Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 061708

Area Forecast Discussion
National Weather Service Northern Indiana
1208 PM EST Tue Dec 6 2016

Issued at 1021 AM EST Tue Dec 7 2016

A system will continue to lift northeast through the area today
bringing rain to mainly far northeast Indiana, northwest Ohio, and
portions of south central lower Michigan through mid afternoon.
Conditions will dry out late this afternoon into tonight. Highs
today will range from the mid to upper 30s. Much colder air will
filter into the region behind the system and set the stage for
lake effect snow showers Thursday through Friday night. The more
substantial lake effect snow showers are expected from Thursday
night through late afternoon Friday. High temperatures by Thursday
afternoon are only expected to reach the mid 20s.


Issued at 1021 AM EST Tue Dec 6 2016

Previous forecast remains on track with only minimal changes
needed to account for current PoP trends. Upper level short wave
will continue to lift northeast across Ohio Valley affecting
mainly southeast half of the forecast area. Continued evaporative
cooling/wet bulb processes should keep near sfc wet bulbs high
enough for liquid precip type through the afternoon. Precip should
diminish from west to east during the mid-late afternoon hours.
Only minor tweaks made to highs today with slight downward
adjustment across a few locations.


.SHORT TERM...(Today and Tonight)
Issued at 340 AM EST Tue Dec 6 2016

An upper level system was near Memphis early this morning and was
moving northeast toward the Ohio River. The northwest edge of the
associated deformation zone will move across the forecast area today
and bring a mix of precipitation. A brief wintry mix is possible at
the onset, then the precipitation should become all rain as low
level thermal fields warm. Some brief snow or possibly sleet
accumulations are possible early this morning. Surface pavement
temperatures have dipped below freezing at several locations, so it
is possible there could be brief travel impacts. Precipitation
should end by early evening with skies staying cloudy to mostly


.LONG TERM...(Wednesday through Monday)
Issued at 340 AM EST Tue Dec 6 2016

A cold front will move across the area Thursday, bringing much
colder weather into the weekend. Lake effect snow will develop
Thursday as much colder air spreads over the relatively warm waters
of Lake Michigan.  Delta T values over 20C at 850 mb with a west to
northwest flow will favor snow accumulations over far southwest
Lower Michigan into northwest Indiana. Current thoughts are 5 to 8
inches over these areas near the lake with lesser amounts farther
inland. Lake effect snow will diminish from late Friday into early
Saturday as winds back to the southwest. More snow is expected by
Sunday as a GFS/EC/GEM blend now appears more favorable for
accumulating snow.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1210 PM EST Tue Dec 6 2016

Deeper moisture associated with short wave lifting northeast
across the Ohio Valley will be shunted off to the east over the
next few hours with light rain expected to come to an end at KFWA
around 19Z. Perhaps some brief improvement above 2k feet possible
at KFWA in the mid afternoon hours, but expecting some
deterioration back into the 1-2k ft range late this
afternoon/evening as surface trough axis progresses through the
area. Likewise, should see trend to MVFR at KSBN late this
afternoon in association with this same feature. Broad weak
cyclonic flow and lingering shallow moisture may promote some
patchy drizzle this evening, but will omit from TAFs at this time.
Conditions are expected to improve overnight as low level dry air
advection becomes established behind this trough. West winds of 10
to 15 knots are expected post-sfc trough through this period with
mainly VFR conditions on Wednesday.


LM...Small Craft Advisory from 4 PM this afternoon to 1 PM EST
     Wednesday for LMZ043-046.



SHORT TERM...Skipper
LONG TERM...Skipper

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