Ajax, Kentucky Weather Forecast Discussion

357
FXUS63 KJKL 181927
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
327 PM EDT Thu Sep 18 2025
.KEY MESSAGES...
- Mainly dry weather looks to persist through the weekend.
- Temperatures will continue to be above normal through this
  weekend and into next week.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 302 PM EDT THU SEP 18 2025
A mix of fair-weather cumulus and bright sunshine prevails across
eastern Kentucky this afternoon. Temperatures are rising through
the 80s at issuance time and should attain highs in the mid to
upper 80s in most places over the next couple hours. The pleasant
conditions are due to broad surface high pressure situated over
the Ohio Valley, nearly collocated with a ridge axis oriented from
the Southern Appalachians northwestward into the Upper Great
Lakes. Meanwhile, an upper-level low and its weak surface
reflection are spinning over the Northern Plains.
Through the short-term, these features will gradually propagate
eastward, resulting in a slow departure of the high pressure while
surface/upper lows drift into the Upper Midwest. Locally, a
stable, dry low-level airmass will persist through Friday night as
eastern Kentucky remains firmly under the influence of the high-
pressure system. However, an increase in mid-to upper-level
moisture advection is expected late Friday and Friday night,
leading to an increase in cirriform clouds.
In terms of sensible weather, expect fair conditions to persist,
with the potential for nighttime and morning valley fog in favored
locales. Temperatures are forecast to fall into the mid-50s in
valleys and the low 60s on ridges overnight while thermometers
consistently reach the mid to upper 80s each afternoon. A few of
the warmest locations could approach 90F.
.LONG TERM...(Saturday through Thursday)
Issued at 325 PM EDT THU SEP 18 2025
Little change in the extended, with ridging building above the
eastern CONUS ahead of a developing trough in the central Plains.
Under increased upper-level heights, the warmest temperatures over
the next week come Saturday. Expect highs in the upper 80s to low
90s, and overnight low temperatures generally in the upper 50s to
low 60s. Temperatures gradually decrease by 1-2 degrees each day
Sunday through Tuesday, when the next disturbance looks to
encroach on the area.
As the wave in the Plains begins to develop, low-level flow will
become southerly and begin to advect moisture along the western side
of the Cumberland Mountains. Sunday features 10-20% PoPs in the
afternoon hours to reflect the potential for some low-coverage
afternoon pop-up showers, but confidence in occurrence as well as
specifics about timing and location is still too low to warrant
edits to NBM init.
Monday afternoon, PoPs in the 20-30% range reflect another chance of
lower-coverage afternoon showers that may gain some support in the
form of return flow from a mesohigh that gets stuck on the other
side of the Eastern Continental Divide. Rain chances do seem to
have stabilized some for Tuesday and Wednesday, with widespread
30-40% chances beginning Tuesday afternoon. The nature of shower
and storm chances Thursday and beyond will depend on the speed and
intensity of the shortwave when it arrives to our area, though
current guidance continues 25-40% PoPs on Thursday and Friday as
well.
Wednesday is when ensemble members go from well-aligned to
significantly divergent, with cluster analysis suggesting several
sources of uncertainty driving the disagreement, most of which can
be summarized as "what happens to the low once it bowls into
western Kentucky". Notably, while the EPS/GFS ensembles and EPS-
AIFS and GraphCast GFS machine learning ensembles do all have
differences between resolution of individual features and details,
all generally agree on a deepening upper low pushing towards the
eastern US by mid-week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 254 PM EDT Thu Sep 18 2025
VFR conditions continue to persist at the terminals. The scattered
diurnal cumulus field visible in this afternoon`s satellite imagery
is expected to give way to a clearing trend after sunset. This once
again favors the overnight development of radiational fog in the
deeper river valleys, but confidence in fog affecting the terminals
is too low to explicitly mention BR/FG in the 18z TAF package.
The persistence of dry air and the latest HREF probabilities suggest
that the fog should be less pertinent tonight than it was last
night, but if fog-related vsby reductions were to affect a TAF site
overnight, they would most likely happen at KLOZ or KSME. Winds are
generally expected to remain light and variable throughout the TAF
period, with a few gusts between 10 and 15 knots possible early this
afternoon via diurnal mixing.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...GEERTSON
LONG TERM...CAMDEN
AVIATION...MARCUS

NWS JKL Office Area Forecast Discussion