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fxus61 Kiln 262330 

Area forecast discussion
National Weather Service Wilmington Ohio
730 PM EDT Mon Jun 26 2017

an upper level trough swinging through the Great Lakes will
bring a chance of showers and thunderstorms this evening and
tonight. High pressure will provide dry weather at midweek with
increasing precipitation chances toward the end of the week as
temperatures warm to near normal.


Near term /until 6 am Tuesday morning/...
shortwave to drop se into the mean trof position over Southern
Lower Michigan this evening. Marginal instby develops late this
afternoon into early evening over west central Ohio. Will
continue to allow very low pop chances into the west late in
the day. Highs again in the lower to mid 70s.

Expect this pcpn axis to drop southeast through iln/S forecast area
tonight and then diminish from the northwest. As marginal
cape diminishes with the loss of heating thunder chances
diminish so will transition to just showers.

Clouds will diminish from the northwest late tonight as surface
high pressure begins to nose into the region. Expect cold lows
to range from near 50 north to the mid 50s south.


Short term /6 am Tuesday morning through Tuesday night/...
precipitation could be lingering in the southeast very early
Tuesday, but will move off to the southeast. In northwest flow
pattern, surface high pressure to build into the region Tuesday.
With cold 800 mb pool over the region expect some shallow high based
cumulus clouds to develop. Tuesday will be dry with rather cool
highs from the lower 70s northeast to the mid 70s southwest.

Surface high pressure to slide east of the region Tuesday night.
Diurnally driven cumulus clouds will give way to clear skies
early Tuesday evening. Expect cool lows from near 50 northeast
to the mid 50s southwest.


Long term /Wednesday through Monday/...
on Wednesday morning, surface high pressure will be centered over
West Virginia, with a relatively dry air mass remaining in place
across the Ohio Valley region. With heights rising, and southerly
flow firmly in place in the low levels, warm advection should be
notable -- with a temperature rise to near 80 degrees.

As a more progressive pattern begins to set up for Thursday and
beyond, mesoscale details will play a significant role in exact
timing and placement of precipitation. A frontal zone is expected to
set up east-to-west across the southern Great Lakes beginning early
Thursday, but despite this, Theta-E and wind plots suggest the iln
County Warning Area will remain in the warm sector (a regime of solid deep-layer
southwesterly flow) through Saturday afternoon. This will tend to
favor convective initiation upstream (north and northwest) of the
iln County Warning Area on Thursday and Friday, with eventual some propagation
downstream which should impact the iln County Warning Area. Pops have been focused
on the northern sections of the cwa, with greater expectations
during diurnal or Post-diurnal time frames (afternoon through
evening / early overnight). A shortwave moving east across Lake
Michigan will provide extra support for convection Friday evening,
but this too seems likely to not land a direct hit on the iln County Warning Area.
It may take until cold frontal progression on Saturday / Saturday
night before chances increase County Warning Area-wide, and pops were increased on
Saturday to reflect this. Through this period, how much of the County Warning Area
remains capped is a question, and mesoscale foci / localized forcing
will help decide if storms can develop within the warm sector. With
ample instability and at least somewhat favorable deep-layer shear,
some heavy rainfall / strong to severe storms could be possible from
Thursday through Saturday. Confidence in any specifics will keep
this out of the severe weather potential statement for now.

With a clearing push behind the cold front late Saturday, models
have trended drier for Sunday, before warm advection begins to bring
a chance of precipitation into the area again on Monday.


Aviation /00z Tuesday through Saturday/...
an embedded upper level disturbance will rotate east across the
southern Great Lakes overnight. As this occurs, a weak frontal
boundary will slip southeast across the terminals this evening
into early morning. There will be a chance of showers, perhaps
an isolated thunderstorm along and ahead of this boundary.
Clouds will decrease in coverage behind frontal passage.

For Tuesday, under northwest flow aloft, scattered cumulus will form
during the heating of the day. Surface high pressure will build
east toward the Ohio Valley through the day, moving across the
Ohio Valley Tuesday night. Diurnal cumulus will gradually
dissipate after 00z, leaving mainly clear skies for the
overnight period.

Outlook...thunderstorms possible Thursday through Saturday.


Iln watches/warnings/advisories...



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