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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 221845
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
245 PM EDT Tue Aug 22 2017

.SYNOPSIS...
A cold front pushing through the Ohio Valley will bring
organized showers and thunderstorms this afternoon, then drier
and unseasonably cool air filters into the area for the rest of
the workweek. The next appreciable chance for rain after today
looks to be early next workweek.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Several clusters of strong to severe storms continue to track
generally east through the southeastern half of the FA this
afternoon. With this, the axis of instby is also rapidly
shifting eastward and expect that there will not be much in the
way of additional (re)development further upstream (i.e. N/W of
the I-71 corridor). Even if a few cells are able to initiate
along the actual front itself, environment should be worked over
enough to limit svr threat past late-afternoon. With this in
mind, continued to shift highest PoPs earlier and earlier, with
most of the area expected to be dry after 22z (with perhaps a
few lingering light rain showers in the lower Scioto Valley).
Nevertheless, CAMs continue to play catch up with this rapidly
evolving situation, so adjusted PoPs based on radar trends
instead of a particular model solution. The main threat between
now and 21z should be locally damaging winds and large hail,
with the svr threat diminishing past 21z. Although individual
storms will be capable of producing locally heavy rain, the
consistent progression of the storms should limit widespread
flooding issues. If cells are able to train, or move over the
same areas, the local flooding risk may be increased, but think
this would be the exception rather than the rule.

With extensive cloud cover and on-and-off rain showers, think
that the northwest FA has already peaked with their high
temperatures thus far today. With this, there will end up being
a fairly noticeable gradient of high temperatures by day/s end,
ranging from near 90 degrees in the lower Scioto Valley to
around 80 degrees across parts of west-central Ohio.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
A fairly potent cold front will progress through the area early
in the short term period, bringing an end to the seasonably
warm and humid conditions that had settled in the local area.
With the passage of the front will come a wind shift from WSW to
NW, but do not expect much in the way of gustiness with the
FROPA.

As a CAA scheme becomes established in the FA overnight and into
the day on Wednesday, dewpoints will lower and skies should
clear out from NW to SE early tonight. With the increasingly
clear skies and northwest flow, expect lows to range from the
mid 50s in the NW to the lower 60s in the SE.

By Wednesday afternoon, expect a fairly healthy diurnally-driven
Cu field to develop, especially as heights aloft continue to
fall. Some of the global models have been indicating a few very
spotty light rain showers in the northern quarter of the FA
during peak heating on Wednesday afternoon, so did add slight
chance PoPs for a few hours Wednesday afternoon to account for
this potential.

Cu field and any chance for a spotty light rain shower will
diminish towards sunset Wednesday, with a quiet Wednesday night
period expected as surface high pressure begins to nudge into
the western Ohio Valley. Lows on Wednesday night will dip into
the lower to mid 50s area-wide.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
A weak upper level disturbance will bring an increase in cloud cover
and an isolated shower potential to central Ohio on Thursday.  CAA
will also lead to an extensive cu field.  Dry conditions will return
by Thursday evening and then expect dry conditions through the
weekend.  High temperatures through the weekend will be in the 70s
with lows in the upper 40s to the middle 50s.  A slight chance of
thunderstorms will be possible Monday and Tuesday with a weak
disturbance.  This system continues to slow down and be weaker than
previous runs.

&&

.AVIATION /18Z TUESDAY THROUGH MONDAY/...
Convective activity starting to come together for the afternoon
hours with main time frame to impact terminals within the first
hour or so of the valid TAF period before activity slides east
of the local terminal corridor. Did include TEMPO VSBY and CIG
restrictions, especially for eastern terminals of KCMH and KLCK
where activity will be slowest to clear.

Nevertheless, main convective lines will be east of terminals by
21z or so, with just some lingering -SHRA for an hour or two
past that. By this evening, VFR conditions are expected area-
wide with a veering of winds from WSW to NW past 03z. Light
winds will prevail overnight but should stay up enough to
prevent widespread BR. This being said, did add a TEMPO MVFR
VSBY restriction at KLUK around sunrise Wednesday, despite
unfavorable wind direction.

Past 12z Wednesday, some diurnally driven VFR Cu will likely
develop as CAA scheme becomes established in the area. Cannot
completely rule out an isolated -SHRA for northern terminals
towards very end of period, but isolated nature of coverage and
lack of confidence precluded inclusion for right now.

OUTLOOK...No significant weather.

&&

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

&&

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