471
FXUS61 KILN 051723
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
123 PM EDT Sun May 5 2024

.SYNOPSIS...
A warm and moist airmass will remain in place across the region
into the middle part of next week, leading to occasional
periods of showers and thunderstorms into Thursday. Slightly
cooler and drier air will return by the end of the week,
although rain chances may persist at times into next weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Subtle adjustments were made to the ongoing fcst this morning,
mainly to sky cover/temps as an axis of clearing has worked its
way into the Miami Valley and Tri-State regions, allowing for
temps to jump a bit quicker than the cloudier surroundings.
Nevertheless, the main expectations for today remain unchanged
as a few ISO/SCT SHRA/TSRA are expected to develop by mid
afternoon, particularly near/E of I-71 into central OH, as a
weak front moves through the area. There is some hint of
stronger deep layer shear and instability overlapping near the
Columbus metro in the afternoon, as represented by SPC marginal
risk, so an isolated strong wind gust cannot be ruled out.
Forecast highs are generally in the upper 70s to lower 80s
(especially in N KY).

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
An area of high pressure will be moving across the Great Lakes on
Sunday night while zonal upper level flow persists. South of the
high, a cold front is expected to be sinking southward into the Ohio
Valley. The frontal boundary is forecast to reach near the Ohio
River before stalling late overnight into the early morning hours.
Rain chances should remain fairly low overnight and confined to the
warm sector south of the cold front. Winds shift to the north behind
the front. Lows drop into the 50s north of the front while remaining
the the lower 60s south of the front.

The surface high remains to the north of the Ohio Valley on Monday
which helps keep the stalled front near or just north of the Ohio
River through the day. A fairly strong dew point gradient and small
temperature gradient should be observed by the afternoon. Areas
south of the front should have dew points rising into the 60s while
areas north of the boundary have forecast dew points remaining in
the 50s. Shower and thunderstorm chances remain mostly confined to
areas in southern Ohio and northern Kentucky in the afternoon where
some instability may develop overlapping the best moisture. Very
isolated locally heavy downpours in slowly moving shower/storms
could develop.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
Broad upper level troughing over the western two thirds of the
CONUS will shift slowly east through mid week, keeping the Ohio
Valley in persistent west to southwest flow aloft. This will allow
for a series of embedded mid level short waves to move through the
region Tuesday through Thursday. At the surface, a frontal boundary
along the Ohio River will lift north across the area through the day
on Tuesday with afternoon highs climbing into the upper 70s to lower
80s. This will combine with surface dewpoints in the mid 60s to
produce surface based capes into the 1500-2000 J/kg range. This will
result in fairly widespread shower and thunderstorm development
Tuesday into Tuesday evening and with strong deep layer shear
develop through the day, some severe storms can be expected.

A trailing cold front will push southeast across our area Tuesday
night before stalling out heading into Wednesday morning. There is
then some uncertainty as to how far back to the north the front will
lift through the day on Wednesday ahead of an approaching low
pressure system. Along and south of the boundary, good instability
will develop with fairly widespread showers and thunderstorms
possible once again. With strong deep layer shear persisting and the
approach of a surface low, severe storms will again be possible.
Highs on Wednesday will be in the upper 70s to lower 80s.

A cold front will then push off to our southeast later Wednesday
night into Thursday, leading to lower pcpn chances and slightly
cooler temperatures. Highs on Thursday will be in the mid to upper
70s. Additional short wave energy dropping down across the Great
Lakes will help deepen the trough over the Great Lakes and Ohio
Valley Friday through Sunday. This will keep us in a cooler airmass
with daytime highs in the 60s to lower 70s. This will also keep some
lingering lower end chances for showers and a few thunderstorms
through the weekend.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A mix of MVFR/VFR diurnally-enhanced Cu has expanded with
daytime heating, but expect that CIGs should gradually
transition to more VFR within the first hour or so of the TAF
period (if they haven`t already done so).

For early in the TAF period, still expecting a few SHRA/TSRA to
develop near KCMH/KLCK through about 22z or so before the
activity pushes further to the E. Confidence is somewhat low
regarding coverage, but there seems to be enough of a signal for
a few SHRA/TSRA around central OH to add a TEMPO. Elsewhere, a
stray SHRA/TSRA cannot be completely ruled out at KILN, but
would expect that activity should focus a bit further E of the
site.

Conditions will trend dry area-wide by/past 00z before more
widespread SHRA/TSRA moves in from the SW past 09z, impacting
KCVG/KLUK by daybreak. But until we get to that, some BR/FG will
be possible once again tonight, especially as mainly skies
(except for some cirrus) should evolve from 00z through about
09z. With ample rainfall in recent days and mostly clear skies
and relatively light/variable/calm winds, the potential for
some patchy fog/VSBY reductions exists, especially for
KILN/KCVG/KLUK.

MVFR CIGs and VSBYs coincident with pcpn are expected to spread
in from the SW past daybreak. A few uncertainties in just how
far N the activity spreads, with a sharp cutoff likely near
KCMH/KLCK by the end of the period. Fairly widespread pcpn is
expected further S toward KILN/KCVG/KLUK between 12z-18z.

Light WNW winds will become more northerly (at ~3-5kts) around
00z before going easterly by daybreak and eventually out of the
ESE by Monday afternoon. Winds should remain 10kts or less
through the period.

OUTLOOK...Thunderstorms are possible at times each day through
Thursday. MVFR conditions are possible Tuesday morning.

&&

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

&&

$$
SYNOPSIS...Campbell
NEAR TERM...KC
SHORT TERM...Campbell
LONG TERM...JGL
AVIATION...KC