258
FXUS63 KJKL 102112
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
512 PM EDT Mon Aug 10 2026

.KEY MESSAGES...

- Showers and thunderstorm chances will persist through the end of the
  week. The greatest coverage is expected from Tuesday through
  Friday. Some of those storms could arrive as organized clusters
  with a potential for strong to damaging wind gusts.

- Isolated to scattered instances of excessive rainfall may occur where
  storms are most persistent, leading to elevated concerns for
  flooding - especially for mid-week.

- A Flood Watch is in effect for northeastern Kentucky until 8 AM
  EDT on Wednesday, primarily for flash flooding.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 512 PM EDT MON AUG 10 2026

All is fairly quiet, but warm and humid across eastern Kentucky late
this afternoon. Air temperatures range from the mid 80s to around
90F while dew points in the lower to mid 70s make it feel more like
the 90s to around 100F. Thus far, the diurnal cumulus field has
remained largely subdued, aside from a couple of rogue sprinkles and
very isolated thunderstorms. The greater regional radar mosaic shows
an MCS over northwest Virginia up into southeast Pennsylvania. It
has laid out a pronounced outflow boundary extending from
Charleston, WV to Columbus, OH. Most notably though, this is the
first of multiple MCSs in the days ahead amidst a synoptic-scale WNW
flow pattern where multiple perturbations passing aloft will
interact with a sultry and unstable atmosphere south of a stalled
boundary near the Great Lakes.

In this setup, large run-to-run model disagreements have been noted
among the CAMs, and none of the 12z HREF member solutions have
managed to generate a semi-accurate solution even for the first 8
hours of the period. The disparities and resulting sensible weather
forecast have been vast -- the 12Z FV3 (and to a lesser degree the
HRRR) were too far to the northeast with the initial MCS and would
have the outflow still over West Virginia late tonight, while the
NAMNest overconvected and would have the outflow blasting all the
way to Paducah, Kentucky by that same time. Meanwhile, the RRFS and
REF members have generally been somewhat closer to reality thus far,
though still too far northeast by perhaps 100 miles with the initial
MCS and likely to aggressive with the overall convection. All of the
REFs members do largely agree, however, on the aforementioned
outflow becoming a point of initiation for renewed convective
development heading into this evening. The members then show this
convective activity backing southwest into a high-instability, high-
moisture air mass over the Commonwealth this evening and overnight.
The latest RAP mesoanalysis shows this high-instability air mass
across our region with 3500 J/kg of SBCAPE in the east up to ~5000
J/kg of SBCAPE near Lake Cumberland. So while steering flow will
remain WNW, the unstable WSW low-level flow should tend to support
convective complexes wanting to build back into the area of high
instability over eastern Kentucky (as much of the instability will
remain after sunset).

The backing nature of the storms against the deep-layer westerly
flow will tend to support storms repeatedly building into nearly the
same locations as the outflow tries to work southwestward. This
should limit overall potential for straight-line wind gusts with
this potential system. However, given high PWATs already between 1.5
and 2.0 inches and the potential for localized PWATs pooling to
higher amounts with strong IVT on a westerly 20 to 30 kt 850 hPa
jet, torrential downpours are likely to occur in stronger cells. If
this convection persists for too long across a given area, flash
flooding is possible even in areas that are relatively dry going
into this event. Thus a Flood Watch has been hoisted for those
counties across eastern Kentucky where there is the greatest
confidence in heavy rainfall tonight. Additional westward expansions
appear increasingly probable in future updates. The Flood Watch is
currently in effect through Wednesday morning, as some data
supported a bit of a pause in the activity, and by that time the
mesoscale environment and favored track for MCSs becomes quite
uncertain. However, if the longer-range guidance proves close to
accurate, the Flood Watch will likely need to be extended in time
and/or reissued.

Tonight`s convection will heavily dictate the mesoscale environment,
ensuing MCS evolution, and the areas most heavily impacted on
Tuesday and Tuesday night. If there is enough of a break in the
clouds and precipitation on Tuesday, the risk of severe convection
will be elevated, especially across the northern half of the CWA
where SPC`s Slight Risk is coincident with a hatched area for
significant severe wind gusts. There is also a non-zero risk of a
brief spin-up tornado should stronger convective scenarios unfold.
That conditional severe threat, while quite notable, coincides with
a Moderate Risk ERO across northeast Kentucky. At present, only a
small portion of our CWA is in the Moderate Risk (Fleming and Rowan
counties), but further expansions cannot be ruled out. Within the
Flood Watch area, the 25th to 75th percentile of the REFs would
support a widespread ~0.5 to ~3.5 inches of rain. Ensemble max
values of 4.0 to 5.5 inches through 12Z Wednesday represent possible
worst-case scenarios. Those with interests in flood-prone areas are
encouraged to monitor later forecasts.

.LONG TERM...(Wednesday through Monday)
Issued at 459 PM EDT MON AUG 10 2026

Active weather will continue in the long term period, with multiple
bouts of thunderstorms probable. However, confidence in details is
still very elusive.

We will start the period still under west northwest flow in the mid-
upper levels, near the southern edge of faster flow, and with
subtropical ridging just to our south southwest. A very warm and
humid surface air mass will remain in place and give considerable
instability. This completes the setup for MCSs to develop where
there`s enough focus from initiating features. The forecasting
problems are that these features are relatively weak in the big
scheme of things, and also that future convection relies in part on
the evolution of difficult to forecast prior convection. Have used a
broadbrushed forecast for POP through Friday based on blended
models.

The GFS and ECMWF both show potential for a weak cold front to slip
south southwest through the JKL forecast area by the weekend as a
weak low rotates through a northeast CONUS trough and enhances the
upper level flow over the Great Lakes and Ohio Valley. Should this
come to pass, there could be a break in the precip potential at the
start of the weekend. Any relief from the muggy air mass would
probably be minimal, as the upper troughing quickly departs and
ridging builds into our area from the southwest during the weekend
and supports hot and humid weather.

Models then show another impulse moving through the faster flow to
our north and northeast, which suppresses the ridging back to the
southwest early in the new week. This would allow another weak cold
front to push in from the north with an increase in the POP in the
neighborhood of Monday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 227 PM EDT MON AUG 10 2026

VFR conditions prevailed over all TAF sites at the start of the
18Z forecast period. A cumulus field is noted across the area with
cloud bases generally at 3-4 kft AGL. An MCS tracking from OH into
WV is laying out an outflow boundary just northeast of the state.
If convection can refire along this boundary, a new MCS could
develop and drop across the CWA later this evening and tonight.
Included PROB30 groups with this update, though forecaster
confidence is rather low. Away from any storms, winds will be
around 10kts or less, generally from the southwest.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Wednesday morning for KYZ044-052-104-106-107-
109-110-119-120.

&&

$$

SHORT TERM...GEERTSON
LONG TERM...HAL
AVIATION...GEERTSON