Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 182327
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
727 PM EDT Mon Sep 18 2017

.SYNOPSIS...
Issued at 716 PM EDT Mon Sep 18 2017

A weak cold front will linger over north central Indiana and Ohio
this evening keeping a slight chance for showers and an isolated
thunderstorm in the forecast. A stronger system will approach
overnight into Tuesday and will likely bring more widespread
showers and isolated thunderstorms to much of the region. High
pressure then moves back in for Wednesday through the weekend with
dry conditions and unseasonably warm temperatures well into the
80s.

&&

.SHORT TERM...(Late This Afternoon through Tuesday)
Issued at 227 PM EDT Mon Sep 18 2017

A weak front has stalled out just south of US 24 this afternoon and
will remain in place into this evening. There may be just enough
diurnal heating/instability to pop a few showers/storms here,
though weak convergence/forcing should limit coverage to iso-sct at
best. Warm and dry otherwise into this evening on the southern
fringe of high pressure shifting east through the Western/Northern
Great Lakes.

Rain chances increase later tonight into Tuesday morning as mid
level shortwave over the Central Plains lifts northeast through the
OH Valley and Great Lakes. Showers and perhaps a few rumbles of
thunder (thanks to some elevated instability) should tend to focus
along the returning/aforementioned frontal zone under weak upper
divergence/height falls aloft. Bumped up QPF/PoPs a bit during this
time across the entire forecast area given good moisture return and
modest forcing. Shower coverage should wane from sw to ne later in
the morning/early afternoon in wake of the upper wave and deeper
moisture. However, similar to today, there could be some iso-sct
redevelopment during the afternoon near the leftover frontal
boundary as any filtered sunshine allows boundary layer to become
at least marginally unstable.

&&

.LONG TERM...(Tuesday Night through Monday)
Issued at 227 PM EDT Mon Sep 18 2017

A 588 dm plus upper ridge will build over the region mid week
through next weekend supporting unseasonably warm and mainly dry
conditions. The only low chance for showers appears to be later
Wednesday night/early Thursday into nw IN/sw Lower MI as a decaying
line of showers attempts to survive east into the building ridge.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 716 PM EDT Mon Sep 18 2017

VFR conditions this evening but an upper level wave will bring
showers and an isolated tsra back into the region overnight into
Tuesday. Tsra chances too small to include at this time for point
forecasts but could see introduction with 06z TAFs as
precipitation nears and radar/lightning trends dictate when and
where best chances will occur. Cigs and vis expected to drop into
MVFR range after 06z with IFR a good possibility as rain arrives
after 09z. Conditions expected to slowly improve Tuesday
afternoon with return to VFR.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...Lashley
SHORT TERM...Steinwedel
LONG TERM...Steinwedel
AVIATION...Lashley


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