Severe Weather Potential Update

974
FXUS63 KJKL 201055
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
655 AM EDT Wed May 20 2026

.KEY MESSAGES...

- Shower and thunderstorms will become more prevalent today, with
widespread rain chances continuing through the next seven days,
including the holiday weekend.

- The switch to an active and wetter pattern yields temperatures
closer to normal readings, and is likely to provide at least
temporary relief from drought conditions.

&&

.UPDATE...
Issued at 622 AM EDT WED MAY 20 2026

Showers and thunderstorms have developed in the last hour or so along
a moisture (i.e., theta-e) gradient roughly parallel to the
western escarpment of the Cumberland Plateau. This activity is
ahead of the cold front, which is still west and northwest of the
forecast area across central Kentucky. PoPs and Sky grids have
been updated to reflect these trends. Hourly T/Tds have also been
updated in the very near term.

&&

.SHORT TERM...(Today through Thursday)
Issued at 328 AM EDT WED MAY 20 2026

A cold front will move southeast into eastern Kentucky this
afternoon, then come to a stall later tonight through Thursday
along the TN and VA borders. Meanwhile, broad forcing for ascent
increases across the area through the day as a slow-moving
shortwave approaches from the southwest, with the shortwave
becoming gradually sheared out across southeastern Kentucky
tonight into Thursday as shortwave ridging builds over the area by
Thursday evening.

As the front approaches from the northwest today and the
aforementioned shortwave approaches from the southwest, rain
chances will steadily increase. Current dew points in the 60s
combined with a developing mid-level 30-40 kt speed max ahead of
the shortwave will provide the kinematics and thermodynamics for
scattered thunderstorms this afternoon, with low to moderate
buoyancy from surface high temperatures forecast to reach the
lower to mid 80s for much of the area, warmest in the Big Sandy
Basin. Thus, a few isolated severe storms will be possible, with
damaging winds and hail the primary severe threats. Additionally,
downpours may cause localized high water issues in poor drainage
areas.

Showers and thunderstorm activity transitions to more of a
shower/rain threat tonight into Thursday as the shortwave becomes
sheared and the cold front stalls near or along the TN and VA
state lines, creating more of an overrunning situation. The
building upper ridging Thursday may allow for northwestern parts
of the forecast area, especially toward the I-64 corridor and
Bluegrass region, to stay mostly if not completely dry, as shower
activity becomes more confined with time closer to the stalled
front across southeastern Kentucky.

Temperatures tonight will likely cool into the 50s, especially for
northern areas behind the cold front, while lower to mid 60s for
lows are expected toward the TN border to the south of the
stalling front. Thursday`s highs will be below normal for northern
and central parts of the forecast area, likely around 70 degrees
under persistent cloud cover and shower chances, with highs
closer to normal near and south of the front near the TN and VA
borders.

.LONG TERM...(Thursday night through Tuesday)
Issued at 302 AM EDT WED MAY 20 2026

The forecast period begins with the region likely situated north of
a frontal zone Thursday night as a shortwave in southwest flow
approaches the region. This should support the boundary lifting
north as a warm front as a sfc wave rides into the OH Valley. With
the northwest lifting warm front, it is probable that chances of
convection will spread north through the overnight period Thursday
night. Overnight lows are still expected to be mild as the warm
front lifts north across the area.

This warm front will cross the region on Friday, serving as the
catalyst for widespread showers and scattered thunderstorms
throughout the day as another wave moves along the boundary and
treks toward the Great Lakes for Friday night. While marginal
thermodynamic indices will once again favor pulse-type, non-severe
convection, the primary hazard shifts toward heavy rainfall and high
precipitation efficiency. This boundary likely remains north of the
area to start the weekend, before sagging back into the OH Valley
and stalling to end the period. Passing disturbances and the
moist airmass, with PWs per the 12Z LREF generally in the 1.3 to
1.7 inch range, or the 90th percentile, should at least be
conducive for a diurnal uptick in convection for Friday to Monday.
The 12Z Tuesday LREF event totals through 8 PM EDT on Monday have
a min to max range of 0.75 inches to near 7 inches, while the
25th to 75th percentile range from 1.5 or 1.75 inches near the VA
border to 3.75 inches in the north and west.

Recent deterministic guidance projects widespread QPF amounts ranging
from 2.00 inches in the Lake Cumberland area to 2.75 inches across
northeastern portions of the forecast area, with lesser amounts
near 1.5 inches in southeastern KY near the West Virginia and
Virginia borders, due to local downsloping effects. As a side
note, since the area is dry, heavy rainfall on top of moisture
starved ground could create runoff issues leading to potential
hydrologic issues.

Ultimately, this period will highlight a distinct regime shift
toward a much wetter synoptic setup, a stark difference from the
persistent dry pattern observed over the last few weeks and
months. Due to persistent cloud cover and rain, daytime highs
will remain capped in the upper 70s to mid 80s, while overnight
lows drop into the lower to middle 60s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 655 AM EDT WED MAY 20 2026

Showers and thunderstorms have developed along a moisture gradient
between KIOB/KSYM and KJKL/KSME this morning, and this activity
will move northeast and primarily impact KSYM and possibly KIOB
this morning with sub-VFR conditions. Otherwise, showers and
thunderstorms will re-develop between midday and mid-afternoon
across the area, with an active mid-afternoon through early
evening period before activity diminishes to showers and pockets
of steadier rain, though an isolated thunderstorm cannot be
totally ruled out through the late evening.

As the cold front stalls out across the area after 00z, expect
more widespread MVFR or lower conditions with low cigs and
possibly viz to develop at most if not all sites, continuing
through the end of the TAF period.

&&

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

&&

$$

UPDATE...CMC
SHORT TERM...CMC
LONG TERM...JP/VORST/CMC
AVIATION...CMC