-- Discussion containing changed information from previous version are highlighted. --
277
FXUS63 KLMK 181740
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
140 PM EDT Wed Sep 18 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*  Mostly dry with just a few isolated showers, mainly along and
   east of I-75 later today.

*  Mainly dry and hot weather Thursday through Sunday with highs
   each day near 90 degrees.

&&

.UPDATE...
Issued at 1051 AM EDT Wed Sep 18 2024

This morning, a mix of sun and clouds is being observed across the
region as sky cover is quite variable across the FA at this hour.
Patchy areas of fog have largely dissipated over the last hour, with
moisture lifting into a low stratus layer. As we head through the
late morning and into the afternoon hours, boundary layer moisture
should mix up into a stratocu deck, especially east of I-65. West of
I-65, a general clearing trend is expected later this afternoon as
the mid-level low centered over the southern Appalachians begins to
pivot away from the region. While an isolated sprinkle or light rain
shower is still possible this afternoon and evening, preliminary 12Z
guidance is less bullish on coverage, keeping most of the showers in
eastern KY. Temperatures remain a bit uncertain this afternoon, as
less cloud cover will allow temps to rise into the mid-to-upper 80s,
while greater cloud cover will hold values in the upper 70s and
lower 80s.

At this hour, the forecast is on track. Have blended some hi-res
temp guidance which is handling the morning sky cover better than
global inputs. Updated products will be sent shortly.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 251 AM EDT Wed Sep 18 2024

We will remain under the influence of a nearly stationary upper low
currently centered over the southeastern US for today. We`ve seen a
little more low-level moisture advect in from the Atlantic thanks to
the cyclonic circulation associated with this system. Current
satellite imagery shows some low stratus across south central KY
close to the KY/TN border extending eastward into the Lake
Cumberland region. This low-level moisture could result in some
lingering clouds this morning and scattered afternoon Cu to develop.
We still have a very small chance of a few isolated showers forming
later today across our east, with the best chances (10-20%) along
and east of the I-75 corridor.

Temperatures will remain a challenge for this afternoon due to
uncertainty with cloud cover. If we stay mostly to partly sunny
highs could warm into the mid 80s but where clouds remain the
longest, mainly towards the east, highs may just make it into the
low 80s.

Overnight the upper low will finally start to slowly work east-
northeast towards the Chesapeake Bay as sfc high and upper ridging
work in from the west. Skies will clear out and winds will remain
light overnight. We could see patchy fog develop towards morning.
Lows will generally be in the low 60s with a few upper 50s across
our far east and mid 60s for our more urban areas.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 251 AM EDT Wed Sep 18 2024

Dry and hot weather will take hold for the weekend as an upper high
over Texas will be the main feature of interest. Ridge axis will
extend NE to Lake Michigan on Thursday, with heights over the Ohio
Valley rising slightly as the ridge axis takes a more west-to-east
orientation. Unseasonable warmth will prevail through the period,
but Fri-Sat will be the hottest days with H8 temps building to 20C,
supporting widespread highs in the lower 90s. Lack of deep return
flow will keep convection and heat indices in check.  In fact, with
sfc dewpoints near 60F, heat index values may even be a degree or
two lower than the actual air temperature. Min temps will trend a
bit warmer through the weekend, but most should be in the 60s each
morning.

Confidence does start to decrease on Sunday as some of the ensemble
members start to drop a sfc cold front into the Ohio Valley, and the
operational GFS is even spitting out some precip. Most ensemble
members leave us high and dry, so will not include POPs in the
forecast at this time.

Rain chances do ramp up early next week as consensus increases that
a front will be in play at that time. Still some uncertainty in the
timing as run-to-run consistency hasn`t been established yet, so
we`ll keep precip chances in the 20-30% range, and temps will
continue to run above climo, but not by as much as this weekend.

&&

.AVIATION /18Z TAFS THROUGH 00Z FRIDAY/...
-- Changed Discussion --
Issued at 140 PM EDT Wed Sep 18 2024

A broken stratocu deck is present across the area this afternoon as
left over tropical moisture lingers over the region. These low
clouds should gradually dissipate later this evening, although a SCT
4-5 kft cloud layer may hold on for an extra few hours at LEX and
RGA. Light N/NE winds are expected until around sunset this evening,
with winds going light and variable for the overnight hours. There
is a fairly strong signal for fog early tomorrow morning, especially
at BWG and RGA. The main uncertainty is whether or not the low-mid
cloud layer hangs around overnight, which would reduce fog
potential. Any fog which does form should dissipate by 13-14Z
Thursday, with VFR conditions and light north winds expected through
the end of the current forecast period.
-- End Changed Discussion --

&&

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

&&

$$

UPDATE...CSG
SHORT TERM...BTN
LONG TERM...RAS
AVIATION...CSG