Somerset, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

067
FXUS63 KJKL 201004
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
604 AM EDT Mon Jul 20 2026

.KEY MESSAGES...

- A significant cold front could produce multiple rounds of
  thunderstorms on Tuesday and Tuesday night. Those storms will be
  capable of severe weather and excessive rainfall.

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

&&

.SHORT TERM...(Today through Tuesday)
Issued at 535 AM EDT MON JUL 20 2026

Early this morning, an upper level ridge was centered in portions
of the Rockies in the CO vicinity while an upper trough extended
from eastern Canada into the Northeast Conus to Mid Atlantic.
Another upper ridge was centered in the Atlantic between Bermuda
and the Bahamas while TD 2 was over northeast portions of the
Gulf. At present northwest flow aloft extended from the upper MS
Valley across the Great Lakes and OH Valley into the Mid Atlantic
States, downstream of an upper level low in Manitoba and an
associated shortwave that extended into the Dakotas. At the
surface, a stalled out frontal zone was in place from near the VA
and NC border into northeast TN and southeastern KY near the TN
border and then further west and then north across the mid MS to
the upper MS Valley to a low pressure system centered near the
Manitoba and Ontario border area. North of the boundary a ridge
of sfc high pressure extended from the mid Atlantic states to the
southern portions of the Great Lakes. North of the boundary,
dewpoints in the northern half to two thirds of the CWA have
dropped off into the 60s with generally low 70s south. The
moisture gradient is also evident in PW analysis with values near
1 inch in northeastern KY and 1.5 to 1.6 near the TN border. In
the south, nearer to the stalled/stalling frontal zone, a mixture
of stratus and stratus build down of fog was in place while
further north clouds were less sparse and valley fog was present.
Some of the fog was dense in spots.

Today and tonight, the upper level ridge should remain centered
in sections of the Rockies/CO vicinity and build toward the
interior northwest and into portions of the central to southern
Plains. Downstream, a upper trough should remain in place from
eastern Canada into the eastern Conus, however the upper
low/shortwave in Canada should dig the trough into the western
Great Lakes to Lower OH Valley region by the end of the period.
Additional weak shortwaves/possible MCV from upstream convection
could also reach the OH Valley near or before dawn on Tuesday. The
associated sfc low will track across Ontario to a position to the
south or southwest of James Bay by late tonight. The frontal zone
currently stalled/stalling over eastern KY should lift north and
northeast as a warm front today and move north and northeast of
eastern KY tonight with the area getting well into the warm
sector. Meanwhile, the cold front from the sfc low in Canada
should sweep across the western and into the central Great Lakes
tonight and south across sections of the Northern Plains and upper
MS Valley and into the mid MS Valley and Central Plains. The
upper low should meander over sections of Ontario to the north of
the Great Lakes through Tuesday with the trailing 500 mb
shortwave/shortwaves rotating across the Great Lakes into the OH
Valley. An initial shortwave and potential MCV convective
remnants from upstream of the area could track across parts of the
OH Valley on Tuesday while the cold front will continue sweeping
east and southeast into the eastern Great Lakes to Lower OH Valley
region. Well south of the area, TD 2 should meander over northern
portions of the Gulf or the Gulf coast and little affect on
sensible weather for eastern KY.

For today, the initial low clouds and fog should gradually lift
an dissipate this morning for the more southern locations. With
daytime heating and the boundary of the vicinity if not lifting
north when combined with little change in 500 mb heights could
support isolated to perhaps scattered showers and thunderstorms
today. MLCAPE per the 06Z RAP gets into the 750 J/kg range from
northeast to near 2250 near the KY and TN border but shear remains
quite weak. Convective allowing models generally have development
nearer to the VA and TN borders and near and north of I-64. This
activity should be relatively disorganized, but a heaver downpour
is not completely out of the question. A few showers or storms
cannot be ruled out in the warm sector today, but more substantial
activity is anticipated on Tuesday.

On Tuesday in the warm sector, MUCAPE should reach 2000 to 3000
J/kg with MLCAPE of 1500 to 2250 J/kg. Effective shear should
reach roughly the 30 to 45KT range. There should be some
directional shear by late afternoon/evening in the low levels and
0-1, 0-3, and effective SRH could climb to near or in excess of
200 m2/s2. Storm mode remains a question of more discrete cells or
a mix of discrete cells and line segments with any remnant
activity during the morning to mid afternoon timeframe. The 06Z
HRRR points toward the potential for some discrete cells (multiple
2-5km UH swaths over central KY extending into parts of eastern
KY during the later part of the afternoon into the evening, before
a consolidation to more linear convection as the cold front
nears. Overall, for Tuesday and into the start of the long term
period on Tuesday evening, the primary threat appears to be
straight line wind gusts in the 45 to 70 mph range producing
damage. An rotating cells could produce some hail despite the warm
environment up to around quarter-sized as well as the potential
for isolated tornadoes. Any linear convection may be QLCS in
nature with damaging wind the primary hazard, but any interaction
with boundary or optimal alignment with 0-3KM shear could produce
a brief spin up tornado or two.

In addition to the severe threat, PW should be elevated in the
warm sector getting into the 90th to 99th percentile range or 1.8
to 2.1 inches per Some locations could experience multiple rounds
of storms. The 06Z HRRR run, although just one model run,
illustrates the potential for heavier rainfall amounts in a 6 hour
period or less with some 3 to 5 inch amounts in a couple of spots
near the I 75 corridor in central to south central KY. Upper end
6 hour rainfall per the 00Z HREF are also in this range.

The Tuesday Severe and Excessive Rainfall Hazards continue to be
highlighted in the HWO as well as Social Media and DSS Packet
posts. SPC has locations generally near and north of the Mountain
Parkway in a Day 2 Enhanced Risk (Level 3 of 5) for Severe Storms
with a Slight Risk (Level 2 of 5) for the remainder of the area.
Meanwhile, WPC has placed all of eastern KY in a Slight Risk for
Excessive Rainfall on Day 2 as well for the hydro concerns noted
above.

.LONG TERM...(Tuesday night through Sunday)
Issued at 445 AM EDT MON JUL 20 2026

At the start of the long term period, the area sits ahead of a
potent cold front. This front is initially expected to extend
across the eastern Great Lakes to Lower OH Valley from a sfc low
in Canad to the south and southeast of James Bay. Also at that
point, a shortwave trough is expected to be rotating through the
Great Lakes to OH and TN Valleys.

A model sounding from the 00Z suite of data shows conditions at
01Z Wednesday (9 PM Tuesday) as follows: MLCAPE around 2000 J/kg,
Effective Bulk shear of 35-40 kts, 0-1 km SRH around 170 m2/s2
and 0-3 km SRH near 290 m2/s2, and DCAPE near 1300-1400 J/kg.
Different models also suggest that PWAT could remain between 1.75
and 2.00 inches ahead of the cold frontal passage during the late
evening and into the night. The above parameters highlight an
environment favorable for organized cells to sustain updrafts
given models sounding hodographs showing a critical angle of 92
degrees (near textbook orthogonal flow). With DCAPE of 1300 J/kg,
wet microbursts are also favored, where severe downburst winds of
60-70 mph gusts or more could be possible. While low-level
kinematics could still support discrete or semi-discrete storms
near sunset, the high DCAPE and potential strong cold pool
development and forcing from the front suggest storms will likely
consolidate quite rapidly into a bowing QLCS/MCS by around or
shortly after sunset. In summary, the greatest weather threat
appears to be strong to severe damaging wind gusts, though
isolated tornadoes and large hail around quarter-size cannot be
ruled out. As such, the SPC has put the area in a Day 2 Enhances
Risk (Level 3 of 5) for Severe Weather, covering an area near and
north of the Mountain Parkway with a Slight Risk (Level 2 of 5)
for Severe Weather elsewhere.

To add to a busy Tuesday evening mean PWATS of 1.75 to 2.00 inches
across the area fall within the 97th to 99th percentile against
climatology. Integrated water vapor transport will also approach the
99th percentile of climatology during this timeframe. With days of
repetitive rainfall having already primed soils, any storms late
in the evening into the overnight could produce additional periods
of heavy or torrential rainfall which could lead to isolated to
scattered instances of flash flooding. As such, the WPC has all of
the forecast area in a Slight Risk (Level 2 of 4) for Excessive
Rainfall meaning isolated to scattered instances of flash flooding
will remain possible into the evening.

The cold front is expected to be south of the forecast area by
Wednesday morning, though isolated to scattered showers and storms
will linger through the morning, with chances tapering by evening,
as high pressure builds into the area. Quiet conditions are
expected across Eastern Kentucky from Wednesday night through the
better half of Friday. However, models and ensembles depict the
next system ejecting out of the Central Plains later Friday and
Friday night into the Tennessee Valley and then gradually across
portions of the Southern Appalachians/Southeast. This scenario
leads to renewed shower and storms chances Friday evening,
through Sunday. At present, chances look to remain isolated to
scattered in nature (15-35% chance), with the best chances further
south nearer to the VA and TN borders.

Temperatures will generally be 5 degrees below normal to start
the extended, ranging from the upper 70s to low 80s Wednesday and
Thursday following the cold frontal passage Tuesday night.
Temperatures then generally warm to the mid to upper 80s for highs
this weekend. Overnight lows will range from the upper 60s to
around 70 for Tuesday night, settled into the upper 50s to lower
60s Wednesday and Thursday nights, and trend milder into the mid
to upper 60s for most locations each night Friday though Sunday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 235 AM EDT MON JUL 20 2026

At issuance time, a mixture of low clouds/stratus as well as fog
was over the south near a stalled boundary while further north
valley fog had formed and there also a few passing low and mid
clouds there as well. In some areas the fog and or stratus was
resulting in IFR or lower reductions. Further fog and or stratus
development during the first 6 hours of the period is the main
aviation concern. South of a KJKL to KSJS line, recent trends and
guidance support reductions to near or below airport mins for a
few hours through 14Z with KSME and KLOZ expected to be affected.
KSJS and KJKL should eventually have MVFR to IFR reductions as
fog lifts into those areas. At this point, VFR is expected to
remain throughout the entire period for KSYM and KIOB. Fog and any
low clouds should dissipate between 12Z and 15Z, giving way to
prevailing VFR conditions through the remainder of the period.
With the boundary lingering over the area isolated to scattered
showers and storms may affect locations generally south of a KSME
to KLOZ to KJKL to KLOZ line after 16Z. Winds will be light and
variable outside of any storms.

&&

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

&&

$$

SHORT TERM...JP
LONG TERM...JKL
AVIATION...JP