Stephensburg, Kentucky Weather Forecast Discussion

384
FXUS63 KLMK 260910
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
510 AM EDT Fri Sep 26 2025
...Forecast Update...
.KEY MESSAGES...
*  Areas of Dense Fog developing this morning, especially near
   bodies of water and recent heavy rainfall. Use caution for
   the morning commute.
*  Mostly dry with warming temperatures expected this weekend.
*  Uncertainty for next week, but the current forecast is for
   mostly dry and warm.
&&
.UPDATE...
Issued at 509 AM EDT Fri Sep 26 2025
Went ahead and ramped up the messaging for dense fog this morning as
obs and webcams are trending downward over a larger area. A Dense
Fog Advisory has been lifted along an axis that is a mixture of the
heavy rainfall axis yesterday, and the dividing line for areas that
did not clear out as fast yesterday afternoon, and therefore didn`t
mix the BL very well. NW portions of the CWA were the first to clear
out and are also a bit deeper into the dry air advection. Meanwhile,
our far SE is just now clearing the clouds. So, may need to do some
tweaking and expanding through the morning, but overall the area in
the current headline is seeing the most widespread fog, while the
other areas are more patchy in nature and handled with SPS. Product
goes til 14z, and we can re-evaluate mid morning.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 253 AM EDT Fri Sep 26 2025
Overall a much quieter night than the past several, however this
quiet pattern will lend to a different forecast hazard through the
pre-dawn hours into sunrise. Several obs have inconsistently bounced
around between 1/4SM up to 5SM through the the first part of the
overnight, however starting to see a bit more consistency in obs
below 2 SM. In other words, conditions appear to be steadily
deteriorating from a fog standpoint, especially near the river
valleys. Current thinking is that we may end up needing a Dense Fog
Advisory before the morning is over. Not quite there yet as we don`t
have widespread 1/4SM on obs or on area webcams just yet. Thinking
the most likely area will be in a half moon around the
eastern/southern portions of the CWA. It is a pretty good type of
setup for dense fog where you`ve had recent heavy rainfall, followed
by a mostly cloudy day that limits mixing, then late clearing in
time for good radiational cooling. We`ve checked all those boxes,
and the only limiting factor has been some dry advection in from the
NW. At the moment, this is why it feels likely we won`t need a
headline up in those area. Will continue to monitor, and be quick to
pull the trigger if obs continue to deteriorate.
Otherwise, look for a quiet day into tonight for all but our far SE
Lake Cumberland region. Here, the upper trough axis closes off into
a weak upper low, and may have enough lingering moisture/triggering
for an isolated shower or storm around peak heating. Will continue
to carry a 20 pop down there with everyone else dry. Highs today
reach into the upper 70s to around 80. Lows tonight look to dip into
the low and mid 50s for most, and will likely have another
opportunity for at least some river valley fog, if not more.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 253 AM EDT Fri Sep 26 2025
Saturday - Monday...
Weak upper closed low will wobble/meander just south/southeast of
our area through the weekend. Meanwhile, upper ridging will steadily
build in from the central CONUS to the Mississippi River Valley,
extending influence into our area. This feature will act to keep us
dry and trend us increasingly warm. The one exception to dry will be
a slight chance of a diurnal shower around the Lake Cumberland
region either afternoon/evening. Highs on Saturday will trend
slightly above normal to the upper 70s and low 80s, then values warm
a bit more for Sunday and Monday more solidly into the low 80s. Look
for pleasant overnight lows in the 55 to 60 degree range.
Tuesday - Thursday...
Confidence will remain low for now with respect to the early/mid
week time frame thanks to some interesting tropical activity. Focus
will be on a likely pair of tropical systems, one of which has a
good shot to move into the Carolinas before heading toward the
central Appalachians. This feature would interact with, and likely
absorb, whatever is left of our weak upper low. The end result could
be rain chances associated with the decaying former tropical cyclone,
but too many scenarios and complexities associated with this
pattern than to say much more than some low end rain chances. In
addition, a tropical system approaching from the SE can sometimes
encounter a downslope drying component with low level jetting
perpendicular to the Appalachians. This dry effect, combined with an
already dry upper ridge in place could gobble up a good amount of
the moisture. For now, the forecast will remain optimistically dry
(outside of 20% chances for our eastern CWA border) with highs in
the upper 70s and low 80s.
Worth noting that another scenario is that the more western tropical
system will interact, possibly a Fujiwara dance, with its eastern
counterpart, and stay out to sea.
&&
.AVIATION /06Z TAFS THROUGH 12Z SATURDAY/...
Issued at 132 AM EDT Fri Sep 26 2025
Quiet night expected with mostly clear skies and light or calm
winds. The big issue will be whether fog develops, and how dense it
will become. Looking at afternoon crossover Ts for BWG/LEX/RGA, it
would suggest that some pretty impactful (possibly dense) fog is
likely in the pre-dawn hours through sunrise. As a result, hit the
fog mention a little harder with this issuance.
Fog clears mid morning on Friday with mostly sunny skies and a light
NNE wind taking hold. Looks like there could be a few cu around 5-6
k feet in the afternoon.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Dense Fog Advisory until 10 AM EDT /9 AM CDT/ this morning for
     KYZ031>043-045>049-054-055-061>065-070>076.
IN...Dense Fog Advisory until 10 AM EDT this morning for INZ079.
&&
$$
UPDATE...BJS
SHORT TERM...BJS
LONG TERM...BJS
AVIATION...BJS

NWS LMK Office Area Forecast Discussion