Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 110951
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
451 AM EST Sun Dec 11 2016

.SYNOPSIS...
Issued at 447 AM EST Sun Dec 11 2016

Widespread snow will impact the region through this evening,
possibly mixing with rain the further south you may travel. For
additional details check out the latest winter weather product.
Much colder air is still in store for mid week with highs
struggling to reach the teens Wednesday and Thursday and
overnight lows possibly reaching zero or colder.

&&

.SHORT TERM...(Today and Tonight)
Issued at 447 AM EST Sun Dec 11 2016

...First widespread snow event well underway...

Widespread light snow was persisting across the area with occasional
reports indicating many spots have seen anywhere from 2 to 4 inches
of snow thus far. Radar trends suggest a quick cut off in
precipitation taking place across much of central Illinois. Some
concerns that this could work into far S/SW areas this morning and
reduce snowfall amounts somewhat. Renewed fgen band was increasing
returns across much of the western third to half of the forecast
area with visibilities generally 1 to 2 miles. Expecting another
inch or 2 of snow through sunrise in these areas with lesser amounts
east. After 12Z increasing low level jet and much richer air mass
will come screaming northeast in response to the next wave moving
through the Plains. While not overly strong, plenty of lift will
accompany this feature to allow for a rapid expansion and
intensification of precipitation across the area. Confidence in the
warning area remains high that most if not all precipitation will be
in the form of snow, which could become locally heavy at times this
afternoon. At present, saving grace for significantly higher amounts
will be decreasing snow ratios as warmer temperatures arrive in the
column also displacing the dgz from the area of best lift. Even so,
still should see some good bursts of snow with rates of an inch or
more per hour possible. Have trended slightly upward with totals as
QPF continue to increase on all models.

Now for the even tougher part, the advisory area. Main push of
temperatures near/above freezing still looks to remain near/south of
route 24 late afternoon into this evening helping keep snow amounts
in check. However, will be a close call on potential to increase
headlines to a warning 1 tier of counties south depending on how
fast the mix precip arrives and final temperatures. North of 24
grids reflect 4 to 7 inches with locally higher amounts by the time
everything is done, with rapid drop in snow amounts south as snow
rations drop below 10:1. Will defer to day shift for any headline
modifications in the south as only a difference of a degree or 2
could have a large impact.

With regards to tonight, did keep categorical pops lingering through
the evening then a quick taper overnight.

&&

.LONG TERM...(Monday through Saturday)
Issued at 447 AM EST Sun Dec 11 2016


Trough responsible for the messy weather in the short term will exit
to the east with arctic low (around 479 dm) centered west of Hudson
Bay set to pinwheel south and then east along the southern shores of
Hudson Bay by Thursday before exiting into northern Maine Thursday
night. As this transitions south, the well advertised blast of
arctic air will slam into the region starting Monday night and
persisting into Thursday with coldest temps being seen Weds through
Thurs ngt as highs will struggle into the teens (maybe staying in
single digits in some areas) and lows single digits (below zero with
snowpack and clearing??).

Some moderation in temperatures will occur Friday into Saturday as
the next strong system takes shape in the Southern Plains and heads
into the Great Lakes. Lots of variations on track and precip types
with potential for mixed bag of weather for onset followed by
possible period of near/above freezing temps and yet another cold
blast right behind it. GFS/ECMWF in enough agreement to allow
Superblend pops to remain in the high chc to likely range Friday
night into Saturday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1148 PM EST Sat Dec 10 2016

Shrtwv/sfc low movg into the plains late this eve expected to move
to the upr midwest/grtlks by the end of the period. Large area of
snow associated with the theta-e advection out ahead of this system
extended from the Daks to Ohio. Theta-e advection and associated
snowfall expected to persist through this aftn before shifting off
to the east but followed by forcing along the system`s cdfnt
resulting in snow with ifr conditions predominating through the
taf period.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Winter Weather Advisory until 4 AM EST /3 AM CST/ Monday for
     INZ013-015-017-018-020-022>027-032>034.

     Winter Storm Warning until 4 AM EST /3 AM CST/ Monday for
     INZ003>009-012-014-016.

MI...Winter Storm Warning until 4 AM EST Monday for MIZ077>081.

OH...Winter Weather Advisory until 4 AM EST Monday for OHZ004-005-015-
     016-024-025.

     Winter Storm Warning until 4 AM EST Monday for OHZ001-002.

LM...Small Craft Advisory until 4 PM EST Monday for LMZ043-046.

&&

$$

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


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