Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

289
FXUS63 KJKL 240241
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1041 PM EDT Thu Apr 23 2026

.KEY MESSAGES...

- Warm and dry weather is expected into the day Friday.

- Showers are likely from Friday evening/night into Saturday, with
  a few general thunderstorms possible.

- A stronger system brings another chance for widespread showers
  and storms late Monday into Tuesday, but severe weather
  potential is uncertain in Eastern Kentucky.

&&

.UPDATE...
Issued at 1040 PM EDT THU APR 23 2026

The late evening update refreshes hourly T/Td grids, with not much
change needed otherwise.

UPDATE Issued at 626 PM EDT THU APR 23 2026

Late afternoon/early evening update is out with no major changes
besides very minor updates to Sky and hourly T/Td grids.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 415 PM EDT THU APR 23 2026

Late this afternoon, an area of upper ridging extended from the
Carolinas to the Central Great Lakes. Meanwhile, an upper level
low was centered near the Alberta and Saskatchewan border with an
upper trough extending into the Plains. At the surface, a frontal
zone extended from the mid Atlantic states/Delmarva into the
Great Lakes to a sfc low in Alberta. A cold front trailed from
this system into the Central to Southern Plains while sfc high
pressure was centered off the southeast US Coast and extended
into the Southeast to Southern Appalachians. Deep mixing has
occurred today and has led to rather high based cumulus across
eastern KY between 6.5 and 8kft agl. In this mixing dewpoints
have mixed well into the 40s despite westerly flow level flow.

Sfc and upper ridging will generally remain dominant tonight as
the upper low meanders over the Saskatchewan vicinity through
Friday night. An associated shortwave will progress east across
the Central Conus tonight and reach the mid and upper MS Valley
to western Great Lakes late tonight into Friday morning. This
shortwave should progress east into the western to central Great
Lakes to Lower OH Valley by late Friday afternoon and evening and
then toward the eastern Great Lakes to middle OH Valley Friday
night. This shortwave should result in height falls later on
Friday through Friday evening as moisture increases through the
column. An additional shortwave is progged to approach to end the
period. Meanwhile, the preceding sfc low is progged to move to
southeast to the eastern Great Lakes by the end of the period
with the southern end of the boundary sagging into eastern KY to
end the period.

This evening and tonight, the cumulus should gradually diminish
around or shortly after sunset and with high pressure once again
dominating a moderate magnitude ridge valley split with deeper
eastern valleys dropping to the mid 40s and coalfield ridges only
settling into the upper 50s. Diurnally driven cumulus should
develop on Friday and as moisture increases isolated to scattered
showers and a storm or two are anticipated Friday afternoon. The
shortwave and front approach Friday night and at least scattered
rain showers are expected. This activity will be coming through
the area during a min in the diurnal cycle and have limited
forcing. There may end up being a late evening to start of the
overnight round with the first shortwave and possibly a resurgence
of shower activity in the central or southeastern part of the
area ahead of the front late as the second shortwave nears. QPF
should be quite variable and has trended lighter in the high
resolution models.

.LONG TERM...(Saturday through Thursday)
Issued at 546 PM EDT Thu Apr 23 2026

Confidence remains high that Eastern Kentucky will see multiple
chances for measurable precipitation during the long term forecast
period. A pattern shift is coming, with multiple shortwave
disturbances gradually eroding the dominant ridging over the SE
CONUS. The first of these disturbances will move through the Ohio
River Valley on Saturday, after producing some upstream convection
on Friday night. As that activity enters the temporal range of
higher-resolution models, the forecast guidance suite is suggesting
that it may be in a weakening state, perhaps with lesser rain
coverage on Saturday morning than in previous forecasts` thinking.
Guidance has collectively trended the parent shortwave ejection and
related surface frontal passage later in the day on Saturday, and
this yields an interesting forecast for Saturday afternoon and
evening. If activity is rather meek/disorganized when the period
opens on Saturday morning, the arrival of the lagged forcing could
spark additional convection on Saturday afternoon/evening. The
greatest chances for this currently look to be in eastern and
southern portions of the CWA, but the intensity of this activity is
contingent on the conditions realized on Saturday morning. There
should be sufficient instability for a few thunderstorms (pre-
frontal highs are in the 70s, pre-frontal dews are in the low 60s,
and mean LREF values are around 500 J/kg), but bulk shear looks
rather weak (less than 25 knots). Any stronger storms on Saturday
would need higher-than-expected instability due to lower-than-
expected cloud cover earlier in the day, and they would likely need
to take advantage of a leftover mesoscale-type boundary to organize.
Convective trends will be monitored closely, but this first event
continues to look more beneficial than it does impactful.

While the aforementioned weakening trend with Friday night`s
activity has caused the first wave`s QPF numbers to tick downwards,
a wetting rain (>0.10 inches) is still likely. Given that the entire
JKL CWA was placed in either D1 (Moderate Drought) or D2 (Severe
Drought) in today`s US Drought Monitor update, any rain will prove
highly beneficial. A north-south range of 0.2-0.4 inches of rain is
currently included in the forecast grids from Friday afternoon
through Saturday evening, with locally higher amounts possible
wherever any additional thunderstorms track in Southern KY. 12z LREF
probabilities for at least 0.1 inches of rain from this first round
remain in the 85-95% range area-wide, but if the accumulation
threshold is raised to 0.25 inches, greater than 60% probabilities
become confined to the south of the I-64 corridor. Expect rain
chances and sky cover to taper off from NW to SE once the cold front
passes through on Saturday evening.

A pronounced shift to north-northwesterly surface winds will advect
a cooler and drier airmass into the region for Saturday night, and
the building of a shortwave ridge aloft supports the idea that
Saturday night could feature efficient diurnal processes. If
sufficient clearing is realized, ridge-valley temperature splits and
river valley fog could come to fruition. Forecast uncertainty
precludes the mention of anything beyond patchy fog in this forecast
package`s grids, but the combination of wet grounds and a drier
upstream airmass results in perhaps the most favorable fog forecast
so far this season. Under the influence of that ridging, Sunday
continues to look like a warmer and drier day, with partly cloudy
skies and highs in the upper 70s/near 80. However, the ridge quickly
propagates east throughout the day, and the previous day`s boundary
begins to move north as a warm front as upstream cyclogenesis occurs
on Sunday night. The resultant return flow aloft could lead to warm-
air advection type showers in southern portions of the forecast area
on Sunday evening/night, and this will set the stage for a second,
more robust system to approach the forecast area early next week.

Models continue to depict more robust upper- and mid-atmospheric
support for Monday and Tuesday`s storm system. A second, sharper and
negatively-tilted trough ejects into the Ohio River Valley at some
point in this time frame, with this morning`s guidance cycle
trending a little bit later. The previously-mentioned surface
cyclogenesis out ahead of this feature will pull the warm frontal
boundary closer to the Ohio River on Monday morning. This places the
forecast area firmly within the warm sector of this system, with
vertically stacked southerly to southwesterly flow throughout the
column. Open warm sector convection cannot be ruled out during peak
diurnal heating on Monday, but the best frontal forcing and
kinematic lift will lag out to the west, closer to Paducah. As the
parent features shift northeast into the Great Lakes overnight, a
pronounced 45-55 knot 850mb jet will pump a plume of instability out
ahead of the front. We will need to monitor the potential for
upstream convection to congeal into a QLCS, but the trend towards
later arrival in Eastern Kentucky means that those storms may arrive
at the diurnal instability minima. Thus, the highest severe
potential on Monday will likely be relegated to the west of the I-65
corridor, but lower-tier SPC outlooks may be introduced to our
portions of the state as the event approaches. If this second
system`s cold front continues to trend later, the severe risk in
Eastern Kentucky could continue into Tuesday. Some of today`s
deterministic model guidance suggests that sufficient destabilization
could occur on Tuesday afternoon after Monday night`s activity
pushes eat, and the shear with this second system is poised to be
much higher than it was with the first. As such, this system still
bears watching, and interests are encouraged to stay tuned to future
forecast updates. Forecast confidence will continue to improve as
the evolution of the first system is solidified and as the second
system enters the temporal range of high-res guidance. In summary,
and as per usual, the severe weather potential in Eastern KY with
both systems is highly contingent upon the evolution of upstream
activity.

Regardless of severe storm potential, an additional wetting rainfall
is likely early next week. The highest rain chances (still in the 80-
90% range) currently fall immediately ahead of the frontal passage
on Monday night into Tuesday morning, with lower, but still
mentionable chances on Monday and Tuesday afternoons. Today`s LREF
probabilities for >= 0.25 inches of rain with this system are
between 60-80%, with the highest values in western locales. If this
threshold is increased to 0.50 inches, those probabilities decrease
to the 30-50% range, but this particular ensemble does not take into
account convective-allowing models at the current temporal range.
Locally higher precipitation totals are plausible wherever
thunderstorms track, and especially wherever multiple rounds of
activity occur. The forecast grids continue to depict a widespread
0.75 to 1.25 inches of rain between Monday morning and Tuesday
evening, but there will likely be greater spatial variability in the
system totals than what is currently in there.

Deterministic model spread begins to increase towards the middle of
next week, but there are hints at a cooler and wetter pattern to
wrap up April and begin the month of May. Altogether, this should
help mitigate the ongoing drought and fire weather concerns in
Kentucky.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 721 PM EDT THU APR 23 2026

VFR conditions are expected to prevail through the TAF period,
though after 21z Friday PROB30 groups have been added at KSYM,
KIOB, and KSME for low chances of showers and/or thunderstorms,
with MVFR or lower conditions possible if those were to verify.

West-southwest to southwest winds will decouple or diminish to
less than 5 kts this evening through the overnight, with winds
increasing again to the 6 to 12 kt sustained range by 16z Friday,
with a few gusts reaching to 20 kts in the afternoon during the
peak mixing period.

&&

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

&&

$$

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