Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 270755

Area Forecast Discussion
National Weather Service Northern Indiana
355 AM EDT Sat May 27 2017

Issued at 331 AM EDT Sat May 27 2017

A weak high pressure system will move across the area today
providing fair weather. A low pressure system will move northeast
across our area Sunday, likely causing a period of showers and
thunderstorms. This low is expected to intensify and become nearly
stationary over Ontario and the upper Great Lakes early next week
causing cool temperatures and a chance of showers in our area.


.SHORT TERM...(Today and Tonight)
Issued at 331 AM EDT Sat May 27 2017

Scattered showers contg across se portion of cwa along trailing
edge of MCV movg across nrn OH. This convection expected to
move out of the area by 12z. With threat of heavy rainfall
diminishing, have canceled Flash Flood Watch a few hours before
12z expiration.

Upr trof from ND-NV expected to deepen as it moves east to
a MN-KS line by Sunday morning. Fair wx expected today as
upr ridging in advance of this system moves across the cwa.
Diurnal heating should cause low cloudiness this morning
to mix out to a sct-bkn cu deck this aftn allowing for
highs mainly in the m70s.

As upr trof moves east, lee sfc low over se CO/ne NM expected to lift
ne into central IL. Forcing and moisture/instability return along/ahead
of this system`s warm front may cause showers/tstms to spread into
the cwa late tonight. Maintained likely pops across the sw portion of
the cwa for late tonight tapering to slight chc ne, though some concern
pops may be overdone as bulk of high res models suggest a QLCS
will race e-se across the mid MS/lower OH valley`s overnight
disrupting moisture/instability return into our area.


.LONG TERM...(Sunday through Friday)
Issued at 331 AM EDT Sat May 27 2017

Sfc low expected to lift ne across the cwa Sunday with
showers/tstms likely developing/continuing as the warm front
moves through in the morning and a second round psbl in the aftn
along the system`s trailing cdfnt. Aftn pre-frontal CAPE fcst
1500-2500j/kg with 30kt unidirectional deep layer shear and
steep lapse rates suggesting an isolated damaging wind/large hail
threat but wk frontal convergence and capping are sgfnt limiting
factors. Brief heavy rain psbl with any storms Sunday but attm
appears convection will be fairly short-lived at any given
location, so not expecting it to have sgfnt hydro impacts.

Sunday`s sfc low expected to lift n-nw into Ontario with a deep
vertically stacked low forming in this region Monday. This
will result in a cool Memorial Day with a chc of showers/tstms as
a wk shrtwv rotates around the upr low across the wrn Grtlks.
Similar conditions Tue as cyclonic flow and CAA conts, though
prbly cool enough by that time to keep convection sufficiently
shallow to prevent thunder.

Upr low will grdly fill and move east across se Canada Wed-Fri
with sfc high movg through our area. This should provide generally
fair wx through this timeframe, though an isolated shower psbl
with trailing wk shrtwv`s movg across the area. Slow departing
upr trof should allow for a slow moderating trend for temps to close
to normal by late week.


.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 106 AM EDT Sat May 27 2017

Wwd flank of stratocu wedge in wake of intense mcv skirting srn MI
attm will be slow to clear given intense subsidence overspreading
lingering rich boundary layer moisture. Thus will slow ewd
improvement invof KFWA until this aftn. Gist of prior KSBN fcst
holds though and generally followed. Winds aob 10kts this pd.






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