Area Forecast Discussion
Issued by NWS Wilmington, OH

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000
FXUS61 KILN 190548
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
148 AM EDT Sat Aug 19 2017

.SYNOPSIS...
An upper level disturbance will move through the region on
Saturday bringing showers and thunderstorms to the region. High
pressure will then be in place for Sunday and Monday. A cold
front will approach the region on Tuesday bringing a return of
precipitation to the area.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A cold front will approach the region from the west tonight. Mid
clouds currently over MO/IL will stream into the Ohio Valley
overnight, and showers with a few thunderstorms will be possible
before daybreak in the northwest underneath a digging H5
trough. Showers and thunderstorms will be advected in from the
west, so there should be ample upstream notice of their specific
time of arrival in the region. A number of models are dry with
this feature, so a hedge to lower pops may be necessary with
future updates. Increased min temps by a degree or two given the
expected cloud cover increasing overnight.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
A decent upper level disturbance will move through the region on
Saturday. The limiting factor with this system will be that
there is not a lot of moisture with this system, however given
the support with this system and model agreement, increased
precipitation chances across northern portions of the region.
Precipitation chances will be less along and south of the Ohio
River. It looks like there will be an initial round of
precipitation that works through the area Saturday morning,
then there will also be the potential for additional
thunderstorm development across extreme eastern portions of the
forecast area with daytime heating during the afternoon. There
is some instability during the day therefore went with a chance
thunderstorm mention as well. Cannot rule out an isolated
damaging wind gust or large hail across extreme eastern portions
of the forecast area with the afternoon development, however
the more likely scenario would be small hail and some gusty
winds.

Went close to conshort for highs which is close to the cool
side of guidance values. With extensive cloud cover expected
with this system and the timing of this system, believe that
most locations will be limited to the upper 70s to low 80s.
Locations along and south of the Ohio River where there will be
less cloud cover and precipitation will see potentially higher
temperatures around the middle 80s.

Winds will pick up during the afternoon as the system begins to
pass through and some wind gusts around 20 mph outside of
thunderstorms will again be possible. Winds will quickly
diminish during the evening hours and cloud cover will begin to
decrease. This will allow for temperatures to drop down into the
upper 50s to low 60s across the area.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Models are in good agreement that a surface high pressure will be
centered over the region Sunday morning. This will bring mostly
sunny skies and seasonable temperatures in the mid to upper 80s.

The center of the high will pull east of the region Sunday night,
allowing a little of a return flow for Monday/Eclipse Day. There
should be some cumulus development in this flow, but the clouds
shouldn`t spoil the viewing. Kept the forecast dry, but there is a
model or two that pops a shower on Monday.

A more substantial chance of rain will develop Tuesday into Tuesday
night as cold front swings through the Great Lakes and Ohio Valley
ahead of a strong H5 s/w. 12Z models are a little slower with the
system on Tuesday, so adjusted the timing back. The best chance of
thunderstorms will looks like Tuesday afternoon into Tuesday night.
Upped PoPs to likely to cover this system.

Behind the front Wednesday, a cooler and drier airmass will begin to
settle in for the later half of the week.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Sharp mid/upper level shortwave trough to pass quickly across
the TAF sites this morning into early afternoon. Little surface
reflection of this system. Currently /06Z/ conditions are VFR
across the sites with increasing cirrus shield over Indiana and
some mid clouds over Illinois where a few showers/storms exist.
Expect this to move across the sites this morning so have VFR
ceilings above 5kft passing across most sites. Kept a VCSH
mention at DAY/ILN/CMH/LCK for a passing sprinkle/shower after
sunrise but overall trend in data over the past 12 hours is for
less activity this morning. Early in the afternoon as the cold
front begins to sharpen up and advance east across central Ohio
expect a band of showers/storms to form likely impacting the
CMH/LCK terminals with a brief potential for MVFR conditions.
Will continue to mention a tempo of VFR showers to indicate the
likelihood of activity, but not go so pessimistic yet until
coverage/intensity is a little more certain. Sites to the
southwest /CVG...LUK...DAY...ILN/ are likely to remain
precipitation free in the afternoon so nothing in the TAFs right
now, though there is some uncertainty on if development can get
far enough west to impact these sites. Right now thinking is
that activity will remain to the east and any broken VFR cigs
will dissipate through the afternoon as flow becomes westerly
and a little gusty, then northwesterly and later toward evening
behind the front. Overnight expect clear skies, and there will
be some potential for fog late in the night so that will need to
be evaluated for the next issuance

OUTLOOK...Thunderstorms are likely on Tuesday into Tuesday
evening.

&&

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

&&

$$
SYNOPSIS...Novak
NEAR TERM...Franks
SHORT TERM...Novak
LONG TERM...Sites
AVIATION...Binau



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