339
FXUS61 KILN 201107
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
707 AM EDT Sun Jul 20 2025

.SYNOPSIS...
Multiple rounds of thunderstorms will bring the potential for
damaging winds and isolated tornadoes this afternoon into tonight
and flash flooding through Monday morning. Heat will start to build
later in the week.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...
Key messages and concerns for today are the flash flood threat and
also the severe threat across the region with a focus on south of
Interstate 70. Damaging winds, isolated tornadoes, and flash flooding
will be possible. A flash flood watch is in effect for a large
portion of the region to account for the heavy rain threat. Heat
index values near 100 will also be possible near and south of the
Ohio River.

Overnight, generally just expect some light shower activity. Stratus
is already starting to work eastward through the region. Not
expecting the fog to be as thick overnight, however have patchy fog
mention in the forecast across western portions of the region.

For the day today there is the potential for some isolated to
scattered shower and thunderstorm activity in the morning, however
the main focus for severe weather is during the afternoon and into
the evening hours. There are concerns as mentioned with damaging
winds, tornadoes, and flash flooding. Have mention of these threats
in the HWO and also have a flash flood watch out for all except the
northern portions of the region. There is some question on the
northern extent and confidence is lower in the northern tier of
counties in the flood watch, but high enough for the watch.

Forecast heat index values are expected to be near 100 near and south
of the Ohio River. Confidence was not high enough to mention this in
the HWO or to issue an advisory however, given convective potential
and potential blow off from storms. Will have to monitor to see if
convection holds off enough on Sunday that further messaging is
needed about heat.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM MONDAY/...
There will be a decrease in activity after the first main area of
storms, however there will be another round that starts to move into
the area quickly following the first round. This will be especially
concerning for flash flooding due to rainfall being at night and also
due to the previous expected rainfall as well. This will move
through, however precipitation will not be over. Some locations near
and south of the Ohio River will have rain continue through the
overnight hours and into Monday as well. Northern portions of the
flash flood watch might have a longer time on them than is necessary,
however given the several rounds of rainfall, decided just to have
the one end time on the flash flood watch.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Surface high pressure will move east across the Great Lakes Monday
night into Tuesday and be centered over New England Tuesday night
into Wednesday. Surface winds on the back side of the high will begin
to bring deeper moisture back into the CWA Wednesday. Temperatures
will trend a touch below normal under the high, then warm back to
above normal levels beginning Wednesday. Main concern during this
time is heat, particularly for Thursday and Friday. The national
blend of models continues to predict anomalously high dewpoints for
these two days. With temperatures around 90 and dewpoints in the
middle to upper 70s, the heat index would reach above 100 degrees.
Will mention this potential hazard in the extended portion of the
HWO.

Mid-level ridging over the Ohio Valley on Thursday will begin to
flatten some on Friday. Signal in the guidance is perhaps a slow-
moving boundary begins to sag south into the Great Lakes at this
time. The front could help to provide a better chance of showers and
storms starting Friday... though confidence at this time range is
low.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Complex aviation setup with stratus moving across the TAF sites this
morning. Cigs will increase some during the day today, however MVFR
cigs will be possible with some of the thunderstorm activity. Timed
in two main areas of thunderstorms that are likely to move into the
TAF sites through the TAF period. Outside of those times, showers and
isolated thunderstorms will still be possible at times. Best chance
for gusty winds with the storms will be KILN, KCVG, KLUK, and KDAY.
Will likely need to adjust these gusts with times as confidence
increase in thunderstorm timing.

OUTLOOK...Thunderstorms are possible through Monday and then again on
Thursday. MVFR ceilings and visibilities are possible into Monday.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Flood Watch from 1 PM EDT this afternoon through Monday morning for
     OHZ042-051-053>055-060>065-070>074-077>082-088.
KY...Flood Watch from 1 PM EDT this afternoon through Monday morning for
     KYZ089>100.
IN...Flood Watch from 1 PM EDT this afternoon through Monday morning for
     INZ050-058-059-066-073>075-080.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...