Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 121559
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
1059 AM EST Thu Jan 12 2017

.SYNOPSIS...
Issued at 1050 AM EST Thu Jan 12 2017

A cold front moving across the area will cause freezing rain and a
chance of thunderstorms across northwest Indiana and southern
lower Michigan through early afternoon with just rain across the
rest of the area. Conditions will then dry out for the mid and
late afternoon hours. High pressure will move into the Great
Lakes tonight and Friday resulting in dry conditions and
seasonably cold temperatures. Some freezing rain is possible
mainly across southern portions of our area over the weekend as
low pressure moves through the Ohio Valley.

&&

.UPDATE...
Issued at 1052 AM EST Thu Jan 12 2017

Low level frontogenesis forcing immediately behind a cold front
will continue to result in post-frontal precip over the next few
hours before diminishing. Drying mid level profiles through early
afternoon should tend to promote drizzle/freezing drizzle across
far north/northwest through 18Z. With a couple more hours of
freezing drizzle expected, did expand the freezing rain advisory
through 18Z and added a few counties east of the original
advisory. Otherwise heavier rain showers will continue to work
across far northeast Indiana/northwest Ohio through 17Z with an
isolated thunderstorm possible. Some ponding of water on roads and
minor flooding is a possibility across these locations through
early afternoon where storm total rainfall amounts in excess of an
inch are likely.

&&

.SHORT TERM...(Today and Tonight)
Issued at 415 AM EST Thu Jan 12 2017

Main focus on brief icing potential in NW parts of the area this
morning.

Rapid uptick in convective development across western and central
Illinois over the past few hours, as advertised by several of the
hi res models. Stronger cells already producing lightning.
Temperatures overnight have fallen much faster than previously
forecasted (or handled by any model) resulting in increasing
concerns for a period of light icing in far NW parts of the area
in the 11 to 15Z window. Recent mesoscale discussion from SPC
highlights concerns in greater detail. While air temperatures were
on the warmer side yesterday, current temps have likely reduced
any effects of that warming. Given main impacts may occur near the
end of morning commute, opted to issue SPS highlighting concerns
with trends closely monitored over the next hour or 2 for possible
freezing rain advisory. Forward speed of convection could also
allow the activity to get in sooner.

For the remainder of the area this morning, narrow band of
showers has been lingering across SE parts of the area overnight
with SE movement slowed with arrival of next wave moving along the
front. Eventually this should slide east around 12Z and not pose
an issue. Additional showers will also likely move in from
upstream warranting increase in pops through 18Z before rapidly
ending. Temperatures will continue to fall through the morning
and potential does exist for a brief period of freezing rain on
the back edge of the rain as it departs.

Once this wave departs and the main cold front clears the area,
quiet weather will settle for the remainder of the short term
period.

&&

.LONG TERM...(Friday through Wednesday)
Issued at 415 AM EST Thu Jan 12 2017

With main focus on near term, only minor changes to long term with
concerns still lingering over the weekend as series of waves move
along stalled frontal boundary to our south. Impacts Friday night
into Saturday morning still look to be mainly confined south of
US-24 but could edge as far north as US-30 corridor. Mix of snow,
sleet or freezing rain all possible but appear amounts should be
on the light side.

As noted by previous shift greater concern may come Sunday
night/Monday morning and pronounced surge of warmer low level air
rides over cold dome in place initially across the area. All areas
would stand a chance for some sleet or freezing rain that could
cause some impacts to the Monday morning commute. Have continued
mention with trends needing to be monitored in coming forecasts.
By Monday afternoon temperatures should be far enough above
freezing to end any threat. Much like was seen over the past few
days, large temperature variations will occur Monday into Tuesday
NW to SE with many spots climbing into the 40s and also some 50s
the further SE you go. Additional waves will bring chances for
showers through much of the remainder of the period with temps
remaining in the 40s for highs.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 638 AM EST Thu Jan 12 2017

Shrtwv over nrn MO causing an area of showers and tstms over ne
IL/nw IN which should impact sbn this morning. Temps have fallen
below freezing there with caa contg so expect fzra to occur with
some pl during convection. Shra also expected at fwa with ts psbl
but temps should stay above freezing during the precip. Otrws ifr
conditions should cont through the day, becoming vfr this eve as
high pressure ridges into the wrn grtlks.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Freezing Rain Advisory until 1 PM EST /noon CST/ this afternoon
     for INZ003>006-012>014.

MI...Freezing Rain Advisory until 1 PM EST this afternoon for
     MIZ077>081.

OH...NONE.
LM...Small Craft Advisory until 4 PM EST Friday for LMZ043-046.

&&

$$

UPDATE...Marsili
SYNOPSIS...Marsili/JT
SHORT TERM...Fisher
LONG TERM...Fisher
AVIATION...JT


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