410
FXUS61 KILN 021952
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
352 PM EDT Tue Jul 2 2024

.SYNOPSIS...
Hot and humid conditions are expected on Wednesday along with
increasing chances for showers and thunderstorms as a cold front
approaches from the northwest. This boundary will then remain
in the area on the Fourth of July. Embedded mid level
disturbances will interact with this boundary, resulting in
multiple rounds of showers and thunderstorms. A stronger weather
system is expected to move into the Great Lakes and Ohio region
Friday into Friday night, continuing the threat for showers and
thunderstorms.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Weather remains quiet across the area this afternoon with
temperatures topping out in the upper 80s to lower 90s.

A weak, low-level trough is moving northward on the western
periphery of the surface high pressure to the east, pumping
better boundary layer moisture northward through
central/northern Kentucky. Most dewpoints in the area are in the
50s, but mesonet stations across Kentucky are already
indicating mid to upper 60s dewpoints entering the local area.
Light southerly flow will continue to usher in this better
moisture over the next few hours before flow becomes more
southeasterly this evening. This tongue of moisture will be
directed northwestward, combining with the better surface
moisture ahead of the approaching front. This moisture will be
critical for humidity and thunderstorm development tomorrow
afternoon.

Even with the better moisture entering the area this evening, no
rainfall is expected with forcing remaining quite weak. After
the afternoon cumulus dissipates, a few scattered upper level
cloud linger into the early evening. Eventually, skies will
clear with temperatures dropping into the upper 60s and lower
70s.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
There is some potential for showers and thunderstorms to be
ongoing early Wednesday morning across central Indiana. Whatever
remnant activity moves into central Indiana will struggle to
survive into the local area due to the corridor of lower
dewpoint values across eastern Indiana and western Ohio. Even if
the thunderstorms weaken, outflow boundaries and cloud debris
will play a role in temperature and rainfall forecasts later in
the day. At the same time, low level moisture will continue to
improve (low 70s and perhaps mid 70s) as the convergence
increases along the boundary. The increasing moisture and
forcing along the front/other boundaries will ultimately lead
to thunderstorm development during the afternoon and through the
evening. All three of the below impacts remain noted in the
HWO...

Heat: Confidence is fairly high that cloud debris will enter the
area through mid-morning. Depending on how quickly this clears,
some disruption to heating will be possible. Additionally, low-
level moisture will be increasing during the day. Given this
uncertainty, local heat conditions may rapidly change from the
mid-morning hours into the early afternoon. Then, developing
thunderstorms may quickly erode heat advisory conditions that
have ultimately developed. The most likely area for a short-
fused heat advisory would be across northern Kentucky, southwest
Ohio, and southeast Indiana.

Severe: Day 2 Slight Risk (Level 2 of 5). With the heating and
increasing boundary layer moisture, clusters of strong to
severe storms are possible Wednesday afternoon and evening.
Damaging wind gusts are the main threat with some hail possible
if an updraft split is able to change mean storm motion. At this
time, downburst winds appear to be the more likely storm mode
with limited ability for organization into bowing segments.

Heavy Rain/Flooding: While much of the area remains quite dry,
stalled boundaries situated in a very moist atmosphere, in
July, should always be viewed as potential heavy rain producers.
Ultimately, storm mode and boundary orientation remain the key
factors. The latest 18Z HRRR shows how some back-building
activity could provide isolated corridors of 2-3"+ into the
evening hours. This would be beneficial rain for the abnormally
dry conditions, but a few flood advisories may be possible in
the heavier/more flood prone areas.

Thunderstorm coverage is expected to decrease a little during
the overnight activity, but continue mid-level forcing and
remnant instability will keep the threat lingering into Thursday
morning.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
East-west oriented front will extend across the area at the
beginning of the period. High precipitable water and deep warm
cloud depths will extend along this same corridor. As a short
wave moves across the area, showers and thunderstorms will occur
with heavy rain potential and perhaps some damaging winds being
the concern. Exactly where that boundary sets up, which latest
data suggests will be near I-70, will have a greatest threat of
heavy rain with the possibility of training and backbuilding.

As that impulse moves off to the east, there will be a relative
lull in showers and any storms through late Thursday night.
During this time the boundary will lift north. More showers and
storms will occur Friday, especially in the afternoon in part
due to a pre- frontal trough pushing through the area. Airmass
will be the same as on Thursday, so locally heavy rainfall will
remain possible although convective elements will be progressive
and less prone to training. Damaging wind threat will also
persist.

The cold front will not move through until Friday evening with
the chance of showers and thunderstorms lingering until that
passes. High pressure will build in for the weekend and still be
influencing the region into Monday. The next cold front will
approach and move through the area Monday night into Tuesday
bringing the next chance of showers and thunderstorms.

Warm, muggy airmass ahead of the first cold front will get
replaced by something more seasonal for the weekend. But
temperatures and dew points will be rising again early next week
ahead of the next system.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
VFR conditions are forecast through the TAF period.

Winds are currently southeasterly to southerly this afternoon
generally around or less than 10 knots. This will continue
through the evening hours before becoming more southwesterly
between 09Z-12Z. Expect winds over 10 knots with gusts around 20
knots after 15Z.

Will continue to see upper level clouds through the rest of the
afternoon with clearing this evening. Additional mid to upper
level clouds move in overnight through tomorrow morning. Better
moisture in place tomorrow allows for shower and thunderstorm
development after 18Z tomorrow. Confidence in thunderstorm
coverage is low at this time so initiated precipitation mention
as VCSH at CVG starting at 20Z.

OUTLOOK...Thunderstorms possible Wednesday through Friday.

&&

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

&&

$$
SYNOPSIS...Hickman
NEAR TERM...McGinnis
SHORT TERM...McGinnis
LONG TERM...
AVIATION...McGinnis