ILN issues Area Forecast Discussion (AFD) at May 20, 7:05 PM EDT336
FXUS61 KILN 202305
AFDILN
Area Forecast Discussion
National Weather Service Wilmington OH
705 PM EDT Tue May 20 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 WEDNESDAY MORNING/...
The latest round of showers and thunderstorms will move across
central and southern Ohio and northeast Kentucky through mid
afternoon. This activity is not expected to be severe locally,
however may produce heavy rainfall.
A relative break in convection is expected for a few hours late this
afternoon, before additional showers and thunderstorms develop/move
across the CWA this evening. Much of the CWA is expected to have
convection this evening, however the threat for strong to severe
storms appears to be relegated to the southwest portion of the CWA.
At 18Z, a warm front remains south of the CWA. However, the warm
front is expected to lift northward and areas that wind up south of
the front will be able to realize some surface based instability and
this is where storms could become strong to severe. As mentioned,
this is most likely to occur over southeast Indiana, northern
Kentucky and possibly the extreme southwest corner of Ohio. The main
time frame will be 7 to 11 pm in this area. Strong to damaging winds
would be the primary threat, although large hail or an isolated
tornado can not be ruled out. This activity will also be capable of
high rainfall rates, so localized flooding may also occur in the
heaviest activity.
Convection may linger well into the evening but will decrease after
midnight as the main shortwave advances east. Lows tonight will
range from the mid 50s north to near 60 south.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
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 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 /23Z TUESDAY THROUGH SUNDAY/...
A round of showers/storms continues to lift away from the TAF sites
this evening. A fair amount of VFR conditions have developed in the
wake of the rain with only some patches of MVFR ceilings west of I-
75. VFR conditions at some sites may persist for a few more hours
before chances for showers and storms increases again by 0200z.
Assuming a widespread area of showers/storms does develop as
forecast, MVFR and IFR ceilings likely accompany the area of
precipitation tonight. Widespread shower/storms decrease in coverage
after 0600z with only lower end chances persisting for the rest of
the TAF period. The ceiling forecast is low confidence tonight into
the day on Wednesday. Some guidance is showing lower ceilings holding
on into the day while a good amount of model guidance lifts ceilings
to the VFR category.
Southeasterly winds gradually veer through the TAF period to the
southwest by Wednesday morning and the west by Wednesday afternoon.
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...BPP
SHORT TERM...BPP
LONG TERM...KC
AVIATION...Campbell
Source:
ILN issues Area Forecast Discussion (AFD) at May 20, 7:05 PM EDT---------------
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