Forecast Discussion - Wilmington, OH
231
FXUS61 KILN 211737
AFDILN
Area Forecast Discussion
National Weather Service Wilmington OH
137 PM EDT Sat Mar 21 2026
.WHAT HAS CHANGED...
No significant changes.
&&
.KEY MESSAGES...
KEY MESSAGE 1) Above normal temperatures will persist until a cold
front moves through the region Sunday afternoon and evening. There
will be a chance of thunderstorms along and behind the front.
KEY MESSAGE 2) Temperatures will briefly return to near normal for
early next week before moderating again by midweek.
Key Message 3) Above normal temperatures are again expected by
Thursday ahead of the next front, which will progress through the
area by Thursday night. Some storms are possible very late Thursday
afternoon through Thursday evening ahead of this front.
&&
.DISCUSSION...
KEY MESSAGE 1) Above normal temperatures will persist until a cold
front moves through the region Sunday afternoon and evening. There
will be a chance of thunderstorms along and behind the front.
NW flow aloft will become a bit more zonal tonight into Sunday as a
/very/ warm airmass advects in ahead of a southward- moving front,
which will be attached to a weak sfc wave translating to the SE into
the interior NE CONUS by Sunday afternoon. The elongated sfc boundary
will stretch from PA to MO by midday, with a tightening pressure
gradient yielding enhanced SW LL flow during the morning/afternoon.
This will help usher in some of the /very/ warm air centered well W
of the OH Vly into the local area during the afternoon, with the
front still positioned just to the N of the ILN FA by mid afternoon.
In fact, if dewpoints are able to mix down into the mid 50s (which
remains a possibility), temps may reach into the mid 80s, challenging
standing local daily record highs for March 22.
There is good support in the guidance that a stout cap will remain
in place in the pre-frontal environment through much of the day,
which should keep storm coverage very limited through the afternoon.
In fact, there is a signal, too, that some of the BL moisture will
be mixed out, owing to diurnally-enhanced deep mixing in the open
warm sector, somewhat limiting SB-instby despite sfc air temps
soaring into the lower to mid 80s. This incremental decrease in LL
moisture, with sfc dewpoints dipping into the mid 50s (opposed to the
lower 60s), will further inhibit/delay CI in the pre-frontal
environment, suggesting that the overall severe potential from the
FROPA could also remain a bit more limited overall. Certainly there
are several environment factors that would point toward a severe
threat -- most notably a robust EML contributing to moderate MLCAPE
in an environment with good LL and deep-layer shear (even though it
is a bit more unidirectional). There is good speed shear through the
column, suggesting a collocation of moderate instby with more-than-
sufficient shear to support storm organization and potential for
supercells and/or linear clusters. However, the environment is only
one piece of the puzzle. It should be noted that the presence (and
persistence) of a robust cap (warm nose within the H8-H7 layer) and
the lack of lift/forcing in the pre-frontal environment adds a
substantial amount of uncertainty to the potential for storm coverage
ahead of/along the front. Overall, do think that the cap holds
through the afternoon and that if storms are able to develop along
the front (and that is a /big/ if), that the best coverage would be
focused near/southeast of I-71 where the best LL convergence will
reside around 22z-00z. The main threats would be large hail and
damaging winds. However, this threat is very conditional, owing to
expected lack of coverage of storms in the more supportive (pre-
frontal) environment (prior to 00z).
There is an expectation, however, for more widespread convection in
the immediate post-frontal environment (00z-06z), but alas that is an
environment which will be increasingly/sharply unsupportive of a
notable severe threat. Suppose there is the potential for brief
(likely small) hail with the stronger (elevated) convection in the
post-frontal environment, but the potential for strong/damaging
winds or a tornadic threat would be zero after the passage of the
front. Do think that the overall severe threat for the local area is
going to be more limited that perhaps originally thought, especially
if the cap is able to hold through the peak heating hours.
Conditions will trend dry area-wide from N to S by 06z as much
cooler/drier air filters in from the N amidst a stiff northerly wind
of 10-20 kts, with gusts to 25kts possible. SW winds of 15-20kts,
with gusts to around 25kts, are expected from mid morning through the
afternoon in the well-mixed warm sector.
KEY MESSAGE 2) Temperatures will briefly return to near normal for
early next week before moderating again by midweek.
Cooler air will filter in Sunday night into early Monday, with highs
on Monday only reaching into the upper 40s to mid 50s from N to S,
respectively. Subfreezing air temps are likely Monday night into
early Tuesday morning, particularly near/north of I-70. Temperatures
will moderate gradually Tuesday into Wednesday, going above normal
again by Thursday ahead of the next front.
Key Message 3) Above normal temperatures are again expected by
Thursday ahead of the next front, which will progress through the
area by Thursday night. Some storms are possible very late Thursday
afternoon through Thursday evening ahead of this front.
A surge of unseasonably warm/moist air will arrive early Thursday
morning, with some showers possible around/prior to daybreak as the
pseudo-warm front moves through the region. This warm airmass will
build into the region during the daytime Thursday before a front
associated with a weak sfc wave translates into the OH Vly by
Thursday evening. This front will provide a focus for widespread
shower/storm activity Thursday evening into early Thursday night
before cooler air again settles back into the region by Friday into
this upcoming weekend.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Aside from a FEW mid/high clouds lingering about, skies have trended
clearer this afternoon. There will be an increase in high clouds past
06z, but otherwise skies will be mainly clear through 18z Sunday.
Light SW flow around 5kts will be maintained through 06z before
gradually increasing into the daytime to 15-20kts, with gusts around
25kts, by the end of the period. WSW LLWS on the order of 40-45kts is
expected between about 08z-14z, particularly for KCMH/KLCK/KDAY. The
period is expected to remain dry, with any pcpn associated with the
front expected to hold off to around 00z Monday.
OUTLOOK...Thunderstorms possible Sunday evening. MVFR CIGs likely Sunday
night into Monday morning.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
DISCUSSION...
AVIATION...
NWS ILN Office Area Forecast Discussion
