Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 271049

Area Forecast Discussion
National Weather Service Northern Indiana
649 AM EDT Thu Apr 27 2017

Issued at 410 AM EDT Thu Apr 27 2017

A cold front will move across our area today resulting in much
cooler conditions than yesterday with a chance of showers, and
possibly a few thunderstorms east of I69. High pressure will
follow this system across the area tonight providing fair weather
with seasonably cool temperatures.

A strong low pressure system will move slowly northeast from the
southern plains to the Great Lakes over the weekend. As the low
approaches, scattered showers are possible Friday, becoming more
widespread and heavier with some embedded thunderstorms by
Saturday, continuing through Sunday. Windy and cool conditions are
expected early next week as the strong low moves slowly northeast
away from our area.


.SHORT TERM...(Today and Tonight)
Issued at 410 AM EDT Thu Apr 27 2017

Neg tilt shrtwv over MO resulting in cyclogenesis along stalled
cdfnt over IL early this morning. This low will lift north to the
upr Grtlks by 18z with trailing cdfnt sweeping east across our
cwa. Mid level dry slot will overspread our cwa this morning so
while showers still likely during the pre-dawn hours, they become
more doubtful as front moves through this morning. Wk instability
may still support a few tstms over ern portions of the cwa this
morning, but stronger storms should hold off until front moves
east of our area this aftn. CAA should result in steady or slowly
falling temps today, mainly in the 50s west and in the 60s east.

Wk sfc ridge will move across the area tonight providing fair wx.
CAA will transition to WAA overnight as the ridge passes. Some
lingering strato cu into the eve with increasing high clouds
overnight as waa develops and a shearing out shrtwv lifts ne into
the Midwest. Temps expected to bottom out in the m40s.


.LONG TERM...(Friday through Wednesday)
Issued at 410 AM EDT Thu Apr 27 2017

Sct showers psbl in our area Friday as a wk warm front develops
ene into central IN from deepening low over west Texas. This
boundary expected to remain nearly stationary Friday night and
Saturday as srn plains low moves slowly east. Increasing
moisture/instability via strengthening LLJ to the south of the
warm front and east of the low will cause showers to become more
widespread and heavier in this timeframe with tstms becoming more
likely, especially across srn portions of the area. Warm front
expected to lift slowly north across our cwa Saturday night-
Sunday, followed by cdfnt Sunday night. Boundary/baroclinic zone
will linger longest over wrn portion of cwa which should get
heaviest rainfall with 2-3" psbl over the weekend, while 1-2"
expected across the east. These amounts may be sufficient to cause
some flooding problems in our area, mainly on rivers, and will
issue a Hydrologic Outlook to address this concern this morning.
Svr threat with this strong system still looks minimal in our
area. With boundary to the south Saturday, developing wk
instability will be elevated with just the potential for some
small hail. Most of CWA should emerge into the warm sector Sunday
as flow strengthens over the area. Diurnal heating will allow at
least wk sfc based instability to develop in the aftn. Forcing
should be limited in the warm sector Sunday aftn, but if sct tstms
do develop, some could be strong. Instability should wane as the
cdfnt moves through Sunday night, but still may be sufficient
given very strong wind fields to cause some strong wind gusts with
a low topped convective line accompanying the front. Windy and
cooler conditions expected behind the cdfnt Monday as the deep low
lifts slowly ne across the upr grtlks. Some light showers psbl in
the wrap around moisture into early Tue with temps remaining blo
normal. GFS suggests another shrtwv will move out of the srn
plains Wed causing some precip in srn portion of the cwa, while
ECMWF is less amplified with lighter qpf farther south. For now
stayed close to model blend with a low chc south.


.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 643 AM EDT Thu Apr 27 2017

A cold front was just west of the Indiana/Illinois border early
this morning. The front will move through the area early this
morning, bringing showers and eventual MVFR conditions to the
terminals. A thunderstorm is possible in the interim. Subsidence
behind the front should help conditions become VFR by early


LM...Small Craft Advisory until 2 AM EDT Friday for LMZ043-046.




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