Area Forecast Discussion
Issued by NWS Wilmington, OH

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FXUS61 KILN 250115
AFDILN

Area Forecast Discussion
National Weather Service Wilmington OH
915 PM EDT SUN JUL 24 2016

.SYNOPSIS...
A cold front will begin to approach the area overnight and move
through the region on Monday. Hot and humid conditions will be
present in advance of this feature with thunderstorms possible at
times.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
25.00Z KILN sounding revealed an moderate/strongly buoyant airmass
with MLCAPE approaching 2000 j/kg amidst PWAT values of 1.8"+.
However, that`s about it in terms of an environment that will
support severe weather. Low/deep layer flows are weak /0-6km bulk
shears ~20kts/ with even weaker 0-3km shears. DCAPE rather
unimpressive as well below 600 j/kg.

Been watching evolution of storm clusters in nern ILL/nwrn IND
which is being forced by tail end of wrn Great Lakes shortwave
trough and attendant cold front. Storms trying their best to
organize amidst very strong instby out there /where widespread
~80F dwpts are observed/ but lack of shear is leading to poor
organization. Think recent 3-4 runs of HRRR have been generally
grasping what will happen...northern portion of the line near
Gary Indiana will surge southeast and weaken as it approaches the
CWA around 05Z. Central ILL cluster/segment will likely have more
staying power due to feed of better theta-e and approaching MCV to
the west...but net propagation will be slowly southeast such that
this segment will likely never reach sern IND...and if it
does...will have gusted out by then with just a threat for
showers/isold storms.

Going forecast for overnight looks good...given anomalous dwpt
field in place bumped up lows a couple of degrees and slowed rain
chances down just a bit in the west/north overnight but overall
forecast in good shape.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
Heat and humidity will continue for Monday. Heat index values will
be near 100 again with a better chance for this across southern
portions of the region. Continued the heat advisory and excessive
heat warning across southern portions of the region for Monday.

A cold front will move through on Monday. There has been some
variability with how much convection will develop with this
feature, however given airmass in place believe that preciptiation
chances will be likely across the southern portions of the
forecast area by late in the afternoon and early evening hours. A
few of these storms may reach severe limits with damaging winds
the primary threat.

Boundary will hold up across southern portions of the area and
therefore linger preciptiation chances across the far south
through Tuesday night.  With CAA across the northern portions of
the forecast area on Tuesday believe cu will develop during the
day. Even with the CAA expect high temperatures on Tuesday to be
in the middle to upper 80s.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Stationary frontal boundary looks to be positioned along or just
south of the Ohio River Wednesday. Boundary will divide a very moist
air mass to the south from a relatively drier air mass to the north.
Will continue with chance pops for thunderstorms close to and south
of the front on Wednesday.

Boundary will lift north as a warm front late Wednesday night into
Thursday. This will allow precipitable water values to increase
northward, placing the CWA back in a very moist environment for
Thursday.

Models show a shortwave approaching late Thursday or Thursday night.
Timing is still somewhat in question, but there is decent consensus
on the track which will bring it across the Ohio Valley. Therefore,
begin to increase pops for Thursday afternoon and will continue
chance pops into Thursday night for possible influence from
shortwave.

Additional shortwaves may affect the Ohio Valley Friday through
Saturday. Details associated with the shortwaves (such as
track/timing/strength) are in question and will need to be resolved
with time. But the potential for shortwaves combined with a warm
moist air mass means that chance pops for convection will continue
through at least Saturday. Eventually, a cold front may move through
and this could occur late Saturday into Sunday but confidence is low
on the timing of the frontal passage.

Temperatures are forecast to favor near average to slightly above
average values through the long term.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
Isolated/scattered showers and storms which threatened
DAY/ILN/LCK/CMH through early evening have all dissipated leaving
just some sct-bkn high clouds. Attention turns to sct-bkn band of
storms near Chicago which will move southeast toward the TAF sites
overnight...but will likely break up and diminish as it approaches
after about 05Z. Best chance of a shower with decaying cluster
will be at KDAY where a VCSH was added for a few hours overnight.
Otherwise...expect the bulk of this activity to remain west of the
area while being of impact. So the overnight will feature sct-bkn
mid/high cloud as the cloud debris from this complex shifts
downstream over the area. Some light MVFR fog was maintained in
the forecast for LCK/LUK/ILN.

On Monday...cold front will be settling through the area at peak
heating and thus expect storm development to be a little more
robust and higher coverage. Still not enough confidence on
timing/location though to go more than VCTS so that was maintained
in the forecast. Flow will be veering from swly to wly and
eventually nwly across the sites as the front passes.


OUTLOOK...Thunderstorms possible Monday afternoon and again
Thursday.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Heat Advisory until 8 PM EDT Monday for OHZ073-074-078>082-088.
     Excessive Heat Warning until 8 PM EDT Monday for OHZ077.
KY...Heat Advisory until 8 PM EDT Monday for KYZ089>100.
IN...Heat Advisory until 8 PM EDT Monday for INZ075-080.

&&

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



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