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615
FXUS61 KILN 171036
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
636 AM EDT Tue Sep 17 2019

.SYNOPSIS...
High pressure over the Great Lakes will have strong influence
over the weather across the Ohio Valley through the remainder of
the week, keeping dry conditions and comfortable humidity across
the area. However, with very dry ground the temperatures will
continue to run well above normal particularly during the
daytime, with nights remaining much closer to normal. Today
will be the coolest day of the next five, with highs in the
upper 70s to middle 80s, with widespread 80s thereafter. The
next appreciable chance at a more widespread measurable rain
will come later Sunday into Monday as cold front shifts through
the region.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Yesterday`s cold front will be well south/west of the local area
at 12Z this morning, with strong 1023mb high over southeast
Canada. Modest northeasterly low-level flow around this high
will continue a weak backdoor-type low-level cold advection
regime across the forecast area today, making today a little bit
cooler than yesterday, and likely the coolest day of the week.
This morning - GOES RGBs and Fog Product showing eruption of
stratus as the cold advection catches up to a still-moist
boundary layer over Ohio/Indiana. This stratus had been expected
to settle south toward the Ohio River, but recent data has
veered low level wind flow enough that it now appears the
southward progression of stratus will approach I-70 after
sunrise and begin to push more west than south, effectively
stopping the intrusion near/north of Dayton/Columbus.

Once the diurnal heating cycle kicks in, expect this shallow
stratus to begin to mix out on the modest northeasterly breezes,
with the fringes of the stratus lifting into a broken
stratocumulus deck before things become more cellular in nature
late in the morning to early afternoon. For the rest of the
forecast area, a healthy mix of sunshine and fair weather
cumulus with forecast soundings very stable above the boundary
layer during peak heating and precipitable water remaining near
to slightly below normal. Would expect dewpoints /after starting
in the lower 60s this morning/ to mix back into the upper 50s on
afternoon breezes which should make for quite the enjoyable
afternoon.

With late afternoon 925mb temperatures peaking around 18C
/north/ and 21C /south/, expect highs to range from around 80F
in the north and the mid 80s in the south. This is after taking
into consideration the very dry / parched ground which is
helping high temps obliterate the statistical MOS just about
every day for the past week.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Continued very quiet weather over the forecast area as strong
high pressure over southeast Canada continues subsidence and
very dry northeast flow over the Great Lakes. Expect a good
valley fog episode later tonight in the usual spots with the
drier boundary layer airmass allowing lows to drop back into the
50s.

On Wednesday, modification of the low level airmass will
continue under strong insolation and very dry soils. With 925mb
temps rising to 19C /east/ to 22C /west/, this will push high
temperatures well into the 80s area-wide. Would not be surprised
to once again see a rogue 90F reading or two in areas of
northern KY where soils are particularly dry and the warmest low
level thicknesses reside.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A large scale mid level ridge will dominate the weather regime
across the Great Lakes and the Ohio Valley from Wednesday night into
Saturday. The anomalous ridge will keep the forecast dry with high
temperatures averaging much above normal for mid September. As has
been pointed out in previous discussions, model performance with
high temperatures have been poor, perhaps they are not capturing the
very dry conditions that have developed across the region. Thus,
have been starting with a model blend, then raising high
temperatures 3 to 4 degrees, which fits more in line with 925 mb
mixed temperature relationships. This results in highs in the upper
80s to around 90 with lows in the lower to mid 60s.

Aforementioned mid level ridge is expected to become suppressed
during the Sunday/Monday time frame as a mid level trough moves into
the Great Lakes. This should eventually push a slow-moving cold
front southeast into the area. An increase in deep moisture and the
boundary will bring a chance of showers, perhaps a rumble of
thunder, during the Sunday/Monday forecast. Highs in the mid and
upper 80s Sunday should cool into the upper 70s to the lower 80s by
Monday. Lows will remain in the lower to mid 60s.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Stratus has expanded as expected across much of northern Ohio
and is sinking southwest on light northeast flow. Currently have
a well-timed bank of IFR stratus heading toward CMH/LCK with
expected arrival at those two airfields around 13Z if it holds
together. Right now, have not seen any indication that it won`t
so have included a brief TEMPO this morning of IFR ceilings at
both sites, before its forward progress should slow and it
begins to erode on the leading edge owing to heating/mixing.
This should lift the stratus into a broken MVFR deck which
should become more cellular with time as it dissipates. Other
area of stratus well north of KDAY should not impact that
terminal but it is sinking southward somewhat so this will need
to be watched through the morning. Otherwise, valley fog is
plaguing KLUK and this should continue through 13Z before
burning off. Light fog is also possible at KDAY/KILN in before
burning off around 13Z. During the day, expect few-sct cumulus
under sct-bkn cirrus. Mainly clear skies and light winds tonight
with another valley fog event expected at KLUK. Have brought
visibility down after 06Z there with TEMPO to IFR visibility
later in the night toward sunrise.

OUTLOOK...No significant weather expected.

&&

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

&&

$$
SYNOPSIS...Binau
NEAR TERM...Binau
SHORT TERM...Binau
LONG TERM...Hickman
AVIATION...Binau