442
FXUS63 KLMK 290518
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
118 AM EDT Sat Jun 29 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*   Very warm and muggy tonight with lows in the 70s.

*   Storm chances increase Saturday into early Sunday. Locally heavy
    rain and gusty winds will be the main threats. Above normal
    temperatures return by early/mid next week.

*   Another period of unsettled weather returns to the region by
    late Wednesday and Thursday.

&&

.UPDATE...
Issued at 117 AM EDT Sat Jun 29 2024

Even isolated showers have struggled to develop today, and the radar
remains quiet at this hour. The atmosphere is already fairly stable
upstream across portions eastern IA, MO, and IL. It does not appear
significant convective development will take place and survive the
trip to southern IN or central KY. Expect a warm, dry night with
mostly cloudy skies and a light southerly wind. Temperatures have
dropped into the low to mid 80s in most places as of this writing
and will continue to slowly fall into the 70s overnight.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 319 PM EDT Fri Jun 28 2024

Afternoon satellite and obs show mostly sunny skies across the
region.  Diurnal Cu field is in full swing across much of the area
with the greatest concentration across southern KY.  Temperatures as
of mid-afternoon were in the mid-upper 80s in many areas, though a
few spots had already hit 90.  Dewpoints were in the upper 60s to
the lower 70s resulting in heat indices in the low-mid 90s, though
a few spots near the KY/TN border had heat index readings near 100.

For the remainder of the afternoon, not much change is expected in
the overall weather pattern.  Mostly sunny skies are expected with
highs topping out in the upper 80s and lower 90s.  Latest model
soundings still show a bit of a cap around 700-650mb and that should
hold across southern IN and much of the northern half of Kentucky.
The cap may be slightly weaker across southern KY where a few
isolated showers/storms could develop later this afternoon/evening.
As we move towards sunset, temps will fall back into the low-mid 80s
and winds will slacken and shift to the southeast.

For the overnight period, a warm night is expected across the region
with some mid-high level cloudiness moving in from the northwest.
Overnight lows will only drop into the mid-upper 70s.  Towards dawn,
we may see a few showers/storms move into our northern CWA as
ongoing convection northwest of here will drift southeast and
continue to wane.

For Saturday, upper level shortwave trough axis will swing through
the Great Lakes on its way to New England.  An associated surface
cold front will slowly drop southward towards the Ohio Valley during
the daytime hours.  Main question about temperatures tomorrow will
be the effects of possible cloud cover that may be in the region. It
looks like we`ll have some cloud cover to deal with and quite a bit
of low-level moisture streaming into the region.  Highs on the day
will likely top out in the upper 80s to the lower 90s once again.
Given those temps and dewpoints in the low-mid 70s will result in
heat index values warming into the upper 90s and lower 100s once
again.

Instability will be on the increase throughout the afternoon and we
should see MLCAPE values rise into the 1000-1500 J/kg range, perhaps
with locally higher bubbles of instability.  PWATs will be above 2
inches in most areas, but model soundings continue to show very
marginal deep layer shear for supporting organized convection.  We
should see some scattered showers and storms develop during the
afternoon in advance of the front.  Given the higher instability/low
shear setup along with plenty of moisture, wet microbursts and
torrential rainfall will be the main hazards with any storms.  Given
the slow storm motions expected, some localized flooding may occur
in areas that see a slow moving storm go by.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 319 PM EDT Fri Jun 28 2024

Saturday night, a cold front will get pushed southeast through
Illinois and Indiana before reaching southern Indiana and central
Kentucky later in the night. Now that this period is in range of
some CAM guidance, believe the first half of the night will remain
mostly dry, but by the second half of the night, parts of the CWA
could see scattered thunderstorms. Given the time of day, chances of
severe weather will be reduced with a low level inversion in place,
but with over 2,000 J/kg or MLCAPE and 2,500 J/kg of MUCAPE with
added forcing from a cold front, a severe storm or two can`t be
ruled out. One limiting factor will be weak deep layer shear (0-6
km) around 20-25 knots. Small hail could be realized, but the
greater threat will be some gusty winds if the nearly 1,200 J/kg of
DCAPE can punch through the inversion. The front will divide low
temperatures as areas behind the front in southern Indiana are
expected to drop into the upper 60s to near 70 while areas south
will only see the low to mid 70s.

On Sunday, as the front get pushed through the CWA, cold air
advection will do little to limit temperatures because upper ridging
and surface high pressure will bring clear sunny skies over the
Lower Ohio Valley. This will help to lift temperatures into the mid
to upper 80s with a few 90s possible. The CAA is expected to knock
Monday`s highs lower than Sunday`s, but as the center of the surface
high gets pushed across the Great Lakes, return flow will begin
lifting temperatures back into the 90s by Tuesday. 90s are expected
to remain through the end of the work week.

By Wednesday night to Thursday an approaching cold front/upper
trough moving across the Midwest will try to displace the upper
ridge over the Ohio Valley, but with upper high pressure dominating
over the South, the ridge will likely flatten as the front lays out
over the high to the south. This will place the front over parts of
the Lower Ohio Valley which would bring additional chances for
showers and thunderstorms through the end of the week.

&&

.AVIATION /06Z TAFS THROUGH 12Z SUNDAY/...
Issued at 117 AM EDT Sat Jun 29 2024

Will stick with prevailing VFR conditions for this TAF period.
Spotty SHRA/TSRA are possible just about any time, but the best
chances will come with diurnal destabilization this afternoon and
evening ahead of an approaching cold front and upper level wave.
Even then, coverage should be scattered and will keep rain chances
at PROB30 at this time.

&&

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

&&

$$

UPDATE...EBW
SHORT TERM...MJ
LONG TERM...KDW
AVIATION...13