-- Discussion containing changed information from previous version are highlighted. --
186
FXUS61 KILN 071104
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
704 AM EDT Tue May 7 2024

.SYNOPSIS...
Several rounds of showers and storms are expected through
Thursday amidst a continued warm and humid pattern. Slightly
cooler air will filter into the region late in the week, with
slightly drier conditions also expected. However, periodic
chances for showers will likely linger into the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Vigorous low pressure over the northern Plains will lead to a moist
southwest flow of air across the Ohio Valley today. A decaying band
of showers with isolated thunder is expected to slide east through
the region late this morning through early this afternoon. Severe
storms are not expected with this band.

As a shortwave is ejected northeast from the southern Plains into
the Ohio Valley, an increase in mid- level flow and backing low-
level winds will be seen in the vertical profile by later in the
afternoon. A surge in warm, humid air will likely occur just ahead
of the shortwave`s arrival. Forecast soundings from the HRRR are
concerning, with surface CAPE late this afternoon into the early
evening approaching 2,500 J/kg and effective shear reaching around
60 knots. Curved hodographs lead to effective SRH exceeding 200
m^2/s^2.

The latest guidance suggests a less forced environment late this
afternoon, so scattered, discrete supercells are expected. All
hazards appear likely with these storms. High temperatures will
reach into the upper 70s to lower 80s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
A cold front associated with the shortwave will shift east across
the local forecast area late this evening through midnight. While
hodographs are a bit less curved for this period, an increase in
forcing leads to higher coverage of thunderstorms, and likely a more
organized linear mode. Can`t rule out some embedded supercells as
well based on persistent bulk shear ahead of the front.

The shortwave will exit to the east late tonight, leading to a
quieter conditions extending into Wednesday. Bright May sunshine
allows high temperatures to exceed 80 degrees across the middle Ohio
Valley. We may see some increase in cloud cover late in the period
as another shortwave begins to eject northeast into the middle
Mississippi Valley.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A warm frontal boundary will be draped along the Ohio River early
Wednesday evening, extending east from a surface low over the mid
Mississippi Valley. As the low tracks east Wednesday night, the
boundary will begin to lift slowly north across southern portions of
our fa. There remains some uncertainty with just how far the front
will make it, along with the better instability, but the 00Z models
appear to have trended everything a bit farther to the south. Still,
expect to see showers and thunderstorms overspread the region
Wednesday evening and continue into the night as the surface low
moves through our area.

With very favorable shear and an instability gradient along the
boundary, some severe storms will be possible, with the best chances
mainly along and south of the Ohio River, closer to the better
instability.  Damaging wind and large hail will be the main severe
threat, although an isolated tornado will also be possible. Also,
with the potential for training storms along the boundary and PWs in
the 1.5 to 2.0 inch range, there will be a heavy rain/flood threat,
especially across southern portions of our area Wednesday night.
Pcpn will taper off later Wednesday night into Thursday morning as
the low moves off to the east.

An upper level trough will settle in across the Great Lakes and Ohio
Valley heading into the weekend and into early next week. A series
of embedded mid level short waves rotating through the trough will
bring additional chances for showers and a few thunderstorms each
the day, especially Saturday afternoon and evening. Temperatures
will be seasonably cool through the weekend with highs mostly in the
60s. More seasonable temperatures will return on Monday with highs in
the low to mid 70s.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Early morning low stratus and patchy fog will lift by mid-
morning as cirrus increases ahead of a weakening arc of showers
and storms moving in from the west. Heading into the afternoon,
impacts from scattered to numerous storms -- some severe -- will
be the primary concern. Timing these is a challenge due to
uncertainty in the increase in coverage of the developing
storms. For now have included VCTS with the understanding that
storms are likely to be on station at some point during the late
afternoon through late evening hours.

Clouds will begin to decrease after 06Z as the weather system
exits to the east. Will need to watch for stratus/fog
development in the pre-dawn hours if the clouds clear early.

OUTLOOK...Thunderstorms will be possible late Wednesday into
Wednesday night. MVFR/IFR CIGs are possible Wednesday night into
early Thursday and again on Friday.
-- End Changed Discussion --

&&

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

&&

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