Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

771
FXUS63 KJKL 182050
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
450 PM EDT Mon May 18 2026

.KEY MESSAGES...

- Very warm and mainly dry weather will persist through Tuesday
  afternoon.

- Showers and thunderstorms enter the forecast late Tuesday into
  Tuesday night, then persist through next weekend.

- The switch to a wetter pattern yields temperatures closer to
  normal readings and produces a highly-beneficial, widespread wetting
  rainfall.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 435 PM EDT MON MAY 18 2026

Late this afternoon an upper level ridge extended from the
Southern Appalachians across the Carolinas to near Bermuda and
another upper ridge was centered in the Gulf. Meanwhile an upper
trough extended from Central Canada across Alberta and
Saskatchewan to the Four Corners vicinity to the Southwest Conus.
A couple of shortwaves were moving around the ridging and across
sections of the mid MS Valley and the Lower OH Valley while a more
substantial shortwave was working across sections of the Central
Plains. At the surface, a ridge of high pressure extended from the
Atlantic into parts of the Southeast and Southern Appalachians
while a wavy frontal zone extended from the Northeast across
sections of Quebec and Ontario to the northern and western Great
Lakes to the Central Plains to Southwest Conus. Cumulus have
developed during the heat of the day and temperatures are mild
averaging between 10 and 15 degrees above normal highs for this
time of year.

Tonight and Tuesday, upper level ridging is expected to remain in
place from near or north of Bermuda across the Southeast and into
the Gulf. At the same time, a shortwave trough is expected to move
across sections of the Central an Northern Plains and into the
western Great Lakes through Tuesday morning and then to the
Central Great Lakes through the remainder of the day. A general
trend of rising 500 mb heights is expected through tonight with
near neutral tendencies on Tuesday morning and then some height
rises for the afternoon to early evening. Further 500 mb height
falls are anticipated to end the period as the upstream shortwave
moves to the eastern Great Lakes to Lower OH Valley. At the
surface, the high pressure ridge will build into the Southern
Plains tonight, before shifting to the south and southeast to end
the period. As this occurs a sfc low tracks from the Plains across
the Great Lakes and eventually to Ontario and Quebec while the
trailing cold front will move into the Northeast and sag across
sections of the OH Valley and into eastern KY.

Dry weather should prevail through at least midday on Tuesday
with the pattern favoring a modest ridge/valley split and
temperatures in the coldest locations could fall a couple of
degrees below the current forecast based on trends from last night
and some mixed dewpoints near the 60 degree mark versus the lower
60s. Valley fog along the larger creeks, rivers, and lakes should
form around or near midnight and then dissipate toward 9 AM EDT.

With height falls on Tuesday afternoon, some convection cannot be
completely ruled out during peak heating in the northwest half of
the CWA and it is possible a larger areal extent of slight chance
pops may ultimately be needed. Any stronger storm could produce
gusty winds as there are some stronger gusts in the 18Z HRRR with
some of the activity near peak heating. Better chances arrive
later Tuesday evening and especially Tuesday night as the height
falls continue and the front nears eastern KY.

.LONG TERM...(Wednesday through Monday)
Issued at 343 PM EDT MON MAY 18 2026

If the long term period could be summarized with just one word, it
would be wet. The period will open with broad ridging over the
southeastern US and troughing over the Hudson Bay. This will leave
Kentucky in a regime of generally southwesterly flow aloft at the
onset of the long term period. At the surface, a cold front will
extend through the CONUS from a surface low centered over Quebec
and push into eastern Kentucky on Wednesday, although the exact
timing of the frontal passage remains dependent the upstream
evolution of this system. The environment ahead of the front will
be moist (owing to prefrontal southwesterly winds), but
instability will be dependent on whether the timing of the frontal
passage can align with maximal daytime heating. Accordingly, LREF
guidance still shows a wide range of MUCAPE values, but the most
likely outcome at this time is that instability should be
sufficient for a few thunderstorms. Given that wind shear is
expected to be meager, widespread organized severe weather appears
unlikely. A few machine learning sources have introduced very
low-end probabilities for gusty winds Wednesday afternoon, but
this threat remaining highly conditional on favorable frontal
timing, and thus confidence remains very low in this outcome.

Regardless of storm strength, this system will bring much-needed
rain to eastern Kentucky, which currently remains in drought
(ranging from D1 conditions in our eastern forecast area to D2 and
a pocket of D3 conditions in the western portion of forecast
area). With broad ridging over the southeastern CONUS, the
aforementioned cold front will struggle to push through into the
Atlantic coast states and likely stall over the periphery of the
ridge going into Thursday (TN area) before lifting into Kentucky
again as a warm front on Friday. This pattern will bring multiple
rounds of rain to the forecast area. As such, WPC has introduced
multiple Marginal (Level 1 of 4) Excessive Rainfall Outlooks for
the forecast area; one for our entire area on Wednesday, another
for the Lake Cumberland area on Thursday, and a third for our
entire forecast area again on Friday. QPF does not look overly
impressive on any given day; LREF guidance shows that the chance
of exceeding 0.5 of rain on any given day is low to moderate
(maxing out at around 50% on Wednesday). However, this does not
account for enhanced rain rates in any thunderstorms that do
develop. If storms track over the same area for multiple days in a
row, isolated instances of nuisance flooding cannot be ruled out.
This is especially true closer to the KY/TN border, which will
feel the greatest impacts of the stalling front. However, these
details will need to be refined in the short term when convective
rain rates can be better accounted for.

Thursday looks to be the coolest day of the period. Following the
frontal passage, CAA via postfrontal winds will keep maxTs
generally below normal, with a defined thermal gradient over our
forecast area as the front stalls. Currently, the NBM is
outputting highs in the 80s for the southern portion of our
forecast area; however, this appears to be an outlier compared to
other guidance, so maxTs were bumped down a few degrees on
Thursday afternoon to better account for the frontal passage.
After the front lifts northward again, flow will become more
southerly, and temperatures will be warmer than on Thursday. The
NBMs highs in the upper 70s and low 80s may be slightly overdone
given that rain is likely going into Friday afternoon (80-90%
chance), but highs do represent an expected warming trend as the
warm front lifts northward. Unfortunately (for outdoor activities)
or fortunately (for drought relief), this weekend also looks to
be quite wet even as the original front exits our area. A slow-
moving upper level trough over the central CONUS, in addition to
potential embedded impulses, will allow for rain chances every day
through the weekend and into the end of the period.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 235 PM EDT MON MAY 18 2026

VFR conditions are expected to prevail through the period. The one
caveat will be valley fog between 04Z and 13Z with some MVFR and
IFR reductions that is not expected to affect the TAF sites.
Otherwise, diurnal mixing will lead to continued cumulus during
the first few hours of the period in the 4.5 to 6kft agl range.
South to southwest winds will average 6 to 12KT with gusts to near
20KT. However, the winds should slacken and gusts subside toward
00Z and the cumulus should also dissipate. Light and variable
winds will prevail overnight, before becoming south to southwest
at 5 to 12KT with some gusts up to 20KT. By the end of the period
some cumulus may again develop between 4 and 6kft agl.

&&

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

&&

$$

SHORT TERM...JP
LONG TERM...JMW/MARCUS
AVIATION...JP