135
FXUS63 KLMK 180535
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
135 AM EDT Thu Jul 18 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Scattered showers and storms continue through this evening, with
    a northwest to southeast drying trend expected tonight behind a
    cold front.

*   Cooler temps and lower dewpoints expected Thursday and Friday.

*   Gradual warm up this weekend with increasing mugginess by early
    next week. Shower and storm chances also return in that
    time frame.

&&

.UPDATE...
Issued at 947 PM EDT Wed Jul 17 2024

At this hour, scattered showers and thunderstorms continue to push
from north to south across central Kentucky and southern Indiana
along and ahead of a cold front which is dropping through the
region. There is still 1000-1500 J/kg of mixed-layer CAPE available
at this hour, and though low- and mid-level lapse rates remain quite
poor, limiting overall development, the mid-level trough axis
sliding through the region has supported an increase in shower/storm
coverage over the past hour or so. Recent HRRR solutions support
this increasing coverage of showers/storms mainly along and south of
I-64 over the next few hours, with cells becoming more numerous as
they approach south central KY. Brief heavy downpours and gusty
winds would be the main hazards associated with showers, in addition
to lightning with any thunderstorms.

As we head through the night, a drier and more stable air mass will
continue to filter into the region from the north, bringing an end to
precipitation chances from north to south. With the front not
expected to clear southern KY until tomorrow morning, lingering
precipitation chances are expected through most of the overnight
hours. Areas of fog continue to look like a good bet tomorrow
morning across the Lake Cumberland region, as low-level moisture
will be slow to scour out. Localized patchy fog will be possible
elsewhere in locations which received substantial amounts of
rainfall today/tonight, though light northerly winds should help to
limit fog extent once the cold front passes through.

Only minor tweaks to the forecast were made, mainly to handle near-
term precipitation trends. Otherwise, the forecast remains on track.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 314 PM EDT Wed Jul 17 2024

Scattered showers and storms are developing across the region as
expected this afternoon. Despite the cloud cover earlier, we have
been able to warm into the low 80s, but being in a pre-frontal
airmass, we still have dewpoints in the low to mid-70s. We`ve been
able to realize instability ranging from 1500-3000 J/kg, with the
greatest thermodynamics across our south. Storms having been firing
across south-central KY this early afternoon, which is where the
higher CAPE values are located along with steeper low level lapse
rates. Shear remains rather weak due to the upper level jet streaks
well to our north, so still expect most storms to be unorganized.
DCAPE is highest to our south, but any stronger cell could lay down
some gusty winds. High PWATs will remain across the region until the
front brings in drier air, so until the front passes through, any
shower or storm will also be capable of torrential rain rates.
Luckily, the current storms this afternoon appear to be progressive
enough to minimize flooding concerns. However, any additional rounds
of heavy showers or storms over the same areas this evening could
result in a localized flood issue.

For tonight, any leftover precip along the front will be getting
push to the southeast as the front slowly passes through. Could
still see some heavy rainers even after sunset with CAPE lingering,
but again the shear will be fairly meager. Drier conditions will be
settling in from northwest to southeast this evening and tonight.
The cold front should be through just about all of our area by 06z,
and entirely post-frontal by daybreak tomorrow.

Tomorrow`s forecast is a great one to see: drier weather, much less
humidity, and cooler temperatures will be in store for us. Northerly
flow behind the front will push out the humid airmass we`ve been
stuck with the last several days, and temperatures will reach the
low 80s, several degrees below normal for mid-July. After having
dewpoints in the 70s, tomorrow`s dewpoints will be in the upper 50s
and low 60s. Clouds will be departing with the cold front, so we
should have more sunshine by the late morning or early afternoon.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 314 PM EDT Wed Jul 17 2024

The cooler/drier post-frontal airmass will continue into Friday with
highs in the lower 80s and lower humidity expected.

By the weekend, the upper level pattern will shift to a baggy trough
over the Plains which will remain in that area through mid week next
week. This will leave southern IN and KY under an active
southwesterly flow.  A sfc boundary from the Gulf state will
gradually lift north toward the lower Ohio Valley this weekend
bringing showers/storms to southern/eastern portions of KY.  By
Mon/Tue time frame the sfc front will lift north through our region
bringing better chances for showers/storms over all of southern
IN/central KY each day especially afternoon/evening hrs.

Temperatures will warm back into the mid to upper 80s for highs
Sat/Sun when there`s less convection around. Then temps drop back
slightly into the middle 80s for highs during the first half of the
work week.  Low temperatures will remain in the 60s for the weekend
and through mid next week.

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 135 AM EDT Thu Jul 18 2024

As the front continues pushing south through the region, rain
showers will come to an end at BWG in the next couple of hours.
Until then, BWG can expect a couple rounds of light to moderate
showers. Winds during the overnight will be light under VFR
ceilings. The ceilings are expected to limit fogging, but some
isolated fogging can`t be ruled out. The rest of the period is
expected to remain dry with northerly winds.

&&

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

&&

$$

UPDATE...CSG
SHORT TERM...CJP
LONG TERM...AMS
AVIATION...KDW