JKL issues Area Forecast Discussion (AFD) at Sep 22, 5:08 AM EDT998
FXUS63 KJKL 220908
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
508 AM EDT Mon Sep 22 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.
&&
.SHORT TERM...(Today through Tuesday)
Issued at 420 AM EDT MON SEP 22 2025
Satellite imagery shows variable cloud cover across eastern
Kentucky at 8z this morning along with some fog in the more
sheltered river valleys. A few showers are present on radar west
of I-75 and north of the Mountain Parkway, but most locations are
dry. Temperatures range mainly in the 60s. The latest analysis
shows surface high pressure ridging extending from the Canadian
Maritimes southwestward along the Atlantic Seaboard. Meanwhile,
low pressure is taking shape in the lee of the Northern Rockies,
with a wavy frontal boundary extending eastward into the Great
Lakes. In between the high and low, the pressure pattern
(including over eastern Kentucky) consists of a weak pressure
gradient infused with various subtle shortwave and mesoscale
perturbations. Scanning aloft, 500 hPa ridging is departing off
the Atlantic Coast ahead of a low-amplitude 500 hPa trough
extending from Western Ontario southward along the Mississippi
River Valley. Further upstream, a Pacific trough is crossing the
northern Rockies.
The trough immediately to our west will gradually dampen and
slowly shift eastward through the short term, but not before
ejecting multiple pieces of vorticity energy across the
Commonwealth, most notably later today and tonight. As that trough
pulls away on Tuesday, the Pacific trough will dig deeply over
the Plains in the early stages of forming a closed low and will
begin impacting eastern Kentucky just beyond the end of the short
term. In the meantime, the first of multiple disturbances
associated with the Mississippi Valley trough will cross eastern
Kentucky today. Partial sun is expected to lead to moderate
destabilization (MUCAPE 1,000-2500 J/kg) by this afternoon while
modest shear of 20 to 30 kts will be sufficient for line segment
organization. The stronger forcing will pass over the northwestern
half of the forecast area, favoring locations near Lake
Cumberland and north of the Hal Rogers Parkway/KY-80 corridor for
the greatest chance of organized severe weather. Strong to
damaging winds would be the primary threat. Another disturbance
moves through tonight, focusing much of the activity again over
the northwestern half of the area. However, the threat of severe
weather is minimal with the activity overnight. Additionally,
PWATs surging to between 1.5 and 1.8 inches with a deep warm cloud
layer will be supportive of heavy downpours. For now, this rain
should largely be beneficial as the heaviest activity is likely to
occur in those areas most affected by ongoing abnormally dry to
moderate drought conditions. Locations favored to experience the
strongest storms this afternoon and evening could receive 1 to 2.5
inches of rain, with locally higher amounts possible. Lesser
totals are expected closer to the Virginia and Tennessee borders.
Convection will likely continue on Tuesday as the first trough
pulls away, but overall coverage and intensity should be less than
today and tonight.
In terms of sensible weather, a transition to wet and unsettled
conditions is expected for the new work week. A few showers this
morning will yield to more widespread shower and thunderstorm
activity this afternoon and evening (50% chance of precipitation
along the Virginia border up to 90% north of I-64). Some
thunderstorms could be strong, with gusty winds and torrential
downpours, especially north of a line from Pikeville to London. It
will be slightly cooler than yesterday, with high temperatures
mostly in the low to mid-80s under variable cloud cover. Tonight
will remain mild, with lows in the low to mid-60s and a lingering
threat of rainfall (70% to 90% chance). Partial sunshine follows
for Tuesday with a continued threat of shower and thunderstorms
(60% to 80% chance). Temperatures will cool further on Tuesday,
with highs near 80F.
.LONG TERM...(Tuesday night through Sunday)
Issued at 508 AM EDT MON SEP 22 2025
The long-term forecast period begins Tuesday evening with a
dampening 500 hPa trough over the Great Lakes, while potent
Pacific energy carves a deep trough across the Central Plains. The
dampening trough is forecast to form a weak closed low by
Wednesday, which then intensifies near or over Lake Michigan as
Pacific energy streams into it from the southwest. Substantial
model spread exists regarding the interaction of these features.
It is uncertain how much Pacific energy will feed into the Great
Lakes system versus closing off into a separate upper low that
could dive into the Gulf Coast states late in the week.
Regardless of the eventual outcome, rounds of showers and
thunderstorms are expected to traverse the forecast area each day
until the primary upper-level energy ejects and removes the
seasonably humid airmass. The wettest days currently appear to be
Wednesday and Thursday. Afterward, the upper-level system (or
systems) should be positioned to allow drier air to return to
eastern Kentucky. Widespread 5-day rainfall totals of 2 to 3.5
inches can be expected through Friday, though localized amounts of
4+ inches cannot be ruled out. Areas that have ongoing dry to
moderate drought conditions are favored to receive some of the
heaviest rainfall totals, so the rain should be beneficial for
many. Temperatures will cool gradually through Friday, with highs
returning to the 70s and nighttime lows falling into the 50s.
Widening diurnal temperature ranges and a slow warming trend for
daily highs are favored from Saturday onward as the drier air
returns.
Previous discussion 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 06Z TAFS through 06Z Monday night)
ISSUED AT 147 AM EDT MON SEP 22 2025
Through the remainder of the night, generally VFR conditions are
expected at the TAF sites under variably cloudy skies. Fog is
likely in the typical prone valley locations through 13Z with MVFR
to IFR reductions. There is also a low chance for a shower or
even a stray thunderstorm, primarily toward and north of I-64 (a
PROB30 group was included at SYM). Otherwise, additional showers
and storms are anticipated during the day on Monday, most
widespread during the afternoon and evening. Reductions to MVFR
or lower are anticipated within any stronger convection while
associated winds could gust 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 around 10KT or less through the day.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...GEERTSON
LONG TERM...GEERTSON/CMC
AVIATION...GEERTSON/JP
Source:
JKL issues Area Forecast Discussion (AFD) at Sep 22, 5:08 AM EDT---------------
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