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000
FXUS61 KILN 131738
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
138 PM EDT Sat Apr 13 2024

.SYNOPSIS...
Dry and sunny conditions will prevail today with near normal
temperatures. A much warmer airmass will build into the Ohio
Valley Sunday through the first half of the workweek, with
several chances for rain and storms. Cooler and drier air
returns to the area by the end of the workweek through next
weekend.

&&

.NEAR TERM /UNTIL 9 PM THIS EVENING/...
Northwest flow pattern aloft with surface ridge axis building
into the region this afternoon. Abundant sunshine will be
observed with perhaps only a few diurnally driven cumulus clouds
this afternoon.

Temperatures will warm to highs from near 60 northeast to the
upper 60s southwest.

Breezy conditions will develop this afternoon with west winds
gusting up to 25 mph at times.

&&

.SHORT TERM /9 PM THIS EVENING THROUGH 6 PM SUNDAY/...
Tranquil conditions are expected tonight, although there will be
somewhat of a pattern shift beginning to evolve as the midlevel
flow pattern shifts from sharply out of the NW to a much broader
NW flow regime, which will persist into the day Sunday. In the
LLs, the ridge axis will shift to the E, allowing for southerly
return flow to again resume into Sunday morning as a weak sfc
low darts E across MI near/after daybreak.

Lows tonight will dip into the mid 40s in central OH to the
lower/mid 50s W of I-75 corridor. Slightly better LL flow will
become established later into the nighttime, especially across
the E, helping keep temps a few degrees warmer in EC/SE IN than
will be the case in NE KY and central OH.

For the daytime Sunday, a midlevel S/W will dig into the
interior NE CONUS, with an attendant weak sfc low darting E from
MI into the ern Great Lakes during the afternoon. On the srn
flank of the low, back to the SW toward the OH Vly, an enhanced
LLJ will nose to the NE through the region as stronger SW flow
near the sfc will help usher in some better moisture in the
lower part of the profile. As this occurs, a plume of drier air
aloft should also move E into the region, helping steepen
midlevel lapse rates and increase deeper-layer instby. The stout
EML should allow for midlevel lapse rates greater than 7.5-8C/km
to overspread from the W during the day amidst a moistening LL
profile. All of this points to the likelihood of MLCAPE
~1000-1250 J/kg developing, especially for locales near/N of
I-70 in the region of better LL moisture availability
immediately ahead of the southward-sagging front.

While there should be instby that develops in the region Sunday
afternoon into the evening, the cap may hold through most of the
daytime until the impressive EML inserts itself into the
profile late in the day and some erosion of CIN occurs. LL wind
profiles should be largely veered, with some subtle deep-layer
directional and speed shear to work with, creating elongated and
slightly curved hodographs. This, combined with the increasing
buoyancy late in the day and the front sagging S through the
nrn/ern OH Vly though provide enough of a combo of
instby/shear/lift to initiate some clusters of TSRA by late
afternoon through the evening, primarily in the nrn/ern half of
OH. Current data suggests the best forcing should exist in far
ern/NE OH, with much weaker forcing further to the WSW toward WC
OH, even by late in the day. So... there are considerable
uncertainties regarding convective coverage with westward
extent during this time period (especially if the pronounced
cap is able to hold through early evening), with the greatest
coverage of storms likely to focus during the evening in
central and east-central OH, eventually drifting further to the
S late in the evening. However, as this occurs further past
sunset, instby should be waning, as should the already-meager
forcing, as the front slows to a southward crawl through the
night. So the time period of concern, especially as it relates
to a few strong to severe storms, appears to be relatively small
at this juncture (mainly in the several hour period around
sunset), with some storm/severe potential perhaps persisting a
bit past sunset. There is enough of a signal for /some/ overlap
of moderate instby, erosion of the cap, and sufficient deep-
layer shear to suggest that a few strong to severe storms (with
strong/damaging winds and large hail being the primary threats)
are going to be possible, mainly Sunday evening in the ern/NE half
of Ohio. The most-favorable area locally for this would be in
central OH, although certainly it cannot be ruled out in WC or
south-central OH, either. Expect that locales near/S of the OH
Rvr in parts of N KY and SE IN may not see much (if any at all)
as the front finally makes it to these areas much later in the
night toward daybreak Monday.

Despite the uncertainties regarding both convective initiation
and coverage, will highlight the potential for a few strong to
severe storms (especially in central OH and points near I-70)
for Sunday evening in the HWO.

Highs on Sunday climb into the mid to upper 70s amidst a stiff
SW breeze gusting to ~25kts at times once again.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
A weakening low moving from the Great Lakes to the Northeast will
see a trailing cold front develop into a stationary boundary
overnight Sunday. This leads to a low chance of showers in the
forecast Sunday evening given a limited amount of forcing. The
stationary front should remain near the Ohio River through early
Monday evening before washing out overnight in developing southeast
flow.

Warm frontal processes look to develop early Tuesday as mid level
vorticity pools on the back side of a progressive eastward moving h5
ridge. Models are generally sparing with rainfall in this
environment and the GFS appears to be overdone in it`s vorticity and
subsequent rainfall, particularly Tuesday morning. The warm front
lifts north later in the day and then warm sector showers are
expected overnight ahead of the cold front. Showers and
thunderstorms will continue Wednesday morning and be maximized in
the afternoon in concert with the passage of a cold front. The front
and associated rainfall quickly move east and away from the CWA by
nightfall.

Zonal flow sets up and continues through Thursday. Models have
strong differences in mass fields overnight and into Friday. Very
low chances for rainfall are noted in forecast builder for this time
which seems opposite from GFS and ECMWF, though neither of these are
supporting one another`s solution.

Mild conditions with highs in the 70s to around 80 are expected
through Wednesday, cool off to normal in the mid 60s to 70 Thursday,
and even moreso on Friday with mid 50s to 60 for highs. Lows will
follow a similar vein, 50s Sunday and Monday nights, low 60s Tuesday
night, 50s Wednesday night dropping to the 40s at the end of the
forecast for Thursday night.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
VFR is forecast to continue as high pressure tracks across TAF
sites. There will be mainly clear skies through tonight in the
very dry airmass. Northwest winds gusting over 20 knots early in
the forecast will subside and back to southwest tonight. Wind
shear is indicated late tonight to Sunday morning under a
strengthening low level jet.

For Sunday, a disturbance moving to the Great Lakes will allow
increasing clouds, while winds gust over 20 knots again during
the afternoon. Kept any mention of thunder out of the forecast
since storm development is expected farther east and after 18z.

OUTLOOK...Thunderstorms are possible Tuesday and Wednesday.

&&

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

&&

$$
SYNOPSIS...KC
NEAR TERM...AR
SHORT TERM...KC
LONG TERM...Franks
AVIATION...Coniglio