346
FXUS63 KJKL 130719 AAB
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
319 AM EDT Wed May 13 2026

.KEY MESSAGES...

- A cold front is expected to bring isolated to scattered showers
  and perhaps a few thunderstorms to the region today. An isolated
  strong storm cannot be ruled out nearer to the WV border.

- Patchy frost is possible late Thursday night into early Friday
  morning in sheltered rural valleys and hollows, away from
  mainstem rivers.

- Additional shower and thunderstorm chances arrive to start the
  weekend followed by a pattern shift that favors temperatures 10
  to 15 degrees above normal.

&&

.UPDATE...
Issued at 726 PM EDT TUE MAY 12 2026

No changes made to the forecast aside from adding in the latest
obs and aviation grids ahead of the 00Z TAF issuance. Grids have
been saved and sent.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 424 PM EDT Tue May 12 2026

Eastern Kentucky is under the influence of a broad area of surface
high pressure this afternoon, with sunny skies and efficient diurnal
processes observed across the area. Mixing has resulted in breezy,
but erratic, wind gusts in the northeastern half of the forecast
area and widespread temperatures in the 70s. Dewpoints have mixed
down into the upper 30s at some of the region`s valley observation
sites, although they remain in the 40s across the southwest and on
ridgetops. Given the persistence of clear skies through sunset,
those same hollows may decouple after sunset this evening. This
marks the greatest deviation from the baseline NBM guidance for this
evening`s forecast.

Expect the sheltered and shaded valleys east of Interstate 75 to
drop down into the mid 40s as radiational cooling takes roots.
Patchy fog may develop along the Cumberland and the South Fork of
the Kentucky around midnight, especially given that dewpoints are
relatively higher there this afternoon. However, tonight is not
necessarily the typical overnight ridge-valley split forecast for
our forecast area, as overnight lows are progged to occur just after
midnight rather than early tomorrow morning. A well-defined
shortwave trough and its associated surface low will pass through
the Great Lakes overnight into tomorrow morning. As they do so, they
will drag a surface cold front towards the commonwealth and yield a
tightening pressure gradient.

The resultant strengthening/deepening southwesterly flow in the
lower portions of the column is expected to re-couple the ridges and
valleys by dawn tomorrow. Breezy wind gusts between 20 and 30mph may
mix down to the surface as these features approach, and a narrow
tongue of prefrontal moisture is expected to advect into the
forecast area ahead of the boundary. As the shortwave trough
propagates east, the front gets dragged east-southeast across the
forecast area. Scattered shower chances accordingly spread across
the CWA after 8AM, with the greatest AM chances falling closer to
the parent trough in the northern half of the forecast area. Given
that forecast PWATs are only around 1.00 inches and that model
soundings resolve a prominent layer of dry air around 700mb, QPF
with this initial round of activity will be light. Furthermore, the
lack of alignment with the diurnal instability curve will limit the
potential for widespread thunderstorms within this initial round of
activity. A rumble of thunder or two cannot be ruled out, but severe
weather is unlikely in the Bluegrass tomorrow.

Forecast guidance has been trending slower with the actual frontal
passage tomorrow, which will give southern and eastern portions of
the CWA an additional (but conditional) chance for thunderstorms on
Wednesday afternoon/evening. The persistence of prefrontal west-
southwesterly flow and the potential for diurnal mixing to produce
pockets of sun tomorrow afternoon could result in 500-1000 J/kg of
SBCAPE east of I-75. While the more robust dynamic support aloft
will be relegated to the NE of the forecast area in West Virginia,
HREF joint probabilities for marginally-favorable convective
parameter spacing (>500 SB-CAPE, <-25 SB-CIN, and 30 knots of bulk
shear) are in the 60-80% range tomorrow afternoon southeast of a
line stretching from Paintsville to Williamsburg. The highest
probabilities are in Pike County, where SPC has outlined a Marginal
(Level 1/5) Risk for Severe Storms, but widespread severe weather is
not anticipated. A few storms may produce locally gusty winds, but
the primary impact from this second round of activity in SE KY will
be a highly-beneficial bolstering of storm total QPF. Given the
convective nature of the rain, observed rain totals will be
spatially variable and streaky, but a few locations may get lucky
and experience a wetting rain (>0.10 inches).

Once frontal passage occurs tomorrow evening, flow throughout the
column shifts to a more northwesterly orientation and begins to
advect a cooler and drier airmass into the forecast area for
Wednesday night. If winds slacken a bit more than what is currently
forecast and grounds are wet from the earlier activity, another
night of valley fog is plausible. However, a lobe of vorticity
moving around the back side of the parent troughing aloft could allow
for a low-level stratus deck to build into the Big Sandy River
Basin. Thus, confidence was not high enough to explicitly include
fog in Wednesday night`s grids with this forecast package.

.LONG TERM...(Thursday through Tuesday)
Issued at 322 PM EDT TUE MAY 12 2026

There is reasonable agreement with the upper level pattern for the
long range period. Thursday, a cold front will have shifted
southward and northwest flow will follow in the wake. This will
provide a dry and cooler than normal day, with highs in the mid to
upper 60s. High pressure and mid-level height rises will allow
for clear and calm conditions to set up for Thursday night. This
could lead to frost and or fog across the area depending on
lingering moisture from Wednesday. Either way this later frost
potential could lead to some agricultural concerns given the late
nature of these colder valley temperatures.

This cooler pattern is quite short lived. Most of Friday looks to be
dry, with temperatures quickly rebounding into the mid to upper
70s, as high pressure sags southeastward and return flow takes
hold. Then another upper level shortwave ejects eastward and warm
front pushes northward. This will set the stage for showers and
thunderstorms across parts of the Commonwealth late Friday night
into Saturday. The best chances for rainfall will be mainly north
of the Hal Rogers Parkway and KY80, but in general we are looking
at rain chances peaking at 30-50 percent.

The pattern shifts to being quite warm across eastern Kentucky late
this weekend into early next week. This as height rises build
northwest, with 588mb mid-level heights surging into eastern
Kentucky. The deterministic NBM is on the hotter side of guidance
showing temperatures in record high territory for the whole month
of May, with the primary ensemble model blends showing most of
the area at less than a 40 percent chance of seeing greater than
90 degrees on Monday for example. There is also uncertainty
Tuesday, with how quickly a approaching wave and cold front make
it eastward into the Ohio Valley. Either way there is a good shot
for highs in the mid to upper 80s Saturday through Tuesday, with
some areas getting closer to 90 degrees especially Monday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 235 AM EDT WED MAY 13 2026

VFR conditions were prevailing across eastern KY including the
TAF sites with the 06Z issuance. Prevailing VFR is expected to
continue through the period with one caveat. A cold front will
cross the area on Wednesday, bringing an increase in low and mid
level clouds as well as isolated to scattered showers and perhaps
a few storms generally between 12Z and 00Z. Within the heavier
showers or any storms some brief reductions to MVFR are possible.
Clouds decrease by the last 6 to 9 hours of the period. Winds are
currently light an variable or south to southwest at less than
10KT. After about 09Z, as the gradient increases and the front
nears, winds will become south to southwest a generally 5 to 10KT,
before increasing to 10 to 15KT between 12Z and 18Z and becoming
more westerly as the front nears. Winds trend to the northwest to
north between 18Z and 00Z as the front passes with 10 to 15KT
sustained speeds on average. Some gusts as high as 20 to 25KT are
anticipated during the daylight hours. The pressure gradient
begins to slacken as high pressure builds in from the MS Valley to
end the period and should result and sustained winds should drop
below 10KT with less gusts before the end of the period.

&&

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

&&

$$

UPDATE...VORST
SHORT TERM...MARCUS
LONG TERM...DJ
AVIATION...JP