Jenson, Kentucky Weather Forecast Discussion

270
FXUS63 KJKL 220033 AAA
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
833 PM EDT Sun Sep 21 2025
.KEY MESSAGES...
- A few thunderstorms could become strong to severe on Monday
  afternoon and evening, with the main threat being isolated
  damaging wind gusts.
- Widespread, generally beneficial rainfall is expected this
  week, which will help to improve ongoing drought conditions.
- Excessive rainfall and concerns for isolated instances of high
  water or flash flooding may become a threat by midweek.
- An additional threat for strong thunderstorms may develop on
  Thursday, but there is still high uncertainty in the forecast
  for late this week.
&&
.UPDATE...
Issued at 833 PM EDT SUN SEP 21 2025
Much of the convection has diminished across the region over the
past couple of hours. A bit of instability lingers in the west
where coverage was generally less during the afternoon. In
general, convection should wane by late evening, though cannot be
completely ruled out, especially late tonight in the north.
Otherwise, clouds should scatter out overnight and give way to
some valley fog particularly in the southeast. Other than the
addition of valley fog to the grids overnight, hourly grids were
also trended based on recent observations.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 309 PM EDT SUN SEP 21 2025
A split-flow pattern continues with the southern stream becoming
more active across the center of the country. A quasi-stationary
longwave trough remains trapped to the south of a blocking high over
central Canada. Disturbances continue to move through the west-
southwesterly flow across the Ohio Valley, resulting in an unsettled
weather pattern for the short-term.
A Marginal Risk for severe storms remains in effect given CAPE
values approaching 2000 J/kg along with a band of mid-latitude
westerlies producing effective shear values in the 20 to 25 kts
range. This is supportive of pulsy convection capable of producing
gusty winds and half-inch hail, with an isolated instance of
damaging winds possible if a storm were to become organized.
Warm advection remains into tonight, but models indicate increasing
stability despite stronger shear moving over the area. Would thus
expect shower and thunderstorm chances to continue, but not as
strong or widespread as this afternoon into early this evening.
A better threat for a few stronger storms arrives Monday as a
stronger upper tropospheric disturbance and the core of stronger mid-
level winds move across the area coincident with peak diurnal
heating in the mid- to late afternoon period. The SPC has thus
continued a Marginal Risk for severe storms for all of eastern
Kentucky for Monday. The upper tropospheric disturbance does not
exit the area until late Monday night, keeping showers and
thunderstorm chances in the forecast.
.LONG TERM...(Tuesday through Sunday)
Issued at 309 PM EDT SUN SEP 21 2025
A stronger upper disturbance rounds the base of the longwave trough
Monday into Tuesday which becomes stretched from southeastern Canada
southwest to the center of the country, with an upper low becoming
established over the center of the country. Additionally, a
seasonally strong westerly jet stream becomes established Tuesday
from the Four Corners region east to the Mid-Mississippi Valley.
This jet then becomes increasingly more southerly with time
through Friday morning as a high-amplitude trough becomes
established from the Great Lakes to the northern Gulf of America.
By next Saturday, the GFS and ECMWF begin to diverge as to whether
this trough closes off into an upper low over eastern Kentucky,
or whether the associated trough becomes embedded within a highly
amplified upper trough over the eastern U.S.
A very active weather pattern is expected Tuesday through Friday,
with the potential for excessive rainfall each day (Marginal Risks
Monday and Tuesday, Slight Risks Wednesday and Thursday), as well as
one or more severe weather threats later Wednesday through Thursday,
with the highest uncertainty involving how much instability is
available within a strong warm advection pattern with strong mid-
level winds. Interests in the eastern Kentucky region should remain
weather aware and keep monitoring forecasts as this pattern evolves.
High temperatures will continue to trend downward each day as
unsettled weather continues through the period, with low
temperatures remaining elevated through at least Thursday night.
There will be the potential for cooler low temperatures Friday night
and beyond with the potential for cold advection depending on the
evolution of the mid-level pattern.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 815 PM EDT SUN SEP 21 2025
Most of the convection across eastern Ky has dissipated or moved
to the east of the area over the past couple of hours. However, A
bit of instability lingers in the west and southwest for a couple
of showers were occurring near KIOB and a few showers and storms
were occurring south of KSME to near KEKQ. Those showers and
storms could near KSME and KLOZ during the first couple of hours
and a PROB30 group was used. Generally, convection should wane
overnight. Also overnight, clouds should tend to scatter out and
valley fog is anticipated for non TAF sites locations between 04Z
and 13Z with reductions to MVFR and IFR. Otherwise, additional
showers and storms are anticipated during the second half of the
TAF period, generally after 15Z to 19Z. Reductions to MVFR or
lower are anticipated within any stronger convection later in the
periods and winds could gusts to 30KT or stronger. Winds outside
of showers and storms will be light and variable or southeast to
south at less than 10KT through 14Z, before becoming more
southwesterly at generally less than 10KT to end the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...JP
SHORT TERM...CMC
LONG TERM...CMC
AVIATION...JP

NWS JKL Office Area Forecast Discussion