952
FXUS63 KJKL 030115
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
915 PM EDT Tue Sep 2 2025

.KEY MESSAGES...

- Multiple rounds of showers and thunderstorms are likely across
  the area through Thursday and again on Saturday, with the
  highest probabilities immediately ahead of a cold front on
  Thursday.

- A few of the storms on Thursday afternoon may be strong to
  severe, especially in southern and eastern portions of the
  forecast area.

- Widespread rainfall totals between 0.5 to 1.0 inches is likely
  with locally higher totals up to 1.5 inches are possible in the
  Cumberland River basin.

- Below normal temperatures are expected through the period, and
  the coolest low temperatures are forecast next weekend behind a
  secondary cold front.

&&

.UPDATE...
Issued at 915 PM EDT TUE SEP 2 2025

Convective activity has mostly dissipated, with the exception of
Bell and Harlan counties. With continued warm advection through
the overnight and the region lying with the PVA region of an
approaching disturbance, will keep at least slight chance of
storms in the forecast through the overnight, at least for now.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 335 PM EDT TUE SEP 2 2025

Isolated showers and thunderstorms continue at mid-afternoon
across most locations east of I-75 and more scattered to the west
around Lake Cumberland. Temperatures are seasonable for early
September, ranging from the upper 70s to lower 80s outside of
convection and generally in the 70s at locations recently impacted
by convection. The latest analysis shows a surface trough nearly
parallel to the southern shore of the Ohio River from Huntington,
WV west southwestward into the Jackson Purchase while an upper
level trough axis extends southward across the eastern CONUS from
a ~572 dam low (situated just north of Lake Ontario). Immediately
south of the surface trough axis, the SPC mesoanalysis shows
~500-1250 J/kg of MLCAPE across all of eastern Kentucky except in
the far northeast where there is less. PWATs are seasonably moist
at 0.8 to 1.3 inches, northeast to southwest. It is within this
warm, moist, and moderately unstable, uncapped air mass that we
find the ongoing convection.

This unsettled weather pattern will continue through the duration
of the short-term forecast period. The 500 hPa low continues to
lift northward and is eventually absorbed by a much more potent
northern stream 500 hPa low digging southward from northern
Canada. At the surface, the trough over the Lower Ohio River will
slowly dissipate tonight. Meanwhile, two perturbations riding
through the upper-level trough will pass through the area over the
next 24 hours: one this evening and overnight, and another during
the day on Wednesday. After the diurnally induced convection
diminishes this evening, the disturbance will keep spotty
convection in the forecast overnight, especially closer to the
Virginia-Kentucky border. There will then be a renewed threat of
convection on Wednesday, coincident with the passage of the next
upper-level disturbance. After a lull for most of Wednesday
evening/night, a third disturbance embedded in the flow aloft
could bring a renewed threat of convection toward daybreak on
Thursday, especially closer to the I-64 corridor. While rainfall
could be briefly heavy with the stronger convection, abnormally
dry to moderate drought antecedent conditions and only seasonable
moisture levels in the atmosphere will strongly mitigate high
water concerns.

In sensible terms, look for hit-and-miss showers and
thunderstorms with briefly heavy rainfall possible. The most
widespread activity is expected during the afternoon to mid-
evening hours. The focus for the most widespread activity through
this evening appears to be mainly southwest of US-421, whereas the
focus for most of the convection on Wednesday appears to be east
of the Escarpment. Rainfall amounts could vary dramatically over
just a few miles from little or nothing up to 1 to 2 inches in
the heavier shower and thunderstorms activity. Outside of the
aforementioned prime peak heating hours, an isolated shower or
storm cannot be ruled out at other times, though many places will
stay dry. Temperatures will be seasonable as well with highs
primarily in the upper 70s to lower 80s and lows in the mid 50s to
around 60. Fog is probable tonight in the sheltered river valleys
and in at least some areas that see rainfall this afternoon and
evening. Fog potential is less certain on Wednesday night.

.LONG TERM...(Thursday through Tuesday)
Issued at 520 PM EDT Tue Sep 2 2025

Active, wet weather will continue across Eastern Kentucky for the
start of the long term forecast period. As a large upper level low
spins in place north of the Great Lakes, a series of disturbances
will rotate around it and drag a couple of cold fronts through the
region. The first of these fronts is poised to produce widespread
showers and thunderstorms across the forecast area on Thursday. The
primary impact from this first system will be the highly-beneficial
rainfall that it produces, although a few stronger thunderstorms
cannot be ruled out on Thursday afternoon. The second system will be
working with a drier airmass than the first; it will likely produce
less widespread rainfall as a result. While guidance disagrees upon
the exact timing of this second frontal passage, the late week
system is more likely to tangibly drop temperatures than Thursday`s.
Thus, the end of the long term forecast period will be defined by
cooler and drier conditions.

When the period opens on Thursday morning, a broken line of
convection will likely be approaching Eastern Kentucky from the
northwest. The evolution of said convection will likely play a role
in how Thursday`s sensible weather forecast evolves. Seasonably deep
moisture profiles (PWATs approaching 1.5-1.6 inches) and frontal
forcing should allow convection to continue throughout the day, and
model soundings indicate between 30 and 35 knots of effective bulk
shear across Eastern Kentucky on Thursday afternoon. The Storm
Prediction Center has accordingly outlined much of the forecast area
in a Marginal (Level 1/5) Severe Weather Outlook for Thursday
afternoon/evening, but questions linger regarding the thermodynamic
environment in this time frame. It is possible that early-day cloud
cover limits the amount of diurnal warming realized on Thursday
afternoon, and model soundings indicate a stable layer near the
surface as the morning round of storms enters northwestern portions
of the forecast area. This early round of storms could lead to
differential heating across the forecast area, which could then work
to enhance thunderstorm chances on the meso-scale. Northwestern
portions of the forecast area could struggle to warm above the mid-
70s, but southern and eastern counties will see forecast highs near
or above 75. The currently-available model guidance depicts up to
1500 J/kg of MUCAPE in our southeastern counties, and this mirrors
where SPC has drawn their highest probabilities for damaging wind
gusts. Subtly curved low-level hodographs suggest that these storms
may need to be watched closely, and we will need to closely monitor
trends in convective parameter spacing as this event enters the
temporal range of higher-resolution forecast guidance.

Regardless of convective intensity, Thursday`s showers/storms are
poised to bring much-needed rainfall to the region. Storm total QPF
remains in the 0.5 to 1.25 inch range, with the highest totals in
southwestern portions of the forecast area. Given that much of the
region is currently outlined in D0 (abnormally dry) conditions, and
the Lake Cumberland region is in D1 (moderate drought) in the latest
US Drought Monitor data, this rain will prove highly beneficial.
Even if locally-higher totals emerge with stronger convection, the
ground should be able to absorb this precipitation efficiently, and
widespread hydrological issues are not currently expected.

On Thursday night, skies will clear and temperatures will briefly
cool off in the wake of the first front. Expect lows to dip down
into the 50s, although lingering cloud cover could keep MinTs closer
to 60 in southeastern portions of the forecast area. Wet grounds
could lead to patchy fog formation overnight into on Friday morning,
but midlevel height rises associated with shortwave ridging point
towards a sunnier and warmer Friday afternoon, with highs recovering
into the 80s area-wide. Return flow ahead of the second disturbance
could prove gusty on Friday afternoon, although model spread begins
to increase around this time frame.

At some point between Friday night and Saturday night, a second
shortwave disturbance will rotate around the upper level low and
push another cold front into the region. The GFS brings this second
front in faster than the European models, and this discrepancy leads
to differing amounts of atmospheric recovery in between systems.
PoPs have trended upwards on Saturday in the baseline NBM guidance
compared to this time yesterday, but the greatest values remain in
SE KY, where NW flow typically leads to orographic lifting
enhancements. Nevertheless, the most noticeable impacts with this
secondary FROPA will likely be its reinforcing shot of cool, dry
air. Highs through the end of the long term forecast period should
stay in the mid 70s, with overnight ridge/valley low temperature
splits a few degrees above/below 50 degrees. Beyond then, models
diverge even more, although there are hints of more unsettled
weather on the horizon for early next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 715 PM EDT TUE SEP 2 2025

Convection will diminish through the evening, allowing for some
fog to develop, especially in the favored in river valleys, though
some impacts cannot be ruled out at TAF terminals that experience
rainfall this afternoon/evening. The SME and LOZ TAF sites have
the greatest opportunity for experiencing convection through mid-
evening while that threat is lowest at SJS. Another round of
showers and storms may develop late tonight into early Wednesday
morning but may be favored to stay largely southeast of the
terminals. Winds will be light and variable, except for the
potential for brief gusty winds with convection.

&&

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

&&

$$

UPDATE...CMC
SHORT TERM...GEERTSON
LONG TERM...MARCUS
AVIATION...CMC