ILN issues Area Forecast Discussion (AFD) at May 21, 2:43 AM EDT765
FXUS61 KILN 210643
AFDILN
Area Forecast Discussion
National Weather Service Wilmington OH
243 AM EDT Wed May 21 2025
.SYNOPSIS...
A warm front will approach the Ohio River this afternoon with low
pressure tracking across the area tonight into Wednesday. This will
bring showers and thunderstorms to the region. A large upper level
low dropping southeast across the Great Lakes will keep cool and
unsettled conditions in the forecast for the latter part of the week.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Two areas of showers and storms will move through this evening as a
warm front remains along and north of the Ohio River. The southern
cluster of showers and storms is just south of the warm front with
the main bulk of convection remaining well into central and southern
Kentucky. Only some stratiform precipitation and with a few
convective elements will move east through northern Kentucky and
parts of southern Ohio this evening. The severe threat looks to
remain very low give the mostly stratiform nature of the rainfall.
The second area of showers and storms that is forming along the warm
front in Indiana will likely progress eastward into Ohio this
evening. This precipitation has featured more convective elements
compared to the rain moving into northern Kentucky which suggests an
isolated severe threat is possible. Additionally, these storms have
exhibited some rotation aloft at times. Hail would be the main
threat if storms hold together as these storms are north of the warm
front, although a wind threat cannot be ruled out of storms remain
strong.
These two areas of showers and storms move east after midnight with
just lower end shower chances remaining through the early morning.
Forecast lows are in the upper 50s.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
Upper trough will be located over the Great Lakes and Ohio Valley
Wednesday/Wednesday night, with a surface low moving into
Pennsylvania. Trough will keep plenty of clouds along with some
showers across the CWA. Highest coverage will be
over the northern CWA. Isolated thunderstorms with weak instability
will also be possible Wednesday afternoon. Wednesday will be another
cool day, with highs generally in the 60s, and lows Wednesday night
ranging from the upper 40s to lower 50s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The long term period will be characterized by below normal temps and
periodic chances for showers, with the overall potential for
hazardous weather looking quite low into early next week.
An expansive mid/upper level low will churn about the ern Great
Lakes into the northeast CONUS for the end of the workweek, with
cool cyclonic flow being maintained over the OH Vly through this
time. As several vorticity lobes pinwheel around the larger-scale
low center, episodes of light SHRA is expected locally, with some
diurnal enhancement expected Thursday afternoon. Very cool temps
aloft will support steep lapse rates, which may support the
development of some low-end instby on Thursday afternoon/evening.
Nevertheless, SCT to numerous SHRA are expected during the daytime
Thursday before becoming more ISO in nature by night into the day
Friday.
More light SHRA can be expected on Friday, although perhaps with a
bit less coverage and further E into central OH than will be the
case on Thursday. Either way, both Thursday and Friday look to be
cool days area-wide, with a few SHRA lingering on Friday in ern
parts of the local area. Temps will generally be about 10-12 degrees
below seasonal norms for the end of the workweek, with lows in the
lower to mid 40s and highs in the lower 60s. The maintenance of some
light NW sfc flow and fairly expansive cloud cover should inhibit
frost potential, despite chilly air temps during the nighttime.
Drier conditions are expected on Saturday as the stacked low lumbers
off to the E, with NW flow becoming established in the OH Vly into
early this weekend. Highs on Saturday will be warmer, but still
below seasonal norms, topping out in the mid to upper 60s with a mix
of sun and clouds.
Into Sunday and early next week, a very similar pattern to what we
just emerged from looks likely to set up, with large-scale negative
height anomalies in the NE CONUS stretching back to the W through
the Great Lakes as zonal flow becomes established from the mid MS
Rvr Vly through the srn OH Vly. As S/W energy pivots to the SE from
the upper Midwest into the south-central plains by Sunday/Monday,
another quasi-zonal baroclinic zone will tighten, providing a focus
for several rounds of SHRA/TSRA activity during this time from the
central plains into the srn OH Vly and TN Vly. The latitudinal
placement of this front will ultimately dictate which areas remain
dry and which ones will be susceptible to episodic storm chances
Sunday through much of early next week. Right now, ensemble guidance
supports this axis to initially become established across the srn
quarter of the ILN FA (and points southward), which would keep most
spots near/N of I-70 dry through Monday. But this is far from
certain, and therefore chance PoPs will be maintained, especially
near/S of the OH Rvr, for the latter part of the long term period
given the uncertainty in where this boundary of repeated storm
activity will ultimately set up. This being said, it does appear
that better rain/storm chances may try to nudge a bit further N into
the local area by Monday/Monday night as the weak/occluded sfc low
drifts to the E into the mid MS Rvr Vly, but the details of this
will come into better focus in the coming days.
A slow warming trend is expected Sunday into early next week, but
temps should generally remain below normal through the entirety of
the long term period.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Mid level low to pivot east through the southern Great Lakes
today/tonight. Showers with embedded thunderstorms have shifted
northeast of the TAF sites. Expect ceilings to drop thru MVFR with a
period of IFR ceilings possible toward sunrise into early Wednesday.
Shower chances decrease overnight into early Wednesday but can not
rule out a stray shower. Shower chances increase Wednesday afternoon
as the 5H low approaches the area. Some marginal instability develops
across the east and therefore a brief window exists for a
thunderstorm over KCMH and KLCK. Ceilings lift thru MVFR with VFR
conditions returning during the afternoon. The VFR conditions will be
replaced by a return to MVFR this evening as clouds lower.
Southeasterly winds at 5 to 10 kts veer southwest this morning and
the west by Wednesday afternoon. As the gradient tightens this
afternoon expect winds to increase with sustained winds around 15 kts
with gusts up to 28 kts at times into early evening.
OUTLOOK...MVFR ceilings and visibilities are possible Wednesday
night and Thursday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...BPP
NEAR TERM...Campbell
SHORT TERM...BPP
LONG TERM...KC
AVIATION...AR
Source:
ILN issues Area Forecast Discussion (AFD) at May 21, 2:43 AM EDT---------------
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