086
FXUS61 KILN 160544
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
144 AM EDT Wed Jul 16 2025

.SYNOPSIS...
A frontal boundary will linger across the area through the week and
into the weekend, keeping the threat for daily showers and
thunderstorms across at least parts of the region. A seasonably warm
and humid pattern will also continue for the foreseeable future.
This active pattern with numerous rounds of showers and storms,
especially through the weekend, will bring the potential for heavy
rain and flooding to parts of the area.

&&

.NEAR TERM /THROUGH TODAY/...
Moist ascent continues to overspread the ILN FA with the approach of
a strung-out S/W within the zonal flow aloft. This will allow for at
least ISO SHRA/TSRA potential through daybreak, with an increase in
coverage toward sunrise, particularly the Tri-State into the Miami
Valley, as the best forcing moves in. Steering-layer flow increases
a bit through the morning, meaning that the SHRA/TSRA should be
moving progressively from SW to NE, limiting prolonged heavy rain
over one particular area. However, with PWs again surging above 150%
of seasonal norms, any additional rain in areas that have already
received heavy rain over the past few days may renew localized
flooding concerns as the activity overspreads the area through the
morning.

After the initial round of weakening activity during the morning,
some diurnally-driven intensification and increase in coverage is
expected, particularly near/E of I-75 by early afternoon, with fairly
widespread coverage by late afternoon locally. This coverage should
be greatest near/E of I-75 into NE KY/south-central and central OH by
mid afternoon where the best overlap of forcing and moisture will
still reside. PWs close to 2" will support very efficient rain rates
and torrential downpours, with a much more limited gusty wind
potential.

Spotty amounts of 1-2" are expected through the day today,
particularly for the ern 2/3 of the ILN FA where afternoon activity
will be most widespread. There is a growing concern for a cumulative
effect of heavy rain over parts of the area, especially with the
prospect of a /very/ active short and long term periods late week
through the weekend. This being said, at this juncture, there isn`t
quite enough confidence to issue a Flood Watch for flash flooding
given uncertainties in degree of coverage as well as fairly high
confidence in mainly dry conditions tonight before a resurgence of
storms occurs again on Thursday. At some point, confidence may
increase enough to issue a watch, but in the meantime we will
continue to highlight the potential for heavy rain and localized
flooding in the HWO to maintain awareness.

Very humid conditions will prevail through the near/short term
periods, with overnight lows in the lower 70s and daytime highs in
the mid 80s with dewpoints generally in the lower to mid 70s.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/...
The short term period is going to bring with it a more complex setup
in terms of timing/locations of storms, but the end result is going
to be very similar -- locally heavy rain and isolated flash flooding
due to widespread storms (primarily near/S of I-70) during the
daytime Thursday.

Into tonight, we will see a decrease in SHRA/TSRA activity during the
evening through the overnight before the approach of another weak
S/W from the W brings better moisture and lift back into the area
after daybreak. There is a signal for /very/ high PWs to advect back
into the area ahead of a weak front that will attempt to push S into
the day Thursday. Most of the area will remain S of this boundary,
although there is some latitudinal uncertainty in exactly where this
W-E boundary is going to be positioned by early afternoon. As of
right now, the front should orient itself nearly parallel to, and
close to, the I-70 corridor by noon on Thursday, with substantial
pooling of LL moisture and extreme instby to the S of this boundary.
This, combined with increased forcing from the approaching S/W
amidst an uncapped environment, will provide a focus for several W-E
clusters of TSRA to develop by early afternoon, primarily near/S of
I-70. Coverage of activity should be fairly widespread by mid/late
afternoon near the OH Rvr and points S as it gradually shifts to the
ESE through time.

With extreme instby (SBCAPE >=3000 J/kg) a PWs again near 2", the
concern is there for heavy rain and localized flooding, especially
with steering-layer flow and the boundary being nearly parallel.
This will likely manifest itself in several W-E oriented clusters of
TSRA that will be moving predominantly to the ESE, lending itself to
a greater concern for locally heavy rain Thursday than will be the
case today. This is especially the case as the S/W moves in from the
W by the evening, essentially slowing the ESE progression and
creating the potential for additional TSRA to develop back to the N
(perhaps near/just S of I-70) once again in areas that may have
received heavy rain earlier in the day.

Will continue to monitor trends for possible Flood Watch issuance,
particularly as the favored areas become a bit more clear. It does
seem, at this juncture, that locales N of I-70 may see a bit drier
conditions on Thursday, with most of the afternoon/evening TSRA
activity focused across the srn 2/3 of the ILN FA.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Thunderstorms are likely to be ongoing across portions of the area
Thursday evening and into Thursday night, with the front stretched
out across the central part of the area. The locally heavy rainfall
threat will continue into the overnight as a very subtle shortwave
crosses through the Ohio Valley into Friday morning. The shortwave
may be enough to push the front south closer to the Ohio River,
focusing renewed thunderstorm chances in this region Friday
afternoon and evening. These will likely require effective heating
during the afternoon with the shortwave moving off to the east.

On Saturday, a ridge over the southeast US competes with another
shortwave moving into Midwest. The local area begins to see the
Friday front lift northeastward, opening up the potential for a new
round of deeper moisture and instability by Saturday afternoon. Mean
flow over the region is northwesterly and strengthening, suggesting
the likelihood of more organized convection moving from the Midwest
into the Ohio Valley during the evening. A very similar set up is in
place for Sunday as well with another shortwave moving through the
Midwest. If the moisture is able to return following Saturday`s
convective system, the Ohio Valley may see a second round of severe
weather.

From Monday through midweek, the ridge over the southeast US begins
to build farther north and west into the central Plains. This would
provide a warming trend and sustain a several day period with very
high to extreme CAPE values (3500-5000 J/kg) across the Midwest,
Great Lakes, and Ohio Valley regions. Forcing mechanisms and
steering flow are a bit more uncertain with the ridge building
northward, but confidence is increasing in the development of a
classic "ridge-riding" conceptual model. The jet stream will be
farther north, but with enough wind shear, thunderstorms forming
along a stationary front can organize, moving downwind around the
building ridge. As is always the case with these types of scenarios,
specific details for the local area likely won`t be known until the
pattern is established.
&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Dry conditions will prevail for the start of the TAF period, but
expect some ISO/SCT SHRA to develop near KDAY/KCMH/KLCK within the
first few hours before a larger cluster of SHRA/TSRA moves in from
the SW toward daybreak. The most widespread activity (and potential
for MVFR VSBY) through 15z is expected near KCVG/KLUK, with the
cluster eventually moving to the NE and slowly weakening through the
morning toward KILN.

However, a diurnally-driven increase in both coverage/intensity is
expected into early afternoon, focusing near/E of I-75 by mid
afternoon through early evening. Only had confidence right now to add
an afternoon TEMPO TSRA group for KILN, but certainly one may be
warranted elsewhere as well as the signal for better storm clustering
comes into focus.

Aside from some brief MVFR VSBY at KLUK due to BR through the predawn
hours, VFR conditions will prevail through the period outside of
SHRA/TSRA activity. Abrupt changes in VSBY, wind speed and direction
are all likely with the heaviest pcpn. Coverage of SHRA/TSRA
decreases by 00z and beyond, with only a spotty SHRA possible through
tonight.

Light ESE winds at 5kts or less will go out of the SW at 10-15kts by
the afternoon before decreasing again to 5-10kts after 00z.

OUTLOOK...Thunderstorms are possible each day through Sunday.

&&

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

&&

$$

SYNOPSIS...KC
NEAR TERM...KC
SHORT TERM...KC
LONG TERM...McGinnis
AVIATION...KC