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674
FXUS61 KILN 200642
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
242 AM EDT Thu Jun 20 2024

.SYNOPSIS...
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Hot and humid conditions will continue through Sunday until a
cold front moves through the region, bringing brief relief from
the heat. Slightly cooler air settles in Monday before warmer
and more humid air quickly returns by midweek once again.
Although a stray shower or storm cannot be ruled out just about
any day through Sunday, the most widespread chances for storms
through the next week look to be Sunday and next Wednesday.
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&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Mainly tranquil conditions reside locally this morning amidst a
warm, muggy, and stagnant airmass that remains entrenched across
the region. Temps will bottom out generally in the lower 70s by
daybreak before rebounding into the lower to mid 90s by late
afternoon once again.

There are a few indications for /slightly/ drier air to
develop/mix within the BL this afternoon, which could yield
dewpoints that are on the order of 2-4 degrees /lower/ than was
the case during peak heating Wednesday. The flip side of the
coin, however, will be actual air temps that will likely run 2-4
degrees /warmer/ than was the case Wednesday. So the end result
is going to be approximately the same -- heat index values in
the upper 90s to briefly around 100 degrees at times. It
certainly won`t feel any cooler or any different than the past
few days, despite a slightly warmer/less humid afternoon than
has been the case throughout the week thus far.

The other item of interest will be the potential for a few ISO
stray SHRA/TSRA to develop this afternoon. This may
particularly be the case within a N-S oriented axis very near,
and just to the E, of the I-75 corridor where a subtle LL
convergent axis develops, helping pool slightly better moisture
in these areas. This is already evident on nighttime
microphysics with the development of some clouds in these areas.
This convergent axis is courtesy of a weak/small LL high
positioned to the SW of the ILN FA, with another one to the E
across the mid-Atlantic, allowing for very light W/NW BL flow
across wrn parts of the area and very light E/SE BL flow across
ern parts of the area. This may be just enough to focus some
slightly higher dewpoints within a narrow axis, supporting the
potential for some ISO convection near/just E of I-75.
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&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
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More of the same is on tap tonight -- warm and muggy conditions
with lows bottoming out in the lower 70s. Friday will be a near
carbon copy of today`s weather, except perhaps another few
degrees warmer (but with dewpoints a few degrees lower).
Anticipate that highs will top out in the mid 90s Friday, with
afternoon dewpoints generally in the mid to upper 60s, yielding
heat index values just a 2-3 degrees above actual air temps.

Although a very ISO SHRA/TSRA cannot be ruled out Friday,
especially in central OH, most areas again remain dry.
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&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
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The 700H- 500H ridge continues to retrograde back through the
Tennessee Valley region, with the ILN CWA comfortably seated near
the center of the high. Consequentially, Saturday will be one of the
hottest days of the ongoing heatwave, with high temperatures in the
upper 90s and dew points in the upper 60s/low 70s. This results in
"feels like" temperatures around 100F for most areas but especially
in our metro areas, continuing to remain in advisory level criteria.
With that being said, Saturday marks day 6 of the prolonged heat
(Heat Advisory products came out on Monday, 6/17). Consequentially,
the Heat Risk category remains "Extreme" for much of our area. Visit
wpc.ncep.noaa/gov/heatrisk/ for details on the Extreme Heat Risk
category. Unfortunately, not much relief Saturday night into Sunday
with overnight lows only falling to the upper 70s.

Sunday, a shortwave moving through the Great Lakes region will bring
a cold front through our area Sunday afternoon and evening. Showers
and storms will be forced out ahead of the frontal boundary. Right
now, CSU severe highlights all of the region with a low end severe
probability. This is likely due to the ample CAPE (and DCAPE) that
will be in place with some shear aloft, given the 850mb jet. Will be
something to keep an eye on as we get nearer. Highs on Sunday reach
the low 90s with overnight lows into Monday fall to the upper 60s.

In the relatively cooler post-frontal air, Monday will be a slight
respite from the heat, with highs in the upper 80s. While this
doesn`t sound like much, we might actually notice a difference,
given the surge of dry air that moves into the region behind the
front. In fact, dew points drop from the low 70s into the upper 50s.
Overnight low temperatures in the mid 60s.

This is all short lived, as we quickly rebound with return southerly
flow on Tuesday ahead of the next system poised to move into the
region and highs bounce back into the low 90s. We`ll continue to
keep an eye on this mid week wave as it looks to impact the region
sometime around Wed/Thur next week. Still a bit far out for details,
but ECMWF, CMC, and GFS ensembles all hone in on a notable negative
height anomaly moving through the Great Lakes region mid to end of
next week.
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&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
Aside from an axis of a FEW/SCT VFR Cu percolating about
KCVG/KLUK/KDAY, skies have trended mostly clear, allowing for
patchy BR/FG to begin to develop in a few spots. The BR will
likely be most pronounced in river valleys and in sporadic areas
where appreciable rainfall has occurred over the past several
days. Have included some brief IFR VSBYs at both KLUK/KILN to
account for this potential, especially with the light/calm winds
and remnant muggy/stagnant airmass in place.

Diurnally-driven expansion of the Cu field is expected by/past
16z, with SCT conditions expected to prevail for most of the
area during the latter half of the daytime. Some BKN Cu may
develop in pockets, especially for KDAY/KILN. Cannot rule out a
stray afternoon/early evening SHRA/TSRA for nrn sites, including
KILN, but coverage should remain fairly limited.

Light southerly flow will occasionally be more VRB, especially
during the daytime, with non-storm-related winds staying
generally around 5kts or less through the period.

OUTLOOK...Thunderstorms possible on Sunday.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Heat Advisory until 8 PM EDT Saturday for OHZ026-034-035-
     042>046-051>056-060>065-070>074-077>082-088.
KY...Heat Advisory until 8 PM EDT Saturday for KYZ089>100.
IN...Heat Advisory until 8 PM EDT Saturday for INZ050-058-059-066-
     073>075-080.

&&

$$
SYNOPSIS...KC
NEAR TERM...KC
SHORT TERM...KC
LONG TERM...CA
AVIATION...KC