Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

258
FXUS63 KJKL 202147
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
547 PM EDT Mon Jul 20 2026

.KEY MESSAGES...

- A strong cold front could produce multiple rounds of thunderstorms
  on Tuesday into Tuesday night.

- There is a conditional threat for severe weather on Tuesday
  including damaging winds, large hail, and isolated tornadoes.

- Torrential rainfall from training thunderstorms could lead to
  flash flooding.

- Mainly dry weather is expected from Wednesday night to Friday
  with temperatures averaging about 5 degrees below normal.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 538 PM EDT MON JUL 20 2026

Seasonably hot conditions are in place over eastern Kentucky this
afternoon with temperatures in the mid to upper 80s. It is rather
muggy, however, as dew points range from 70 to 80F. Satellite
imagery shows a substantial cumulus field across the area, but
substantial dry air and capping around and just above 700 hPa is
keeping a lid on most of the towering cumulus for now. Analyzing
the surface fields, a warm front is draped from far northeastern
Kentucky extending back to the west and northwest to northern
Wisconsin, where it has been occluded by a trailing cold front
originating from an ~993 mb surface low north of Lake Superior.
From the triple point, the cold front extends southwest and
westward into Wyoming. A very moist air mass is in place to our
south and west, with a broad area of 2+ inch PWATs across much of
the mid and lower Mississippi Valley. Looking aloft, northwest
flow is present across the Ohio Valley region as an ~596 dam high
slowly rotates over the Central Rockies, and a mean trough with
embedded shortwaves is in place over eastern Canada and the Northeast
CONUS. A prominent shortwave is noted over Northwest Ontario,
supporting that strong surface low norht of Lake Superior. A 50
to 65 kt 500 hPa jet streak is situated south of the shortwave,
extending from the Northern Plains to the Upper Great Lakes. TD 2
is also spinning over the open Gulf waters south of the Florida
Panhandle and west of the Florida Peninsula but will have little
impact on our weather.

Through the short-term period, the aforementioned shortwave trough
and a subsequent one will carve deeply into the trough, effectively
shifting the mean trough axis westward to over the Eastern Great
Lakes by daybreak Wednesday. This will support the surface low
holding steady or strengthening slightly while tracking eastward
around the southern end of James Bay. For our region, this will
leave eastern Kentucky under slow height falls tonight in the open
warm sector amidst a mild and moistening southwest low-level return
flow. Meanwhile, the trailing cold front will drop southeast
through the Upper Midwest this evening and tonight, with the
associated 500 hPa jet sinking southeast as well. Shear parameters
will strengthen to levels supportive of organized convection.

Some of the CAM guidance as well as the RAP13 support convection
firing along and ahead of the front, growing upscale, and
consolidating into an MCS that dives into eastern Kentucky and/or
adjacent areas as it decays late morning to early afternoon on
Tuesday. Should this system materialize and maintain long enough
to reach our area, it would minimize destabilization in impacted
areas. Later day and evening convection should then fire along and
just ahead of the cold front, with the most intense convection
focusing within the high instability axis that develops in the
more pristine air mass further southwest. Of concern with this
kind of scenario would be the potential for training convection
developing along the southwest flank of the remnant MCS plus
additional training convection potential with the approaching cold
front.

PWATs around or exceeding 2.0 inches, coincident with NAEFS
moisture transport values reaching 4 standard anomalies above
climatology and deep warm cloud layer processes, will pose a risk
for extremely high rainfall rates despite rapid cell motions.
While individual cells will likely not cause substantial hydro
concern, any persistent training could quickly drop multiple
inches of rain. The potential for heavy rainfall from this
environment is noted by the extreme rainfall 6+ inch bullseyes
generated in various CAMs. At this point, confidence in the
evolution of any potential leading MCS and the downstream
mesoscale effects remains too low to highlight a spatial
footprint of greatest concern. In various operational and
experimental CAM solutions, the axis of highest rainfall extends
from roughly Cincinnati, OH to Charleston, WV in the most
northeasterly solution to along the I-65 corridor in the most
westerly scenarios. The heavy rain potential is captured to a
limited degree by the 20/12z HREF which shows at least a 10%
probability for 3 or more inches of rain occurring within a 3-hour
period (within 25 miles of a point) across all of eastern
Kentucky. This is in excess of the 3-hour FFG over practically
all of eastern Kentucky. In reality, those probabilities will
probably be higher in a more narrow but as of yet undetermined
corridor. It is also worth noting that there are also some CAM
solutions which do not even support an early day remnant MCS
reaching our area; in that case, the entire area destabilizes
strongly and the severe threat would likely dominate. Due to
large disparities in the data, confidence was not high enough to
issue a focused Flood Watch on this forecast cycle.

That brings us to the highly notable but also conditional severe
weather threat that will be present ahead of the cold front. The
shear due to the upper-level jet will be more than sufficient for
organized convection, with 30 to 40 kts of 0-6 km bulk shear;
however, the instability to fuel strong convection will be
conditional upon where (and if) a remnant pre-frontal MCS impacts
eastern Kentucky and limits destabilization. For areas not impacted
by significant midday convection, strong destabilization is
likely, with the 20/12z HREF showing an axis of 3,000+ J/kg of
mean SBCAPE extending southwest from Central Kentucky into the Mid
and Lower Mississippi Valley. From a probabilistic standpoint,
the 20/12Z HREF 2-5 km UH max bullseye extends from the
Bluegrass/Red River Gorge area southwestward across Central
Kentucky. Typically, most severe weather occurs under this
bullseye and further into the zone of high instability. In this
12Z scenario, this would tend to favor the most widespread severe
weather occurring along and west of the Pottsville Escarpment;
however, given the model spread, this is still prone to change. In
terms of hazards, both discrete supercellular and strong linear
storm segment modes appear to be favored. The severe weather
parameter space is most favorable for damaging winds, with the 12Z
HREF supporting at least a 10 percent chance of sustained winds
exceeding 50 kts within 25 miles of a point over Central Kentucky
west of the Pottsville Escarpment. Sufficient directional shear
in the low-level hodograph supports 100 to 200 m2/s2 of SRH,
which is within the favorable range for tornadogenesis. Large hail
could also be a threat with stronger supercells, but hodographs
aren`t all that straight/long and freezing heights are very high;
thus even any intense storms should struggle to produce hail of
significant size.

Boiling all of that down into sensible terms, isolated showers
and thunderstorms will largely diminish this evening, though a few
rogue showers or rumbles of thunder could still linger or pop up
overnight. It will be very mild with lows ranging in the lower to
mid 70s. Some fog is possible, primarily in the more sheltered
mainstem river valleys over southeastern Kentucky. For Tuesday,
showers and thunderstorms are likely to impact the area at times
from late morning through the evening. Some of the storms could be
severe, with damaging winds as the primary threat, and large hail
and tornadoes as secondary threats. If storms train over a given
area, torrential rainfall could lead to flash flooding, and under
worst-case scenarios, that flooding could become a significant
threat to life and property. It will be very humid and warm with
high temperatures mainly in the 80s. It will also be breezy with
southwesterly winds gusting up to 20 and 25 mph at times. Showers
and any lingering storms slowly diminish from the northwest
Tuesday night while temperatures settle back into the 60s for most
locations on a northwest breeze.

.LONG TERM...(Wednesday through Monday)
Issued at 547 PM EDT MON JUL 20 2026

The models are in good agreement with an amplified and stagnant
long wave pattern to rule over the CONUS through early next week.
The center of a seasonably strong upper level ridge will meander
from the southern Plains to the Four Corners region, while broader
troughing modulates east of the Mississippi River. This will result
in a reprieve from the humidity across the Ohio and Tennessee
valleys through the middle of the week. Humidity will be on the
increase once again across the region by this weekend and into early
next week.

On Wednesday, a surface cold front will be exiting into Tennessee,
with enough low level moisture lingering to allow for some renewed
convection, especially across far southeastern Kentucky. High
pressure builds in more decisively Wednesday night, with welcomed
northeasterly low level winds ushering in much lower dew points than
we have seen lately. Some fog will likely occur following the
multiple rounds of showers and thunderstorms seen across the area,
although the pressure gradient may limit this coverage. Drier and
cooler weather will be in full swing on Thursday.

As troughing sharpens back up over the Ohio Valley, bouts of
short wave energy will be moving southeast within the established
northwesterly flow aloft. Model details regarding timing are lower
confidence this far out, but rain chances will return as some
moderate moisture advection occurs in the low levels, with LREF
mean PWATs of 1.4 to 1.5 inches nosing back into southeastern
portions of the Commonwealth by Friday. PoPs look to peak Friday
night into Saturday, with somewhat better model agreement on
increased mid and upper level forcing in place. For the rest of
the weekend and early next week, despite the favorable stormier
track that northwest flow can mean aloft, mean PWATS right now
remain in the 50th to 75th percentile, so only slight to chance
PoPs are in the forecast for Sunday through Monday.

Highs will retreat to the upper 70s to lower 80s Wednesday and
Thursday, before gradually warming to the mid to upper 80s by
Monday. Overnight lows will moderate from the upper 50s and low 60s
mid-week, to the upper 60s and around 70 by early next week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 217 PM EDT MON JUL 20 2026

At issuance time, a scattered cumulus field was found over the
eastern Kentucky. Expect cloud bases generally in the 3.0 to
4.0kft AGL for a majority of the afternoon and evening. A few
isolated showers or even a weak thunderstorm cannot be ruled out
but confidence was too low to mention at the terminals. Patchy
cloud cover both at the mid-levels and aloft will persist through
tonight and any valley fog should remain more confined to the
deeper southeastern river valleys. A more widespread threat for
shower and storms, some of which could be severe, will arrive
around and just beyond the end of the TAF period as a strong cold
front approaches. Winds will remain light and variable through
tonight.

&&

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

&&

$$

SHORT TERM...GEERTSON
LONG TERM...JKL
AVIATION...GEERTSON