set up through midweek, and
a third round of convection may materialize on Wednesday. As
guidance trended slower with Monday`s first wave of activity, then
stronger with Tuesday`s second, it has also collectively kept the
parent boundary in the vicinity of the forecast area on
Wednesday. With quasi zonal flow aloft, the forcing for any
additional midweek storms lies in mesoscale details that are hard
to pinpoint at the extended temporal range. However, the 12z LREF
ensemble data suggests that there may be conditionally favorable
parameter spacing for another round of stronger thunderstorms on
Wednesday. The likely stationary nature of the frontal boundary
and long/straight ensemble mean hodographs mean that this risk is
likely marginal, but yesterday`s 12z deterministic models placed
Eastern Kentucky in the vicinity of the left exit region of a
zonal 300mb jet streak around the base of a digging upper level
trough. If the resultant synoptic lift overlaps with the warm side
of that boundary and mesoscale convective enhancements within our
CWA, some stronger (potentially splitting) cells cannot be ruled
out. At the very least though, this set up will lead to some
highly beneficial rainfall.

Storm total QPF from Monday evening through Wednesday night
generally sits between 1.10 inches in the Northeast/Big Sandy Basin
to 1.70 inches in the vicinity of Lake Cumberland. The model blend
used to populate these grids currently sits outside of the temporal
range of the higher-resolution CAMS, so expect more spatial
variability and the potential for locally-enhanced totals in the
final storm total QPEs. The LREF Ensemble probabilities generally
follow the same lower to higher NE to SW gradient when it comes to
receiving at least 1 inch of measurable rainfall over that 60 hour
time frame. The highest exceedance probabilities (around 75%) are
currently in the Cumberland River Basin, with values closer to 55%
in our northeastern counties. Given that the KJKL and KLOZ climate
record sites are both currently below their climatological rainfall
averages for the month of April and the year to date, this rain is
welcome to fall. Given the potential for convectively-enhanced
higher amounts and the signal for multiple rounds of convection, WPC
has placed southern counties in a Marginal (Level 1/4) Excessive
Rainfall Outlook. The dry ground should be able to soak most of this
rainfall up, and widespread river flooding is unlikely in the
various hydro ensembles, but nuisance-type ponding of water is
possible in the typical areas of poor drainage. Ideally, all of this
activity is able to put a dent in the widespread D1 (moderate) to D2
(severe) drought currently observed across Kentucky.

Deeper mid to upper level troughing digs into the Ohio River Valley
headed into the weekend. Strengthening WNW flow aloft will work to
advect a cool, continental airmass into the forecast area, and the
aforementioned, stubborn frontal boundary is poised to finally shift
out of the CWA on Thursday. Precipitation chances and sky cover
tapers off as drier air filters in throughout the column; they give
way to highs in the 60s and lows in the 40s. These readings are
below climatological norms for Eastern Kentucky at the end of April,
and reinforcing shots of colder air arrive in the region as
shortwave disturbances rotate around the base of the broader
troughing to kick off the month of May. While these disturbances may
yield additional precipitation chances, increasing model spread
makes it difficult to pinpoint timing and magnitude details.
Guidance previously depicted a southern stream system brushing the
CWA next weekend, but the 12z suite backed off this idea. The time-
lagged NBM ensemble smooths out the PoPs related to that system and
the troughing perturbations into low end chances to close out the
forecast period, but the more impactful sensible weather is likely
to be observed on the thermometers at the start of may. The
overarching synoptic pattern favors below normal temperatures for
the first days of May, potentially reaching much below normal
readings on May 2nd and 3rd. The CPC extended-range hazard outlook
is centered on these colder temperatures due to their potential to
cause a frost, and their 8-14 day temperature outlook highlights a
50-60% chance of below normal temperatures across the greater Ohio
River Valley. Those with interests sensitive to frost (such as
agricultural crop producers or recreational gardeners) are
encouraged to monitor for updates as the calendar turns to May.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 148 PM EDT SUN APR 26 2026

VFR conditions should prevail through TAF period. A few shallow cu
are possible this afternoon; otherwise, expect mainly high clouds
at times. Fog is possible tonight in the most sheltered river
valleys but is not expected to impact the TAF sites. Winds will
generally be light and variable at less than 10 kts through
tonight before becoming southerly at 5 to 10 kts after 14Z on
Monday.

&&

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

&&

$$

SHORT TERM...GEERTSON
LONG TERM...MARCUS
AVIATION...GEERTSON