FXUS61 KILN 180542
AFDILN
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
142 AM EDT Fri Jun 18 2021
.SYNOPSIS...
A decaying system will be approaching late in the overnight and
into the early morning hours on Friday. Severe thunderstorms
will develop during the late afternoon and into the evening
hours on Friday. Heavy rainfall will also be possible.
Thunderstorm activity and the potential for severe weather will
again be possible on Saturday as the boundary remains in place
across the region.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Some storms firing in west central IN/east central IL ahead of
the line of decaying showers over nrn IL/srn LMich. Took this
and a few very minor returns over nw IN and blended them into
the 12z forecast to account for movement, but no models were
showing any kind of initiation in this section at all tonight,
so this appears to be a wildcard in play that will likely affect
the forecast updates tonight, especially if the CAMs take a
while to see this and adjust.
Low temperatures overnight are expected to drop down into the
middle 50s to the middle 60s.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
An active weather pattern will be in place for Friday into
Friday night. A decaying MCS will continue to move into northern
portions of the region during the morning hours. There are some
model solutions that bring this feature further south and this
would have implications for afternoon placement of convective
development. At this point in time have a slight chance to
chance of precipitation for locations generally north of the
Ohio River with likely precipitation generally north of
Interstate 70. This feature will then likely lay out a boundary
for convective development during the late afternoon and into
the evening hours. Winds will pick up for the afternoon hours
and have wind gusts upwards of around 25 to 30 mph outside of
thunderstorms.
There are some concerning signals for a higher end damaging wind
event late Friday afternoon into Friday night. CIPS analogs
also are supportive of this and SPC has a large portion of the
region in an enhanced risk. Given shear profiles there is also
at least some tornadic and hail potential as well. Added severe
wording into the forecast
Friday night the flow becomes more west-east oriented. With this
flow orientation there will be flooding concerns as well. A
flood watch will be needed in the future, however held off for
now to try to fine tune where the axis of heaviest rainfall will
be.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Long term period begins with potential storm complex in the
south as the upper energy heads east along a mostly stationary
front. Guidance varies as to how long the convection persists,
with the 3-km NAM on the drier side and the HRRR keeping
convection going until it exits into southeast Ohio late
Saturday morning.
While warm muggy conditions continue Saturday into Sunday, forcing
looks to be rather weak as the frontal boundary dissipates. Expect
PoPs to decrease considerably during this time with isolated diurnal
convection remaining in the grids due to conditional instability.
High temperatures will peak in the mid to upper 80s each day, with
lows in the upper 60s.
For Monday, a stronger, more progressive cold front dives southeast
through the region. Uncertainty is high as far as timing the front.
ECMWF and its ensemble are slower, with FROPA occurring Tuesday
morning, and the GFS system quicker with FROPA on Monday evening.
Uncertainty is amplified by the slow progression of tropical
remnants moving through the southeast United States Sunday into
Monday. Despite uncertainty, there is certainly some concern about
strong to severe storms firing along and ahead of the front
beginning Monday afternoon into the evening.
Behind the front, decreasing clouds and cooler, drier air arrives
with surface high pressure starting to build in after noon on
Tuesday. In fact, model blend has dewpoints dropping into the upper
40s to lower 50s Tuesday night and Wednesday. Highs stay in the low
to mid 70s.
The high shifts to the east on Thursday with max temperatures
returning to near 80.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Showers and thunderstorms moving into the southern Great Lakes
early this morning are forecast to gradually weaken through the
morning hours as they move into northern Ohio. Convective
allowing models are generally keeping pcpn associated with this
initial batch of pcpn north of the northern TAF sites. The
airmass is then forecast to destabilize through the afternoon
with a boundary laying out west to east across the region. This
will serve as a focus for additional shower and thunderstorm
development later this afternoon and into this evening. There
is still some uncertainty with the exact location of this so
will generally just allow for prevailing showers with a VCTS to
sag south across the TAF sites starting from late this
afternoon and then persisting into tonight. Some of the storms
will be capable of producing wind gusts in excess of 50 knots
late this afternoon into this evening. Locally heavy rainfall
and reduced visibilities can also be expected at times with the
storms.
.OUTLOOK...Thunderstorms are possible through Saturday and again
on Monday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Novak
NEAR TERM...Franks
SHORT TERM...Novak
LONG TERM...Hogue
AVIATION...JGL
