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066
FXUS61 KILN 071806
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
206 PM EDT Tue May 7 2024

.SYNOPSIS...
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Several rounds of showers and storms are expected through
Thursday amidst a continued warm and humid pattern. Afterwards,
cooler and slightly drier conditions are expected, though shower
chances can not be ruled out through the weekend.
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&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Still looking to see how the airmass will be modified behind
this initial line of showers and thunderstorms. In the northern
half of CWA, scattered showers have sprung up ahead of the line
and seem to be removing any deeper convection behind it that
would be associated with the original line that lags behind
them. To the south, moderate to strong thunderstorms can be
found along the line, with a short period of stratiform rain
behind it.

Back edge of cloud cover with a following significant area of
clearing is already at the western border of the CWA. This
feature continues the earlier train of thought regarding severe
potential this afternoon.

Previous discussion(s) remain valid:

Parameters of significant shear and instability remain in place
this afternoon for severe weather. This is an all-mode severe
weather threat with damaging winds, large hail, isolated
flooding, and tornados. Tornado parameters per SPC and some AI
forecasts have the entire CWA with a potential of significant
tornados >EF2. The AI enhances a more narrow corridor running
sw-ne through Cincy metro area, curving northward into Dayton
metro area.

As a shortwave is ejected northeast from the southern Plains
into the Ohio Valley, an increase in mid-level flow and backing
low-level winds will be seen in the vertical profile by later
in the afternoon. A surge in warm, humid air should occur just
ahead of the shortwave`s arrival. Forecast soundings continue to
indicate surface CAPEs approaching 2,500 J/kg and effective
shear around 60 knots. In addition, curved hodographs lead to
effective SRH exceeding 200 m^2/s^2.

Without a discrete forcing mechanism this afternoon and evening,
scattered, discrete supercells are likely to develop. High
temperatures will reach into the upper 70s to lower 80s.
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&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
A cold front associated with the shortwave will shift east
across the local forecast area late this evening through
midnight. While hodographs are a bit less curved for this
period, an increase in forcing leads to higher coverage of
thunderstorms, and likely a more organized linear mode. Can`t
rule out some embedded supercells as well based on persistent
bulk shear ahead of the front.

The shortwave will exit to the east late tonight, leading to a
quieter conditions extending into Wednesday. Bright May sunshine
allows high temperatures to exceed 80 degrees across the middle
Ohio Valley. We may see some increase in cloud cover late in
the period as another shortwave begins to eject northeast into
the middle Mississippi Valley.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
A warm frontal boundary will be draped along the Ohio River
early Wednesday evening, extending east from a surface low over
the mid Mississippi Valley. As the low tracks east Wednesday
night, the boundary will begin to lift slowly north across
southern portions of our fa. There remains some uncertainty with
just how far the front will make it, along with the better
instability, but the 00Z models appear to have trended
everything a bit farther to the south. Still, expect to see
showers and thunderstorms overspread the region Wednesday
evening and continue into the night as the surface low moves
through our area.

With very favorable shear and an instability gradient along the
boundary, some severe storms will be possible, with the best
chances mainly along and south of the Ohio River, closer to the
better instability. Damaging wind and large hail will be the
main severe threat, although an isolated tornado will also be
possible. Also, with the potential for training storms along the
boundary and PWs in the 1.5 to 2.0 inch range, there will be a
heavy rain/flood threat, especially across southern portions of
our area Wednesday night. Pcpn will taper off later Wednesday
night into Thursday morning as the low moves off to the east.

An upper level trough will settle in across the Great Lakes and
Ohio Valley heading into the weekend and into early next week.
A series of embedded mid level short waves rotating through the
trough will bring additional chances for showers and a few
thunderstorms each the day, especially Saturday afternoon and
evening. Temperatures will be seasonably cool through the
weekend with highs mostly in the 60s. More seasonable
temperatures will return on Monday with highs in the low to mid
70s.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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Thunderstorms have exited CVG/LUK/DAY and some stratiform rain
will remain over DAY for the next 1/2 hour or so. ILN will see
about an hour`s worth of rain with the bulk of the thunder
occurring before 18:30Z. Less strong storms with a marked
decrease in electrical activity should be working into CMH/LCK
shortly after 19Z. A slightly longer period of widely spaced
convective cells will be followed by an also slightly longer
time with stratiform rain in central Ohio.

With the expected next round of severe weather later today and
this evening, TAFs will need to be amended as needed. Right now,
cells that develop should be scattered, and merge to produce
more widespread activity. Cells that remain on their own have
the best chances to evolve into supercellular storms.

Daytime heating and increasing instability with backing winds
and a bump in low level moisture will promote this second round
of storms. Storms in this later environment will be more
discrete and scattered versus coming in as a line, so VCTS
seemed to be the better forecast for everyone attm. Storms exit
to the south-southeast, first at DAY around 03Z, then by 05Z at
the remaining TAF sites.

Outside of thunderstorm activity, ceilings and visibilities should
remain VFR.

Clouds will begin to decrease after 06Z as the weather system
exits east. Will need to watch for stratus/fog development in
the pre-dawn hours if the clouds clear early.

OUTLOOK...Thunderstorms will be possible late Wednesday into
Wednesday night. MVFR/IFR CIGs are possible Wednesday night into
early Thursday and again on Friday.
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&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.

&&

$$
SYNOPSIS...Franks
NEAR TERM...Franks
SHORT TERM...
LONG TERM...JGL
AVIATION...Franks