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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KILN 190211
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
1011 PM EDT Sat Aug 18 2018

.SYNOPSIS...
A weak cold front will slip south of the Ohio River tonight.
Quiet weather is expected on Sunday as high pressure wedges into
the region. The next cold front will move through the area
Monday night and Tuesday, bringing showers and thunderstorms.
Cooler and drier air will settle in behind the front for the
latter part of the week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Convection has waned this evening with the loss of day time
instability. An isolated shower/storm could still occur across
our southeast through midnight, but that should be about it as
a weak cold front continues south. Much of the area will then
see mostly clear skies, except the southeast where stratus may
develop. In addition, much of the region will likely develop
patchy to areas of fog, especially where rain recently fell and
in the typical river valleys. Lows will range from the lower
60s north to the mid/upper 60s south.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Weak surface high pressure will build in from the north with
mid/upper level weakness over the Great Lakes. Fog will improve
quickly early Sunday. Although there will be weak s/w energy
across the north, drier air and surface high pressure should
keep the area dry.

Expect a good amount of sunshine with scattered cumulus
Sunday aftn. Temperatures look to be close to normal with highs
Sunday in the lower and middle 80s.

Surface high pressure to drift east Sunday night with a warm
front developing to our south. Expect mainly clear skies with
an increase in high level moisture toward sunrise. Expect Sunday
nights lows to range from the lower 60s northeast to the upper
60s southwest.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
At the start of the extended forecast period on Monday morning, a
small mid-level ridge will be in place over the Ohio Valley, with
surface high pressure departing to the east off the New England
coast. A generally-progressive mid-level trough will be moving out
of the plains states, heading east across the Ohio Valley through
Tuesday. This will represent the greatest chance for precipitation
through the rest of the forecast, particularly on Monday night ahead
of the initial trough. The timing for the onset of precipitation is
a little bit slower in this forecast on Monday afternoon, but
otherwise the rest of the forecast has not been changed appreciably
for this weather system. The timing change on Monday does allow for
a slightly warmer temperature forecast as well, especially where
warm advection will be maximized over southern Ohio and northeast
Kentucky. Max temps are now expected to range from the lower 80s (NW
CWA) to upper 80s (SE CWA).

In terms of rain and convective potential, showers and storms may be
widespread during the peak of the system on Monday night, with
strengthening low-level moisture convergence and another round of
high precipitable water values (pushing toward 2 inches).
Unfavorable diurnal timing, weak deep-layer shear, and a lack of
focused low-level forcing would suggest the threat for heavy rain
(which looks decent though not outlandish) is greater than the
threat for severe weather (which looks marginal at most).

With the surface cold front lagging the initial trough, and some
evidence of a weak secondary mid-level trough also showing up on the
GFS, PoPs will be held on through Tuesday, with even a slight chance
in the far southeastern ILN CWA into Wednesday. The surface front
will move through some time Tuesday evening into the overnight
hours, bringing cooler temperatures once it does so.

From Wednesday night onward through the rest of the week, dry high
pressure and broad mid-level ridging will remain in place, providing
a fairly quiet forecast -- with temperatures gradually warming from
the mid 70s back into the lower 80s by Friday. Any signal for
precipitation on Saturday on the back side of the high appears very
muted at this point.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
A weak cold front will continue to sag south of the Ohio River
while a weak ridge of high pressure builds in from the north.
Scattered showers/storms should wane this evening with the loss
of day time heating and the movement of the front away from our
area. Mostly clear skies will follow for the terminals. Patchy
to areas of fog will be possible where it rained recently and
where rivers are located. Worst conditions are slated for KLUK
where some locally dense fog will be possible. Other sites will
generally have MVFR visbilities, with some IFR visbilities
possible (KILN and KLCK). KDAY may remain without mist/fog
overnight.

On Sunday, mist/fog will burn off between 12Z and 14Z.
Otherwise, surface high pressure will extend into the Ohio
Valley. FEW cumulus clouds will likely form after 16Z. Winds
will be from the northeast between 5 and 10 knots.

OUTLOOK...Thunderstorms possible Monday night into Tuesday
evening.

&&

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

&&

$$
SYNOPSIS...Hickman/AR
NEAR TERM...Hickman/AR
SHORT TERM...AR
LONG TERM...Hatzos
AVIATION...Hickman