JKL issues Area Forecast Discussion (AFD) at Sep 24, 4:50 AM EDT787
FXUS63 KJKL 240850
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
450 AM EDT Wed Sep 24 2025
.KEY MESSAGES...
- Multiple rounds of showers and thunderstorms will bring times of
soaking rains this week. While beneficial for the drought, this
rain could cause localized flash flooding, especially later today.
- A few thunderstorms today could become strong, with damaging
wind gusts as the main threat. The potential for these storms
will depend on how much the atmosphere can destabilize during
the day.
- A wet and unsettled pattern will continue through Friday before
cooler and drier, fall-like weather arrives for the weekend.
&&
.SHORT TERM...(Today through Thursday)
Issued at 450 AM EDT WED SEP 24 2025
At 850z, regional radar shows a band of weakening convection
lifting over far east Kentucky. This activity is associated with
a subtle shortwave perturbation and vorticity maximum aloft, but
it is weakening as it moves into an increasingly stable
environment. Other disturbances are noted aloft streaming from the
parent positively-tilted 500 hPa trough extending from Southern
Quebec southwest into the Southern Rockies. These pockets of
energy are forcing much of the disorganized convection to our west
and southwest over Kentucky and Tennessee. A weak ~1012 mb
surface low is developing over northeast Texas ahead of the
aforementioned trough and is tracking northeast along a wavy
frontal zone stretching to Detroit and then off Cape Cod.
The main story during the short term will be rounds of showers
and thunderstorms as the 500 hPa trough translates eastward and
the primary surface low tracks northeast today into the Mid-
Mississippi Valley, across Kentucky tonight, and into the
Northeast U.S. on Thursday. This system will drag the wavy front
toward the northwestern portion of the forecast area by Thursday
morning. However, that front's progress will be slowed by
another, weaker surface wave developing along the boundary just
ahead of the 500 hPa parent trough axis. Thus, passage of the cold
front over eastern Kentucky is delayed until Thursday evening. A
modest southerly fetch will promote PWATs rising to between 1.6
and 1.9 inches today. This moisture, combined with skinny CAPE
profiles (500 to 1500 J/kg of MLCAPE) and a deep warm cloud layer,
will be supportive of heavy rainfall rates. Tropospheric flow is
strong enough to support progressive cell motions (~25 to 30 kts),
which should limit the overall flash flooding threat. However, a
nearly unidirectional deep-layer flow parallel to the baroclinic
zone to our northwest could aid in training convection. General
rainfall amounts of 1 to 2 inches are likely through 12Z Thursday.
However, some locales may only receive a few tenths of an inch,
while others could see over 3 inches where training occurs. Recent
CAM guidance has been consistently generating the highest
rainfall totals over the northwestern third of our forecast area,
where drought conditions are ongoing, though some models have
suggested a second maximum over southeastern Kentucky. The Weather
Prediction Center (WPC) has maintained a Slight Risk in their
Excessive Rainfall Outlook (ERO) for isolated to scattered flash
flooding. Trends will be monitored for any potential need for a
Flood Watch. A threat also exists for a few stronger thunderstorms,
with gusty winds as the primary concern. Otherwise, looking ahead
to Thursday, the better moisture will depart with the exiting low
pressure. However, a vorticity lobe in the base of the
approaching trough axis and convergence near the cold front will
aid in the development of scattered to numerous showers and
possible thunderstorms. Dry mid-level air and meager CAPE
profiles will tend to limit convective vigor and rainfall rates on
Thursday.
In terms of sensible weather, expect rounds of showers and
thunderstorms interspersed with breaks of sunshine and periods of
dry time. The most widespread shower and thunderstorm activity is
expected through midday across all of eastern Kentucky. This
afternoon and evening, activity will be most focused in counties
along and north of the I-64 corridor. Another widespread round of
organized showers and storms can be expected overnight. More
sporadic, diurnally-modulated showers and possible thunderstorm
activity are anticipated for Thursday. Temperatures will be mild
with highs in the mid 70s to near 80 both today and Thursday while
overnight lows remain in the 60s.
.LONG TERM...(Thursday through Tuesday)
Issued at 241 PM EDT TUE SEP 23 2025
For Thursday, a positive upper trough will move into the area with
jet dynamics producing fronto-genetic forcing along an approaching
frontal boundary. A band of showers and storms will move across the
region producing heavy rains with greatest potential of flooding
near the KY/VA and KY/TN statelines. Severe threat is marginal and
dependent on any breaks in the cloud to enhance instability.
Ensemble composite analysis shows best CAPE/SHEAR across the far
south/southeast sections, southward into the Tennessee valley.
For the extended period from Friday through early next week shows a
large difference in solutions from the deterministic GFS and ECMWF.
Based this period on the Ensemble Cluster Analysis solution which
pulls a positive tilted upper trough across the region Friday which
becomes quasi-stationary over the southeast/eastern United States.
For Friday, frontal boundary will be east of the area with enough
wrap-around moisture to produce a low chance of showers near the
KY/VA stateline. Otherwise, plenty of low-level moisture with mostly
cloudy sky.
For Saturday, the near stationary trough axis across the eastern
United States with wrap-around moisture continuing to produce a
chance of showers especially near the KY/VA stateline with sky cover
varying from partly cloudy to mostly cloudy. Sky becomes mostly
clear Saturday night allowing for good radiational cooling
conditions so will modify the mins for the valley/ridge temperature
differences.
For Sunday and Monday, upper trough axis remains east/southeast of
the area with the region under northerly/northeast flow. Partly
cloudy to mostly clear sky with mostly dry conditions anticipated.
Ensembles/deterministic models hint at possible inverted surface
trough across the area so can not rule out a shower near the KY/VA
and KY/TN stateline due to the proximity of the upper
trough/wrap- around moisture/limited instability. For Tuesday,
persistent and weakening upper trough over the southeast United
States. Confidence is too low to include a chance of showers and
expect dry conditions.
Sky remains mostly clear to partly cloudy at night allowing for good
radiational cooling conditions so will modify the mins for the
valley/ridge temperature differences.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 202 AM EDT WED SEP 24 2025
Outside of a line of convection crossing the I-75 corridor area
(including KLOZ) and fog in some of the deeper valleys, VFR
conditions were noted across the area at TAF issuance. As that
convective line presses east, deteriorating conditions will
follow as shower and thunderstorm coverage increases. Showers and
thunderstorms, coupled with low CIGs and poor visibility, will
lead to near LIFR, IFR and MVFR conditions for much of the
remainder of the period. Generally light, variable winds will
become southerly at 5 to 10 kts after sunrise; however, gusty and
erratic winds could accompany any thunderstorm.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...GEERTSON
LONG TERM...DH
AVIATION...GEERTSON
Source:
JKL issues Area Forecast Discussion (AFD) at Sep 24, 4:50 AM EDT---------------
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