296
FXUS61 KILN 161750
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
150 PM EDT Sun Jun 16 2024

.SYNOPSIS...
Building high pressure aloft will combine with surface pressure
increases and a southerly flow in the Ohio Valley to bring an
atypically extended period of high temperatures for the coming
week. Highs in the mid to upper 90s will be compounded by low
temperatures from 70-75, worsening any heat related issues a
little more each successive day. Some weak disturbances along
with daytime heating may trigger thunderstorm activity on
Monday and possibly Tuesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
No changes appeared to be necessary with the updated forecast
this noon hour.

Surface high off the east coast combined with rising mid level
heights from the building ridge will result in another dry day
with little cloud cover, other than some thin cirrus, and
rising temperatures with most if not all parts of the forecast
area reaching 90.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Mid level high centered over the Carolinas will become more
expansive during the period. Meanwhile instability will develop,
at first aloft tonight and then becoming surface based on
Monday. Cannot rule out an elevated shower or storm overnight in
southeastern counties. But better chance will be on Monday.

Convective allowing guidance is giving mixed signals about the
potential for storms on Monday. Most 00Z solutions suggest that
activity will be in the mid to late afternoon with greatest
coverage in the Tri-State as a weak disturbance lifts up the
back side of the ridge. What is more unclear is whether there
will be storms earlier in the day as convective temperature is
reached. That is the minority solution but certainly a
possibility and worthy of low chance PoPs.

There will be plenty of instability available with little to no
shear. DCAPE is forecast to be high, so any storms that can
become more robust on Monday will have the potential to produce
downbursts.

Lows tonight will be in the upper 60s to lower 70s with highs in
the lower to mid 90s. With dew points rising into the upper 60s
to lower 70s, maximum heat indices will be around 100. This is
heat advisory criteria. But with the extended period of heat
coming, and in collaboration with neighboring offices, have
opted to issue an excessive heat watch.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Any shower/storm activity that develops on Monday will gradually
wane Monday night with the loss of diurnal heating. A few storms may
linger into the early part of the night depending on ongoing
convection and residual outflow boundaries that modify the
environment. However, storms will likely become elevated overnight
and thus limit severe potential.

A chance for showers/storms continues on Tuesday as a weak
disturbance moves along the western periphery of the broad area of
high pressure. The exact location of the high will play some role on
storm placement and overall coverage. Of course, any convection that
does occur will modify the environment to some capacity, which could
lower daytime highs for some. This is one of the uncertainties in
forecasting exactly how high surface temperatures and thus heat
indicies will get. Given that dewpoints will be in the upper 60s to
middle 70s, heat indicies are still forecast to hover around the 100
degree mark Tuesday.

The area of high pressure is expected to expand westward by the
middle of the week. In turn, this will favor a drier forecast, but
also offer minor relief in the humidity as surface flow shifts
towards the southeast (instead of southwest). Still, dewpoints are
expected to remain in the lower to upper 60s the rest of the work
week and into the start of next weekend. The air will still feel
muggy, but dewpoints around these values won`t cause a notable
uptick in heat index values. Thus, we are not anticipating reaching
our typical Heat Warning criteria of 105+ degree heat indicies. In
fact, heat indicies may struggle to even climb to the 100+ degree
mark based on latest guidance, even with air temperatures already in
the middle to upper 90s for most. Regardless of this, the effects of
heat stress will still be felt as hot daytime highs in the 90s and
very mild overnight lows in the 70s will offer no period of relief.
The prolonged nature of this heat wave is what will cause the stress
and any other heat related impacts.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR conditions will be found over the region, with some 5-6kft
sc/cu possible from about midnight through daybreak. Some few
models are trying to indicate some low chances of precip, but if
something were to fire overnight, it would be very isolated in
nature and not likely to affect any terminal.

A similar setup is in the offing for tomorrow afternoon as
heating and mid level energy combine to spark scattered
thunderstorm activity beyond 18z. Given the detractors of
unknown placement and if the convection starts, did not include
this in the extended 30 hour CVG TAF.

Light southerly winds are expected to be 5-6kt this afternoon
and during daylight hours on Monday. Overnight they will be
generally light from the south if it does not go calm or
light/variable.

OUTLOOK...No significant weather expected.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Excessive Heat Watch from Monday afternoon through Friday
     evening for OHZ026-034-035-042>046-051>056-060>065-
     070>074-077>082-088.
KY...None.
IN...Excessive Heat Watch from Monday afternoon through Friday
     evening for INZ050-058-059-066-073-074.

&&

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