518
FXUS61 KILN 181922
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
322 PM EDT Fri Apr 18 2025

.SYNOPSIS...
Showers and thunderstorms will develop across the area
tonight and continue through the day on Saturday as a cold front
moves into the Ohio Valley. Temperatures remain above average through the
weekend and through much of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A cold front pushes into the area overnight, though its progress
slows down considerably as it reaches the CWA thanks to blocking high
pressure located over the Atlantic Coast stretching into the
Appalachians.

Showers and thunderstorms will be forced ahead and
along this boundary, though the overnight arrival will have allowed us
to lose our most robust pool of instability, so not expecting too
much in terms of severe, despite a 50-60 knot LLJ cranking into the
region. Worth mentioning the conditional severe in that if we do get
a storm that is able to tap into some elevated instability, strong to
damaging wind gusts and possible hail would be biggest threat with
downward momentum transfer. Low level helicity values in our far
northwest also indicate a non- zero (though very low) tornadic
threat.

&&

.SHORT TERM /EARLY SATURDAY THROUGH SATURDAY NIGHT/...
The front continues to slowly move through the CWA on Saturday with
showers and thunderstorms being forced along and out in front of it.
Similar to the overnight, conditional severe threat remains in place,
with the 50-60 kt LLJ continuing to move through the area. With the
arrival of daytime, some marginal instability is able to build in
(along with an enhanced plume of moisture), so any storms that tap
into this again would have the potential to bring strong to damaging
winds down to the surface, with hail a possibility. The helicity
values on Saturday daytime are not quite as robust, so TOR threat is
minimal.

In addition to the conditional severe threat, we`ll also be watching
heavy rainfall. PWATs of 1.5 inches, marginal CAPE values, and
column RH values around 75-90% all suggest efficient rainfall rates.
These factors combined with the southwest to northeast storm
progress/training storms may introduce localized flooding during
early morning to late morning hours on Saturday.

Heaviest rainfall tapers off by late morning, though off and on
showers continue into Saturday afternoon. With the front stretched
out across the region, highs reach the upper 60s in our northwest,
upper 70s (low 80s??) in south central OH/ northern KY. Dew points
soar to the low 60s.

Off and on rain showers continue into the overnight, though
instability is cut off by the forward progression of the frontal
boundary, so pulled thunder out of most areas in the grids. Overnight
lows fall to the upper 40s along and north of I-70 with upper 50s
along the Ohio River.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
H5 ridge builds across the eastern CONUS on Sunday, with a
negatively tilted trough and associated surface low moving into the
Midwest region. Warm front will begin to lift northward through the
ILN fa, so a temperature gradient will likely be present through our
CWA on Sunday. Highs could reach the 80 degree mark in northern KY,
whereas locations north of I-70 may struggle to reach 60. Some rain
is possible with the associated isentropic lift, but the best
forcing will arrive on Monday with the cold front. Instability does
build into the region on Monday, but models are showing very
marginal instability levels. Thus, thunderstorms are possible, but
severe potential may be limited.

Quasi-zonal H5 flow develops on Tuesday. We will be observing higher
heights with this flow regime, which in turn, will result in a
warmer air mass pushing into the Midwest region. Thus, temperatures
are likely to trend above seasonal normals through the remainder of
the work week. High pressure will offer drier conditions Tuesday and
Wednesday. Thursday may end up trending dry as well, but by late
week, a shortwave trough will ripple through the Ohio Valley,
resulting in increased PoPs on Friday.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
Afternoon southwesterly winds remain sustained around 15 knots,
gusting to 35 knots at times this afternoon, particularly for
northern TAF sites (DAY CMH LCK). Winds decrease slightly after
sunset, but still remain gusty (sustained 12, gust to 20kt or so).
VFR conditions continue through the afternoon and into the evening
with high clouds overspreading the region.

Once we get into the overnight, things get messy. A boundary will
move east into the region and lay out across the area. Depending on
how far southeast it meanders will impact rain/TSRA/cloud decks
etc.... For now, have tried to time out overnight/early morning
showers and -TSRA by using PROB30 groups. There will be periods of
rain showers and thunder moving from southwest to the northeast
starting during the late overnight hours and continuing into Saturday
daytime. Have a mix of MVFR and low end VFR CIGs, though confidence
on timing with these is low right now.

While there may be some mechanical turbulence this afternoon, true
LLWS is reintroduced to all TAF sites around midnight or shortly
after and will taper off around sunrise Saturday. Southwesterly flow
continues on Saturday, sustained around 12 knots, gusting to 20
knots, slowly veering to westerly.

OUTLOOK...MVFR/IFR conditions possible along with a chance of
thunderstorms into Saturday night. Some MVFR CIGs are possible early
Sunday.

&&

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

&&

$$

SYNOPSIS...CA
NEAR TERM...CA
SHORT TERM...CA
LONG TERM...Clark
AVIATION...CA