Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 091731

Area Forecast Discussion
National Weather Service Northern Indiana
1231 PM EST Fri Dec 9 2016

Issued at 1219 PM EST Fri Dec 9 2016

Dry air has begun to move into the region as high pressure edges
closer and has allowed for the lake effect snow to recede back
towards the lake. Snow is expected to continue for a time closer to
the lake in Northwest Indiana and Southwest Michigan. Then, low
pressure will move northeast from the Southern Plains towards the
region Saturday night and Sunday, and possibly into Monday, with
snow. The snow is expected to change over to rain south of Route
30 before ending. Even colder air comes in behind a cold front
expected to move through around midweek next week.


.SHORT TERM...(Today and Tonight)
Issued at 437 AM EST Fri Dec 9 2016

...Headlines to continue...

Trough was dropping south of the area and allowing a few much more
organized bands to setup as expected. A weaker band has been rather
persistent across NE LaPorte county into portions of St Joseph IN
and Marshall counties where a few inches of snow has likely
accumulated. Further northeast a rather pronounced lake effect band
was oriented from south of Muskegon to north of Kalamazoo and taking
aim on Branch county. In between these additional snow showers were
noted starting to work into the warning area. For the time being
will leave headlines intact with many areas only seeing light
accumulations (South Bend locally seen 1 to 3 inches overnight) with
lesser amounts thus far across the rest of the area. These areas
should catch up into this morning. Also with exact evolution of
these bands still unfolding somewhat any dropping or changes would
be premature for headlines. That being said, will be watching Branch
county closely to see if this main band sits for a while with
potential for 1 to maybe 2 inch per hour rates for 2 to 4 hours
yielding close to warning criteria. Did drop any mention of blowing
snow as wind speeds seem to be just low enough no major blowing of

Have backed off somewhat on duration of weaker lake effect later
today into tonight as flow turns more westerly with time.


.LONG TERM...(Saturday through Thursday)
Issued at 437 AM EST Fri Dec 9 2016

Several inches of snow still look to be in store for parts of the
area starting as early as Saturday evening, but overnight Sat into
much of Sunday and strong low level flow ushers in moist airmass
with soundings showing all snow into late Sunday afternoon. Exact
amounts still need pinning down and are likely to fluctuate until
the energy we will be contending with comes onshore today. Sunday
night, low level temperatures will climb above 0 C across southern
portions of the area, but exactly how warm as well as how far
north the warm air will get remains a point of contention and a
huge issue with regards to precip type. Top down methods bring
just about any precip type depending on final surface temperatures
and low level profiles. Headlines will likely be needed for much
of this period, but will keep out for now given current headlines.

All precip will quickly change to snow and end Monday with some
lingering light lake effect snow showers followed by a brief
breather before much colder air arrives for the area and renewed
potential for lake effect. More on this in later forecasts as models
still varying on magnitude and timing of cold air.


.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1219 PM EST Fri Dec 9 2016

Dry air begins to filter into the region and wind direction changes
to more westerly as the main energy rotates away from the region, so
expecting snow at SBN to slowly recede towards the lakes during in
the first portion of the forecast period. In any snow, CIGs have
been reduced to low MVFR and VIS to IFR so will continue that for as
long as snow continues. Still expecting cloudy skies to continue as
a result of lake instability at both sites, but especially at SBN
where MVFR CIGs are still expected into the early overnight hours.


IN...Winter Weather Advisory until 4 PM EST /3 PM CST/ this afternoon
     for INZ003-004.

MI...Winter Weather Advisory until 4 PM EST this afternoon for MIZ077-

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



LONG TERM...Fisher

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