460
FXUS61 KILN 181706
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
106 PM EDT Thu Jul 18 2024

.SYNOPSIS...
High pressure will build in and persist through the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Forecast on track...changes were cosmetic to current cloud
trends based on satellite imagery.

18.12Z KILN sounding sampled a very dry troposphere - with PWAT
below the 10th percentile for mid-July (0.66"). While not a
daily record, this is an extremely dry airmass for this time of
year (pretty much the peak of the climatological PWAT curve).
Despite this, strong cold advection (daily high temps about 10F
below normal) will work with residual moisture at the top of
the mixed layer under the subsidence inversion to allow cumulus
to develop with heating, and we`re already seeing that over the
Bellefontaine Ridge and across areas of central Ohio. With time,
this will tend to mix out a bit as the boundary layer deepens
and mixes further. The cirrus canopy now along/southeast of I-71
will carry slowly southeast through the day, so increasing
amount of sunshine for all around the fair weather cumulus.
Northern areas likely remain in the 70s...while low 80s creep
into areas along/south of the Ohio River.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Center of the high will sink into the lower Great Lakes and
remain there through Friday. This will keep temperatures below
normal with relatively low dew points for this time of year.
Short wave passing well south of the region will spread some
high clouds into the area on Friday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
The extended period begins with surface high pressure stretching
from the middle Mississippi Valley through the lower Great Lakes
into the northeast United States. This high will keep below normal
temperatures and relatively low dewpoints over our area... at least
through the weekend.

As we get into Monday, the high weakens. This will allow warmer and
more humid conditions to start working to the north accompanying
light southerly flow. We could start seeing a few isolated showers
and storms in the south on Monday afternoon.

To close the period on Tuesday and Wednesday, deeper southwesterly
flow will provide for a higher chance of storms along with the
return of warm, muggy conditions. While guidance is relatively
consistent on this pattern shift in the mid-term, have held PoPs in
the chance category for now due to the lack of a more organized
signal for higher precipitation coverage.

&&

.AVIATION /17Z THURSDAY THROUGH MONDAY/...
Scattered to locally broken VFR cumulus will remain over the TAF
sites this afternoon, but will tend to decrease as the afternoon
wears on due to continued dry advection and warming/mixing of
the boundary layer. North-northeast winds of 7-10kts may locally
gust to 16 or 17kts or so, but it should be the exception and
not the norm. Rapidly cumulus dissipation is expected later this
afternoon/evening, with winds remaining above 5kts for most of
the night, except for lower/valley locations like LUK/LCK. At
LUK, think there will be enough drop off in wind to allow some
valley fog to develop, so included a TEMPO of 2SM for a few
hours. After sunrise, winds will turn more northeast under clear
skies. A few VFR cumulus will likely form again during the day
on Friday.

OUTLOOK...No significant weather is expected at this time.

&&

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

&&

$$
SYNOPSIS...
NEAR TERM...Binau
SHORT TERM...
LONG TERM...
AVIATION...Binau