Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 161156

Area Forecast Discussion
National Weather Service Northern Indiana
656 AM EST Thu Nov 16 2017

Issued at 652 AM EST Thu Nov 16 2017

Cold and blustery this morning before winds diminish this afternoon
and high pressure builds in. High temperatures will claw back to
around 40 this afternoon. Another potent and moisture laden storm
system will move through the region Friday night and Saturday
with periods of rain, wind, and milder temperatures expected.


.SHORT TERM...(Today and Tonight)
Issued at 337 AM EST Thu Nov 16 2017

Sfc ridge centered over nw MO will build ewd into sw IN by evening.
Vigorous but brief cold advection wing wrapping ewd south of upper
trough spinning through cntrl MI failing to foster any sig lake
response other than filling with stratocu. Thus highly doubt any
measurable precip in the offing later this morning this far south
given sharp frontal inversion seen in upstream 00Z raob out of DVN
and have dropped prior mention entirely across the far n/nw.

Otherwise sfc ridge continues east into the ern OH valley by Fri
morning with broad return flow warm advection ramping late which
will keep low clouds in place and stave off an even colder overnight.


.LONG TERM...(Friday through Wednesday)
Issued at 337 AM EST Thu Nov 16 2017

Warm sector gradually deepens Fri ahead of developing sfc cyclone
ovr wrn KS. Slower concensus ejection of this system into the lakes
Saturday warrants some contraction in pops Fri aftn. Otherwise gist
of prior fcst remains on track as system rapidly deepens overnight

Primary uncertainty is nwd progression and eventual stall of low
level baroclinic zone which will serve as the pathway for sfc
cyclone track with as yet enough spread to limit additional qpf
detail. Nonetheless sig warm sector moisture flux with some modified
gomex influence into baroclinic zone points to some locally heavy
rainfall possible through parts of the area. In addition H85 based
theta-e ridging favors bona-fide thunder risk as well which if
realized will augment heavy rain risk higher. However rapid
northeast progression of upper trough looks to preclude a sig flood

Brief but robust cold advection wing follows for a time late Sat
night/Sun morning. Per H85 based thermal trough aoa -10C would
expect some lake response esp through sw MI and will bump
appreciably higher over subdued blend. However boundary layer temps
appear too warm for snow.

Thereafter brief warm advection in wake of weekend system for Mon
followed by a general cooldown through Thu as a series of low
amplitude nrn stream disturbances amplify ewd through srn Canada and
reinforce sfc ridging across the lakes/OH valley.


.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 652 AM EST Thu Nov 16 2017

The cold front has made its way through our forecast area, and it
looks like ceilings have lifted to around 2000-2500 ft, which puts
us towards the upper tier of MVFR. Expect ceiling heights to remain
at this level until later today, where we see an improvement to VFR.
Some of the guidance suggests a drop to MVFR later tonight again as
inversion heights lower, but for now went optimistic with the latter
part of the period. Otherwise, expect decreasing west-northwest winds
throughout the day, becoming light and somewhat variable after


LM...Small Craft Advisory until 7 PM EST this evening for LMZ043-046.




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