-- Discussion containing changed information from previous version are highlighted. --
213
FXUS61 KILN 222323
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
723 PM EDT Wed May 22 2024

.SYNOPSIS...
Episodic showers and thunderstorms are expected through the end
of the work week and weekend. Temperatures are expected to trend
above normal through the weekend before a stronger system
impacts the Ohio Valley Sunday into Monday, which will reduce
temperatures to near normal at the beginning of the next work
week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --
Early evening update...
A line of storms has rapidly formed west of the I-71 corridor
from west-central Ohio into southeast Indiana. Atmosphere
currently consists of sufficient SBCAPE (~1500-2500 J/kg) and
modest bulk shear of 30-40 knots. This will allow for quasi-
organized storms with the potential for locally damaging wind
gusts and large hail. This activity will spread eastward over
the next few hours. Since these storms have formed on the
western edge of the CAPE envelope, activity is likely to
continue after sunset as the rest of the instability is used.

Previous discussion...
A relative minimum in convection is expected through the bulk
of the afternoon hours. CAMs continue to be fairly meager with
any initiation during peak heating hours when CAPE and lapse
rates (particularly in the lower levels) will be more conducive
for strong/severe storm potential. Thus, while the afternoon
period will still have to be monitored for any CI, it does not
appear favorable. If any storms do happen to materialize, the
primary threats would be localized downbursts and large hail -
wind shear is not strong/favorable enough to warrant a tornado
concern.

There is a better signal in CAMs for convection during the
evening and overnight period, with slightly better forcing.
Minor improvement to wind shear values expected as well, which
could lead to a better window of severe potential mainly during
the late evening and early overnight period. However, this
potential will likely still be limited given the lack of strong,
dynamic forcing. Additionally, the cold front that tries to work
through our CWA becomes pretty washed out and thus doesn`t
provide the best surface mechanism for organized convection.

Storm activity will begin to wane around the middle of the
night, mainly around 12AM - 2AM. A few light showers may linger
a bit longer, particularly in portions of central OH down
through northern KY.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
A slight cooldown is forecast on Thursday, but temperatures
still trend slightly above seasonal normals. Chances for showers
and thunderstorms will be lower on Thursday, but still linger
given the stalled, weak frontal boundary laying across our CWA.
Locations north of I-70 have the best chance to remain dry all
day, and will also experience slightly lower temps and
dewpoints. Elsewhere, isolated to scattered storm develop still
possible throughout the day, particularly in the afternoon and
evening when we are near peak diurnal heating.

Boundary continues to lift north as a warm front Thursday night.
However, shower/storm coverage will become less extensive
Thursday night.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
In westerly flow aloft, a weak mid level short wave will progress
east across the Ohio Valley later Friday afternoon into Friday
night. Some weak destabilization through the afternoon on Friday
will lead to a chance of showers and thunderstorms, with a better
chance overspreading the area heading into Friday evening as the
short wave moves in. Pcpn chances will then diminish heading into
Saturday as we get on the back side of the short wave.

Another mid level short wave will lift northeast into the Ohio
Valley during the day on Sunday as a stronger secondary short
wave/mid level low pivots northeast out of the mid Mississippi
Valley and into the Great Lakes Sunday night through Monday. This
will allow for an associated surface low to lift northeast from the
central Plains on Sunday into the central Great Lakes through the
day on Monday. Increasing moisture/forcing ahead of this system will
lead to developing showers and thunderstorms Sunday afternoon into
Sunday night and continuing into the day on Monday. Given the
strengthening wind fields and track of the surface low, some severe
storms will be possible, especially later Sunday afternoon into
Sunday night.

An upper level trough will eventually settle in across the Great
Lakes and Ohio Valley region through early to mid next week.
Additional embedded mid level short waves rotating through the
trough will keep some lingering chances for showers and
thunderstorms through the remainder of the long term period.

Temperatures will remain above normal through the weekend with
daytime highs mostly in the upper 70s to lower 80s. A more seasonable
airmass will then move into the region through early to mid next
week with daytime highs mostly in the lower to mid 70s.

&&

.AVIATION /00Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
A line of storms has formed from west-central Ohio into
southeast Indiana. As these continue eastward, there is
potential for this line to impact all TAF sites. Will adjust
timing with amendments over the next couple of hours. For now,
have onset of thunderstorms at the beginning of the TAF with
CVG/LUK/ILN at 1Z. Expect updates to CMH/LCK as the line moves
east.

Otherwise, the rest of the forecast remains on track as the
boundary slides through into the overnight. Winds will weaken
and become variable around 5 kts with this washed out boundary.

Maintained mentions of MVFR CIGs developing Thursday morning.
Better chances and coverage expected for KCVG/KLUK and perhaps
KILN. Confidence is lower on northern terminals with cloud
heights potentially remaining SCT or at VFR heights into the
afternoon.

OUTLOOK...Thunderstorms possible at times through Sunday. MVFR
ceilings possible early Thursday.
-- End Changed Discussion --

&&

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

&&

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