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

Updated: 4:00 am EDT Jul 15, 2025

Today Mostly Sunny Wednesday Chance Showers And T-Storms then Showers And T-Storms Thursday Chance Showers And T-Storms Friday Showers And T-Storms Likely Saturday Showers And T-Storms Likely Sunday Chance Showers And T-Storms Monday Chance Rain Showers then Chance Showers And T-Storms   Hi 88 °F Hi 85 °F Hi 89 °F Hi 82 °F Hi 85 °F Hi 85 °F Hi 85 °F     Tonight Mostly Cloudy then Chance Showers And T-Storms Wednesday Night Showers And T-Storms Thursday Night Showers And T-Storms Friday Night Showers And T-Storms Likely Saturday Night Showers And T-Storms Likely then Chance Showers And T-Storms Sunday Night Showers And T-Storms Likely then Chance Showers And T-Storms Monday Night Chance Showers And T-Storms   Lo 72 °F Lo 72 °F Lo 70 °F Lo 67 °F Lo 70 °F Lo 69 °F Lo 69 °F

Forecast from NOAA-NWS for Lancaster, OH.

245
FXUS61 KILN 150951
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
551 AM EDT Tue Jul 15 2025

.SYNOPSIS...
A frontal boundary will oscillate across the area through the week,
keeping the threat for showers and thunderstorms into the upcoming
weekend. A seasonably warm and humid pattern will continue through
the week as well. The active pattern with numerous rounds of showers
and storms, especially midweek through the weekend, may bring the
potential for heavy rain and flooding to parts of the area.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The earlier ISO SHRA has since dissipated, leaving in its wake mostly
clear skies with just a few Cu and cirrus continuing about the area.
There continues to be a signal for some FG development, particularly
across the lower Scioto Valley into NE KY, but do think that we will
also have some patchy fog in area river valleys and in locales which
were impacted by appreciable rainfall on Monday morning. There is
still some uncertainty in just how widespread/dense this fog may get,
but at least an SPS is probably going to be needed at some point for
a small portion of the local area.

After the fog dissipates this morning, focus will turn to the
approach of a S/W in from the SW through the day. This disturbance is
progressing to the NE along the periphery of the ridge center across
the SE CONUS. With the plenty of moisture supporting moderate to
strong instby, particularly across the Tri-State by early afternoon,
the necessary ingredients should come together to SCT SHRA/TSRA to
once again develop (initially in N KY into the Tri-State before
spreading to the NE by late afternoon into early afternoon). The best
overlap of forcing, instby, moisture should be focused across the
Tri-State through the daytime, so expect that the coverage of
activity will be maximized in these areas. There should be slightly
lower moisture availability (and weaker broad ascent) with NE extent
into the Miami Valley and central OH, so the coverage in these areas
should remain fairly ISO in nature into the evening.

With such a saturated environment, the primary concern is going to be
brief torrential downpours, which will produce 1-2 in/hr rates at
times. This being said, there should be at least /some/ steering-
layer flow, which will help push activity off to the N/NE, likely
limiting the potential for prolonged intense rain rates over one
particular area. But certainly some isolated instances of brief
flooding cannot be ruled out. The overall potential for severe storms
is low, but some gusty winds will be possible with the strongest
cores.

Coverage of SHRA/TSRA will decrease subtly after sunset, but will not
cut off completely as the primary S/W moves into the local area
through daybreak Wednesday. Highs today will top out in the mid 80s
amidst seasonably humid conditions.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
The overnight period is not going to be completely dry as the
best moist ascent overspreads the ILN FA toward daybreak Wednesday.
This should allow for at least SCT SHRA/TSRA to continue to stream
into the area through the night, particularly the Tri-State into EC
IN and the Miami Valley through sunrise. Steering-layer flow
increases a bit more tonight into Wednesday morning, meaning that the
storms should be moving progressively from SW to NE, limiting
prolonged heavy rain over one particular area. However, with PWs
again surging above 150% of seasonal norms, any additional rain in
areas that have already received heavy rain over the past few days
may renew localized flooding concerns as the activity overspreads the
area through the morning Wednesday. Some diurnally-driven
intensification and increase in coverage is expected by 15z,
particularly near/E of I-75, with fairly widespread coverage mid
morning through late afternoon locally.

Additional spotty amounts of 1-2" are expected late tonight through
the day Wednesday, with the concern growing for a cumulative effect
of heavy rain over parts of the area, especially with the prospect of
a /very/ active long term period late week through the weekend.

Lows tonight dip into the lower 70s before rebounding into the mid to
upper 80s Wednesday amidst very humid conditions and scattered to
numerous storms.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
The weak shortwave shifting away from the area to the east means the
local area likely dries out through the rest of Wednesday night.
However, a low pressure moving through the Great Lakes will drag a
cold front southward into the day on Thursday. Quick heating of
surface temperatures Thursday will support thunderstorm development
along and ahead of the front as it slides southward. Widespread
thunderstorms featuring multi-cluster storm mode will support
chances for locally damaging winds and heavy rainfall. As convective
allowing models come in range, the exact area of greatest coverage
will become more clear. Any remnant thunderstorms from
Illinois/Indiana Wednesday night could present lifting mechanisms
ahead of the main front.

This specific uncertainty continues into Friday as the front slowly
drifts south, potentially south of the Ohio River. Some model
guidance has trended farther south with the push southward, and this
will also be influenced by Thursday`s convection. So while PoPs
remain in the likely or higher category across nearly the entire
area Friday (except for northwest Ohio into western Ohio), there is
still an opportunity for much of the activity to be focused
primarily along the Ohio River and south instead of all the way up
to I-70.  Of additional note, temperatures for locations across the
I-70 corridor and north may struggle to get into the 80s.

Confidence remains medium that a break in the convection for much of
the area arrives Friday night and early Saturday. However, the break
doesn`t last long as yet another corridor of deep moisture advects
northeastward into the region from the lower Ohio Valley. They
Friday front moves northeastward, focusing thunderstorm activity
across western & southern locations (eastern Indiana, greater tri-
state and into southern Ohio). While there will be an uptick in
diurnal activity Saturday afternoon, Saturday night may remain
active as thunderstorm complexes move southward out of the lower
Great Lakes.

If remnant thunderstorms do persist through the overnight into the
local area, Sunday`s forecast is a bit more uncertain with the
atmosphere struggling to recover from the widespread cloud cover and
remnant cold-pool air. The subtle ridge begins to build back
northward into early next week, with additional rounds of
thunderstorms forecast with no true break in sight.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
After the BR dissipates at KLUK/KILN by 13z, SCT/BKN VFR Cu will
sprout about area-wide after 15z.

Dry conditions will prevail through the morning before some SCT
SHRA/TSRA develops near KCVG/KLUK by 16z. Additional ISO activity
will spread further to the NE into late afternoon through the evening.
The best coverage is favored near KCVG/KLUK through the daytime,
although some potential for SHRA/TSRA will continue through tonight
as well. Have handled the setup with a TEMPO for KCVG/KLUK and
PROB30s for KDAY/KILN/KCMH/KLCK. Sudden reductions in VSBY and
changes in wind speed/direction will be the primary concerns with
this activity.

Prevailing winds outside of convection will be out of the S at 10kts
or less. Additional ISO/SCT SHRA/TSRA is expected to overspread the
area toward 12z Wednesday and beyond, increasing in coverage after
12z as the activity moves in from the SW. This activity will also
bring with it potential for abrupt changes in VSBY, wind speed, and
wind direction.

OUTLOOK...Thunderstorms are possible each day through Saturday.

&&

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

&&

$$

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

NWS ILN Office Area Forecast Discussion