-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 211101
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
701 AM EDT Fri Jul 21 2017

.SYNOPSIS...
Multiple disturbances are expected to bring several rounds of
showers and thunderstorms to the region through the weekend and
into Monday. High pressure and dry conditions are then expected
for Tuesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Weak boundary remains just north of the forecast area this
morning. There is an axis of better instability from Illinois
eastward into portions of west central Indiana and into central
Ohio. There is a complex of storms moving into Indiana and also
in advance of this feature isolated showers and thunderstorms in
the axis of the better instability.

Expect the complex to gradually weaken as it moves into the
region, however with favorable airmass in place expect at least
some thunderstorm activity from the complex currently along the
Illinois and Indiana border. With moist airmass in place any
thunderstorm that develops or moves into the region will have
the potential for heavy rainfall.

There is also the potential for some fog across mainly far
northeastern portions of the forecast area early this morning
with some more breaks in the clouds and moist airmass in place.

After this feature moves through this morning expect a lull in
some of the precipitation activity as the atmosphere recovers.
With some breaks in the clouds then expected temperatures are
expected to quickly rebound into the upper 80s to low 90s. With
dewpoints in the 70s, heat index values this afternoon and early
evening hours will be in middle to upper 90s across a large
portion of the region. Near and south of the Ohio River heat
index values are expected to reach the 100 degree mark. Although
there is some question in regards to convective activity and
impact on temperatures, confidence was high enough that decided
to continue the heat advisory across southern portions of the
region.

The system moving through during the morning hours will likely
lay out a boundary for thunderstorm development that is expected
to occur during the afternoon hours and into the evening hours.
Best chance of thunderstorm activity is expected to be across
southwestern portions of the region.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Boundary is forecast to shift northward tonight and therefore
the focus of shower and thunderstorm activity will also be
further north. For tonight and into Saturday went with higher
precipitation chances across the north. Cannot rule out
isolated strong to severe storms with damaging winds and heavy
rain the primary threats Saturday afternoon and early evening.

Heat index values on Saturday will be similar to Friday and will
be highly dependent on convective activity. Will continue to
mention heat in the HWO and monitor for the potential for
additional heat advisory headlines for Saturday, primarily again
across the south.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Good chance that convection will be ongoing at the start of the
period as a surface low moves across the Great Lakes. Storms will
likely translate across the region through the night with some
activity possibly lingering into Sunday. Strong to severe storms may
occur with the greatest potential on Saturday evening when
instability will be the highest.

A cold front will move through the region on Monday with at least a
low chance of some additional storms in the far southern counties.
High pressure will build in Tuesday and Wednesday bringing less
humid conditions. The high will move off to the east by Thursday but
its influence will remain albeit with higher dew points.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
Complex of storms will move into the TAF sites this morning.
Cigs and vsbys will be reduced with this feature especially
across the western TAF sites. After this feature moves through
there will be a lull in the precipitation. If the atmosphere can
recover enough from the morning activity there is the potential
for additional thunderstorm development later today into
tonight.

OUTLOOK...Thunderstorms will be possible at times from Friday
through Monday.
-- End Changed Discussion --

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Heat Advisory from noon today to 7 PM EDT this evening for
     OHZ077>082-088.
KY...Heat Advisory from noon today to 7 PM EDT this evening for
     KYZ089>100.
IN...Heat Advisory from noon today to 7 PM EDT this evening for
     INZ073>075-080.

&&

$$
SYNOPSIS...Novak
NEAR TERM...Novak
SHORT TERM...Novak
LONG TERM...
AVIATION...Novak