688
FXUS61 KILN 091749
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
149 PM EDT Tue Jul 9 2024

.SYNOPSIS...
Moisture will interact with a weak surface trough that slides
into the area leading to a few showers this morning. This is
ahead of the remnants of Beryl which are forecast to track from
the Southern Plains into the Lower Mississippi Valley today and
then northeast across the area tonight and into the Great Lakes
Wednesday. Moisture will increase with widespread precipitation
developing late in day into tonight. Locally heavy rain will be
possible. High pressure will then build in for Thursday and
Friday offering dry weather.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Ongoing fcst remains largely on-track, with only subtle timing
changes to the onset of showers/storms later today. In the
meantime, a blanket of mid/high clouds remains entrenched across
the area, with only a few breaks in the cloud cover now
beginning to emerge in parts of central KY, which should spread
to the NE into the local area by early afternoon. However, skies
in general will remain mostly cloudy, which may slow (but not
stop) destabilization efforts as we progress later into the day.
Do think that guidance like the HRRR continues to be underdone
regarding afternoon convection/storm coverage, especially in the
Tri-State/northern KY, owing to initializations that are far
too dry (dewpoints too low) compared to obs. So there may be a
bit more in the way of storms by mid afternoon, even with the
expectation that the primary severe threat will evolve mid/late
evening.

The one item that shouldn`t be overlooked will be the torrential
rainfall rates with any of the activity through early tonight.
PWATs in excess of 2" will overspread parts of the area by this
evening, with extremely efficient rainfall rates expected in the
heaviest activity. Luckily, the storms should be moving fairly
quickly to the northeast, but any brief training or backbuilding
will undoubtedly cause localized issues if it occurs in
vulnerable/flood-prone locales. The forward motion of the
activity should preclude a more widespread flash flood threat,
but certainly 1-2" seems very likely in a few spots, especially
near/W of the I-75 corridor through this evening.

PREVIOUS DISCUSSION...
Sheared out northern stream shortwave pivots thru the Great
Lakes with weakening surface trof slipping into the northwest
and dissipating. Forcing is weak but with isentropic lift across
the northwest a few showers will possible across the west-
northwest this morning.

Remnants of Beryl is forecast to eject northeast from the
Southern Plains into the Lower MS Valley by evening. A warm
front is forecast to develop into ILN/s southern forecast area
ahead of this low pressure system this afternoon. Scattered
showers and embedded thunderstorms are expected to increase in
coverage across the southwest in a region of favorable moisture
transport.

As a 40-45kt southerly low level jet comes into play this
evening expect showers and embedded thunderstorms to increase in
coverage. Hodographs will take on a favorable orientation with
backed low level winds and increased flow. Also, LCLs will lower
as column moistens up. Instability around 1000 J/kg will be
possible across the south late in the day into this evening
when conditions could become favorable for tornadoes, which is
observed on the eastern side of tropical remnants.

The degree of instability is uncertain so this situation is
highly conditional with regards to tornado potential but will
be closely monitored this afternoon and evening.

Showers and some thunderstorms will become widespread generally
north and west of I-71 tonight. Given the expected track of the
surface low, the most favored region of widespread heavy rain
is expected to be to our west. But with tropical moisture (PWATs
2+ inches, cannot rule out the potential for locally heavy
rainfall.

Expect a gradient in temperatures on today with highs in the
lower 80s northwest to the lower 90s in the southeast. Lows
tonight will be in the upper 60s west to the lower 70s east.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
Surface low over Indiana to lift northeast across the Great
Lakes Wednesday. Widespread showers and embedded thunderstorms
to pivot northeast of the area but a continued threat for pcpn
persists with trailing surface cold front pivoting thru the
area. Pressure gradient increases around the low with west winds
gusting up to 35 to 40 mph possible.

Temperatures on Wednesday will be cooler - ranging from the
mid/upper 70s northwest to the lower 80s southeast.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
The remnants of Beryl will be moving northeast of the area on
Wednesday night. A trailing cold front will be pushing east of the
area at the same time and cooler, drier air will be moving into the
Ohio Valley. Rain chances reduce through the night. Forecast lows
drop into the lower to middle 60s. Temperatures remain on the cool
side for Thursday and Thursday night when the winds remain out of
the northwest.

Southerly winds redevelop over the area by Friday and persist into
the start of next week. Temperatures return to above average along
with high humidity. Diurnal instability will be possible each day
along with chances for showers and storms each afternoon.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
An unsettled TAF period is on tap as several rounds/clusters of
SHRA/TSRA are expected through 00z before a more widespread
arc/band of SHRA/TSRA pivots to the NE through the local area
between about 02z-07z. There is the potential with any of this
activity for abrupt reductions in VSBYs, potentially to IFR, in
the heaviest rain rates. The SHRA/TSRA activity should wane in
coverage after 07z, with only a stray SHRA possible thereafter.

Once the SHRA/TSRA activity ends, attention will turn to an
unseasonably breezy period, especially during the daytime
Wednesday. Light easterly winds around 5kts this
afternoon/evening will become more southerly tonight at around
10kts before going more out of the SW after 12z Wednesday. SW
winds of 15-20kts, with gusts to around 30kts, are expected
by/after 18z Wednesday. Winds will become more westerly, and
eventually northwesterly toward 00z Thursday before subsiding
gradually.

VFR CIGs will prevail through this evening, although suppose a
brief MVFR CIG cannot be ruled out in the heaviest TSRA activity
before then. Toward 06z and beyond, MVFR CIGs will develop and
expand from NW to SE, with CIGs eventually going lowering to
1kft-2kft by 15z Wednesday. CIGs will slowly lift/scatter out
toward 00z Thursday.

OUTLOOK...MVFR CIGs are likely Wednesday afternoon.

&&

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

&&

$$
SYNOPSIS...AR
NEAR TERM...KC/AR
SHORT TERM...AR
LONG TERM...Campbell
AVIATION...KC