National Weather Service Forecast for: Lancaster, OH Issued by: National Weather Service Wilmington, OH

Updated: 6:24 pm EDT Aug 26, 2026

Thursday Mostly Sunny Friday Sunny Saturday Sunny Sunday Sunny Monday Mostly Sunny Tuesday Mostly Sunny then Slight Chance Showers And T-Storms Wednesday Slight Chance Showers And T-Storms   Hi 81 °F Hi 80 °F Hi 81 °F Hi 85 °F Hi 89 °F Hi 90 °F Hi 88 °F   Tonight Mostly Cloudy then Slight Chance Rain Showers Thursday Night Partly Cloudy Friday Night Mostly Clear Saturday Night Mostly Clear Sunday Night Mostly Clear Monday Night Partly Cloudy Tuesday Night Slight Chance Showers And T-Storms   Lo 63 °F Lo 62 °F Lo 59 °F Lo 60 °F Lo 67 °F Lo 70 °F Lo 71 °F

Forecast from NOAA-NWS for Lancaster, OH.

686
FXUS61 KILN 262312
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
712 PM EDT Wed Aug 26 2026

.WHAT HAS CHANGED...
Added a mention for hot and humid conditions next week.

&&

.KEY MESSAGES...
1) A chance for showers and thunderstorms will develop across the
region this evening into tonight. Another chance for showers and
thunderstorms will develop Thursday afternoon.

2) Hot and humid conditions return next week.

&&

.DISCUSSION...
KEY MESSAGE 1)
Overall trends have stayed on track regarding the forecast tonight.
A weakening line of storms will begin to move into our northwestern
counties across the Miami Valley between 7-9 PM this evening.
Effective shear of 25-30 kts will build into the region later today
with an H5 shortwave ejecting through the Ohio Valley. Additionally,
modest instability around 1500 J/kg will be available near the onset
of thunderstorm activity, but these values will trend lower as we
progress through the evening hours. A few strong to severe storms
remain possible late this evening for portions of the Miami Valley
and southeast IN before storms become more elevated and weaken in
coverage/intensity as they progress southeast. Primary severe threat
will be damaging straight-line winds, with isolated large hail being
a secondary threat.

Surface cold front will slowly progress through the area tonight
which should keep chances for isolated showers/storms around. The
front will be near the I-71 corridor by the mid-moring hours tomorrow
before finally exiting in the late afternoon/early evening. Thus,
additional convection ahead of the front could result in another
round of strong storms, mainly for our far southeast in the lower
Scioto Valley and north-central KY. Thinking that the primary severe
threat will remain east of our CWA, but a couple of our counties may
still get clipped by a stronger storm. Note that an isolated
shower/storm could still develop behind the cold front.


KEY MESSAGE 2)
Longwave ridge will build across a large portion of the eastern and
central CONUS late this weekend and persist through at least the
early part of next week. This will result in an influx of hot and
humid air back into the Ohio Valley, with daytime highs back above
seasonal normals.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
A broken line of SHRA/TSRA will move toward the local terminals after
about 01z, with some uncertainty regarding coverage and intensity
with eastward extent toward 05z and beyond. Have maintained the
PROB30s for TSRA at western sites, with PROB30 SHRA further to the
east for KCMH/KLCK. Brief/sudden changes in VSBY and wind
direction/speed are likely with this activity, but this will be
handled with amendments as needed.

This ISO/SCT activity will taper off by 08z for the local sites,
with some lingering LL moisture near the slow-moving front. Some
MVFR/IFR clouds may develop past about 09z, persisting into mid-
morning, particularly for western sites. There is low confidence on
the development of MVFR/IFR CIGs during this time, with the greatest
potential for CIGs likely to evolve for KDAY/KILN in the several
hours around 12z.

Any MVFR/IFR CIGs by 15z will lift/scatter by 18z, with some very
spotty ISO SHRA/TSRA again possible during the afternoon. However,
due to expected lack of coverage, have kept the fcst dry for now.
SCT/BKN VFR Cu will persist through the afternoon before scattering
out beyond 00z Friday.

Winds will go out of the NW at 5-10kts in the post-frontal
environment, shifting more out of the N late in the period.

OUTLOOK...Thunderstorms possible this afternoon.

&&

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

&&

$$

DISCUSSION...Clark
AVIATION...KC

NWS ILN Office Area Forecast Discussion