111
FXUS63 KLMK 222352
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
752 PM EDT Fri Aug 22 2025

...Updated Aviation Discussion...

.KEY MESSAGES...

* Frontal boundary to pass through the region on Saturday
  afternoon/evening with scattered showers/storms possible.

* Pattern change aloft will lead to well below normal temperatures
  to close out August.  Overnight lows are likely to drop into the
  upper 40s in spots.  Record low temperatures over in the Bluegrass
  region could be tied/broken Tuesday/Wednesday/Thursday morning.

&&

.SHORT TERM /THROUGH SATURDAY NIGHT/...
Issued at 244 PM EDT Fri Aug 22 2025

On the synoptic scale, a large upper level ridge was analyzed over
the four corners region with the ridge axis extending northeast from
there into the upper Midwest and upper Ohio Valley.  A baggy trough
was located over the southeastern US on the back side of departing
tropical cyclone Erin.  A strong closed low was over Manitoba
working eastward.

Closer to home, morning clouds finally have given way to partly to
mostly sunny skies as low-level surface heating has helped erode the
nocturnal temperature inversion up near 850 hPa.  This has delayed
insolation across the region and temperatures ranged from the mid
70s to the lower 80s.  For the remainder of the afternoon, look for
partly to mostly sunny skies with afternoon highs topping out in the
upper 70s to the lower 80s.  A few upper 80s will be possible down
across portions of south-central KY near the Columbia area.
Temperatures this evening will cool back into the low-mid 70s,
though portions of southern IN could cool into the upper 60s by
sunset.

For the overnight period, upper ridge axis will retreat westward
while the closed low over Manitoba works eastward toward Ontario and
the Great Lakes.  Our skies should remain generally clear with
perhaps a few scattered clouds around.  Light winds and moisture
trapped below an increasing temperature inversion probably will lead
to a mix of low stratus and/or patchy fog developing toward morning.
Overnight lows will drop into the 62 to 67 degree range.

For Saturday and Saturday night, closed upper low over Manitoba will
continue to move eastward toward Ontario and the Great Lakes while
deepening.  Southward extending upper trough axis will barrel
through the Midwest driving a cold front into the Ohio Valley in the
afternoon/evening.  Winds will generally be southwesterly during the
day on Saturday resulting in some moisture and warm advection.
Scattered showers and a few storms will be possible, mainly along
and SE of a line from Bowling Green to Lexington.  These storms will
diminish with the loss of heating Saturday night.  Depending on the
extent of morning status, temperatures on Saturday should warm into
the mid-upper 80s.  However, if extensive stratus develops and
doesn`t mix out quick, highs may only reach the lower 80s.  Lows
Saturday night will cool back into the lower-middle 60s.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 244 PM EDT Fri Aug 22 2025

Sunday through Wednesday Night...

Surface cold front should be exiting the region by Sunday morning.
Behind this front, substantial upper troughing will be noted across
the eastern US for the first half of the week with upstream riding
across the western US.  A persistent influx of cooler air will be
ushered into the region and temperatures will be running some 12-18
degrees below normal for late August especially in the Monday
through Wednesday time frame.  In fact, temperatures during this
period will feel more like mid-late September than late August.

Highs on Sunday look to warm into the 80-85 degree range with lows
dipping into the middle 50s.  Highs on Monday and Tuesday will warm
into the middle 70s, though a few spots south of the Cumberland
Parkway may touch 80 each afternoon.  Very cool temperatures are
expected Monday and Tuesday nights with lows ranging from the upper
40s to the lower 50s.  It is possible that we may be able to
tie/break low temps over in the Frankfort/Lexington area those
mornings.  Highs on Wednesday should moderate some with reading
warming into the 75-80 degree range.  Lows Wednesday night will drop
back into the upper 40s/lower 50s.  Record lows could be tied/broken
again during this period out across the Bluegrass region.

Thursday through Friday...

Broad troughing aloft looks to continue across the eastern US
through the end of the week, though the upper trough axis looks to
shift a little eastward with time.  We`ll have to watch the Thursday
night and early Friday timeframe for a shortwave trough axis that
may bring a few showers to the region.  For now, the blend is dry
through here.  Temperatures will moderate a bit through the period
with highs in the upper 70s to near 80 both day with overnight lows
in the mid-upper 50s.

&&

.AVIATION /00Z TAFS THROUGH 06Z SUNDAY/...
Issued at 751 PM EDT Fri Aug 22 2025

Surface high pressure with some upper ridging will keep skies clear
and winds light overnight. This will lead to strong radiative
cooling and falling temperatures that will lead to fog development.
Current guidance is showing a fairly strong fog signal, but there
could be additional stratus develop in some areas. Either way,
restrictions are expected later tonight into tomorrow morning.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.

&&

$$

SHORT TERM...MJ
LONG TERM...MJ
AVIATION...KDW