027
FXUS61 KILN 311056
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
656 AM EDT Mon Mar 31 2025

.SYNOPSIS...
Surface high pressure will begin to build into the Ohio Valley late
Monday into Tuesday, providing dry and cool weather. Another strong
low pressure system will bring thunderstorms and the potential for
heavy rain late Wednesday. Additional waves of low pressure will
continue the chance for stormy weather late in the week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Low pressure in southeastern Ontario will move northeast into
southern Quebec this morning. This will drag and cold front through
the middle Ohio Valley this morning. Behind the front, conditions
will begin to dry out as cooler air is ushered into the CWA with
northwesterly flow. Temperatures will slowly fall through the 50s and
into the 40s by evening.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
Surface high pressure will build into the Ohio Valley tonight into
Tuesday. After cool morning lows in the 30s Tuesday morning, highs
will reach into the 50s during the afternoon. Clouds will decrease
under the high, so mostly clear skies are expected.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Following a quiet start to the long term period, a very active
period, with potentially significant weather, is expected to unfold
midweek through the weekend, with an extended multi-hazard pattern
likely for the OH Vly through the second half of the workweek
through the weekend.

Dry air initially entrenched across the region will be shunted out
of the region quickly into Wednesday morning as a warm front pivots
to the NE through the area. This will be in response to the
progression of a seasonably deep (<990mb) sfc low into the Upper
Midwest as a deepening closed mid/upper level low drifts into the
upper MS Rvr Vly by Wednesday afternoon. This will allow for rapid
LL moisture advection into the area, which may be accompanied by
some convection during the morning hours on the nose of the potent
LLJ impinging to the NE into the region. This robust moisture/mass
convergence will provide some ascent to initiate SCT to numerous
TSRA Wednesday morning into early afternoon, which will arc to the
NE into midday and away from the local area by peak heating.

The bottom line is that the setup for severe weather Wednesday
afternoon into the evening is quite concerning as the overlap of
modest to strong instby (expanding in from the SW) amidst very
strong LL/deep-layer wind fields suggest numerous ingredients will
be in place for SCT to numerous severe storms across the region as a
whole, particularly Wednesday evening. The details of this
evolution, of course, will ultimately dictate the scope, magnitude,
duration, and type of severe weather locally. But from a
pattern/ingredients-based perspective, there is increasing
confidence in the potential for a significant severe weather event
Wednesday evening into early Wednesday night, with all hazards
possible.

By Wednesday night, widespread convection is expected along a SW-to-
NE axis across the OH Vly, including across parts of the ILN FA. The
overall progression of the convection should slow into early
Thursday morning as the parent S/W ejects to the NE, essentially
abandoning its front/boundary in its wake extending to the SW across
the OH Vly. Prolonged and strong moisture and mass convergence along
this stalling/slowing boundary lends itself to a pronounced concern
for the severe potential to transition to a widespread
hydro/flooding setup into early Thursday morning. With PWATs on the
order of 250-300% of seasonal norms (approaching 2") with boundary-
parallel forcing/lift, the potential for training convection with
very heavy rain rates will likely unfold Wednesday night into early
Thursday. It remains to be seen exactly where the greatest hydro
threat will unfold during initial round, but early indications favor
locales near/W of I-71 through Thursday morning before the boundary
slowly pivots to the SE into the day Thursday to near/S of the OH
Rvr.

The problems only continue into Thursday/night as another S/W
digging into the south-central plains will act to further slow the
SE progression of the LL baroclinic zone through the srn OH Vly and
nrn TN VLy, with additional lift generated from continued
moisture/mass convergence along the SW-to-NE axis expected to allow
for nearly-continuous redevelopment of convection across southern
parts of the area, particularly with the arrival of more S/W energy
into Thursday night. The corridor of PWATs in excess of 200%
seasonal norms will remain nearly stationary from Thursday morning
through Friday morning, with additional widespread heavy
rain/flooding likely to unfold across at least parts of the local
area.

After a potential brief respite during the day Friday, yet another
S/W will eject E into the south-central plains Friday night into
Saturday, setting the stage for additional rounds of showers,
storms, and heavy rain locally. Ensemble probs from multiple suites
suggest greater than 70% chance of at least 4" of rain from
Wednesday evening through Saturday night across a large portion of
the region, with the highest probs focusing near the OH Rvr from srn
IL/IN into N KY and SW OH and along/near the OH Rvr. Even after a
potentially significant severe event locally Wednesday into
Wednesday night, the setup for a high-impact/widespread heavy rain
and areal/river flooding event is perhaps even more concerning.

As with any event that affects the region, the details are
incredibly important in determining the locations of greatest
impacts, as well as the scope of those impacts. And that information
will become clearer in the coming days. But confidence is fairly
high in a potentially significant severe (Wed/Wed night) and heavy
rain/flooding event (Wed night through Sat night) to contend with in
the ILN FA through the long term period. These threats will be
highlighted in the HWO.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Northwest winds will continue during the TAF period behind a
departing a cold front. Ceilings in the cold air advection are likely
to continue between 1,000 and 3,000 feet until scattering out late
this evening. VFR conditions will close the period.

OUTLOOK...Showers and thunderstorms will be possible at times
Wednesday and Thursday. MVFR/IFR conditions will be possible at times
Wednesday through Thursday.

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...KC
AVIATION...