916
FXUS63 KJKL 040850
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
450 AM EDT Fri Sep 4 2026

.KEY MESSAGES...

- It will continue to be hot through this evening, with maximum
  heat indices as high as 106 degrees.

- Showers and thunderstorms are possible at times from this
  afternoon through early next week. Storms today and Saturday
  could produce damaging wind gusts and torrential downpours.

&&

.SHORT TERM...(Today through Saturday)
Issued at 430 AM EDT FRI SEP 4 2026

08Z sfc analysis shows high pressure centered southeast of
Kentucky holding in place and controlling the weather over the
central Appalachians. For this night, this has meant light to
calm winds, clear skies, and a bit of river valley fog for the
JKL CWA - though the extent of this and any ridge to valley
temperature splits are limited by a base of high dewpoints.
Accordingly, readings are generally in the 70 to 75 degree range
offering little relief from the ongoing heat. Meanwhile, dewpoints
are generally in the sticky low 70s.

The models, and their individual ensemble suites, are in excellent
agreement aloft through the short term portion of the forecast.
They all depict a 5h ridge centered over northwest South Carolina
and southeast Tennessee to start the period. This dome of heat
will weaken into the weekend as influence from the trough making
up eastern pole of a developing omega block over the continent
edges into Kentucky for Saturday. This process brings northwest
flow at mid levels to the JKl CWA along with the threat for ridge
running minor waves that could spawn MCS activity or just allow
for general thunderstorms as the heavier subsidence retreats to
the southwest. Falling heights at 5h late in the period will be
the death knell of the ridge (at least for a short while) and its
oppressive heat. On account of the minuscule model spread, mainly
unadjusted NBM data was used for the forecast grids. However,
some small enhancements were made to highlight terrain details in
temperatures tonight. Meanwhile, in addition to including the most
current consensus of the CAMs, PoPs were adjusted up this
afternoon to at least the 10 to 15 percent range. The convective
threat appears adequately represented for Saturday with just the
CAMs additions.

Sensible weather will feature another warm day with only limited
cooling from scant convection this afternoon. Accordingly, another
day of Heat Advisory conditions unfolds for the bulk of the JKL
CWA. For tonight, despite height falls and slightly cooling 85h
air late, sfc temperatures will still be quite warm with most
places not falling below 70 degrees through dawn. With this,
expect some river valley fog once again. Saturday will be a
different type of day with better upper support and less
subsidence aloft to allow for stronger storms likely affecting
more of the area. High instability and an improving wind field
will also mean a potential for severe wind gusts with any
organized storms that afternoon and evening. The better coverage
of convection should also keep temperatures a category or more
cooler than those of today - bringing some relief to most.

The main adjustments to the NBM starting point included limited
terrain details in the upcoming overnight temperatures. As for
PoPs - had them peak near 15 percent even in places that the NBM
and latest CAM runs kept dry due to the uncertainty and lack of a
key focusing mechanism for convective initialization.

.LONG TERM...(Saturday night through Thursday)
Issued at 450 AM EDT FRI SEP 4 2026

The extended portion of the forecast remains on track with better
rain chances at the beginning of the period owing to a sfc
boundary nearby, or moving through the JKL CWA followed by
another extended dry patch on account of 5h ridging building back
over the area for much of the upcoming week. Only late in the
period does the northern stream appear to push the upper ridge
off to the southwest enough to have an impact on the weather for
eastern Kentucky - though some model discrepancies creep in by
this time lowering overall forecast confidence.

The previous long term discussion follows:

Saturday will see troughing associated with an upper low over the
St Lawrence Valley/Quebec, extending into the ne conus to the Mid
Atlantic. By late Friday night into Saturday morning, the
aforementioned cold front will sag s through much or all of ern
Kentucky, providing another focus for showers and storms. There is
still significant model disagreement regarding the timing and
extent of convective coverage associated with this frontal
passage, resulting in NBM PoPs likely being a bit underdone at
least at times compared to true rain chances, although uncertainty
remains too high to refine these PoPs at this time. Adding to
this uncertainty, some deterministic guidance depicts MCS activity
or its remnants diving se out of the Midwest during the day
Saturday, following the periphery of the ridge. Although rain
appears likely at some point on Saturday, the details continue to
remain unclear at this time. The NBM continues to keep pops
generally low, maximized mainly in the 20-50% range, to account
for this. Meanwhile, nly postfrontal winds will keep highs in the
upper 80s on Saturday afternoon, with low 90s near the KY/TN line.

Rain chances look lower from Sunday onward as the upper level ridge
begins to expand ewd. With surface high pressure building ne of
the forecast area, nely winds will keep Sunday`s temperatures
cooler than at the start of the period (but still quite warm).
Dewpoints look to be modestly lower as well (in the 60s rather
than the 70s), and this drier pattern will continue through the
end of the period. Even so, Labor Day looks to be quite warm, with
above average temperatures in the upper 80s expected across the
area. Other than this, the weather will be quite pleasant and
sunny, with the exception of an isolated diurnally driven
thunderstorm in s or se.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 155 AM EDT FRI SEP 4 2026

Overall, VFR conditions will prevail for the bulk of the period
with the exception being valley fog. This fog likely affects some
locations through around 14Z, with IFR or lower reductions in the
worst cases. At this time, confidence is still not high enough to
include it at any of the TAF sites. Diurnally driven cumulus
develop between 16Z and 18Z with stray showers or storms possible
into the evening - though probably missing any TAF sites. Winds
will be light and variable, outside of any storms.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.

&&

$$

SHORT TERM...GREIF
LONG TERM...ILN/GREIF
AVIATION...JP/GREIF