Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 100551

Area Forecast Discussion
National Weather Service Northern Indiana
1251 AM EST Sun Dec 10 2017

Issued at 1245 AM EST Sun Dec 10 2017

Light snow will gradually diminish by early morning as it moves
eastward, mainly impacting areas along and east of I 69.
Otherwise, expect mostly dry conditions today. A few flurries are
possible north of I 80-90 late this afternoon, but no accumulation
is expected. Highs will climb into the upper 20s and low 30s. Another
Alberta clipper will bring renewed snow and lake effect snow
chances Monday afternoon through Tuesday.


.SHORT TERM...(This Afternoon through Sunday)
Issued at 150 PM EST Sat Dec 9 2017

Heavy lake enhanced/effect snow will remain the story well inland
into the evening hours. A classic type 6 MESOVORT, no doubt
enhanced under the synoptic scale sfc reflection this morning, has
worked inland into north-central IN as of 1830z. Whiteout
conditions and 1-2"/hr snowfall rates have been observed with this
feature. The hope is for this mesovort and snowfall rates/impacts
to weaken some as it tracks toward or just southwest of the Fort
Wayne area within the next few hours. Will cover with a SPS if
needed. Otherwise the main focus is turning to the developing
dominate single band in areas under warnings and advisories.
Radar/satellite show the main convergent axis along the long axis
of Lake MI with another separate band southwest from near Muskegon
MI. Strong low level flow will force this band well
inland...mainly west of US 31 this afternoon...then gradually
shifting east and weakening a bit with time to the US 31 corridor
early evening and to or just west of Hwy 15/US 131 mid evening.
Whiteout conditions/1-2" per hour rates/blowing snow can be
expected within this band.

Only a few leftover light snow showers or flurries off the lake
then by later tonight into Sunday morning as backing
winds/drying/subsidence take a toll on inversion heights. The next
weak/trailing pv filament and associated subtle sfc trough swings
through later Sunday afternoon/early evening. This weak forcing
coupled with some lake enhancement could be enough to generate a
few light snow showers or flurries mainly north of US 20 in far
nrn IN/lower MI.


.LONG TERM...(Sunday Night through Saturday)
Issued at 225 PM EST Sat Dec 9 2017

Perturbed/cold northwest flow will persist into next week as several
clipper systems ripple through bringing snow chances and reinforcing
shots of cold air. The first system to watch will be Monday into
Tuesday as shortwave and attendant sfc low take a track east
through the Lower Great Lakes by Monday aftn/eve...then deepening
a bit into the Eastern Great Lakes by early Tuesday given some
phasing with a trailing pv anomaly. Model trends today have been a
little farther south with leading WAA/isentropic snow (1-3"?)
Monday into Monday evening, best chances still north of US 30. CAA
wing then wraps in later Monday night into Tuesday with colder
temps and another round of LES. LES and additional chances for
weak clipper systems will result in additional more light snow
chances mid-late week. Eastern conus troughing does look to relax
by next weekend. This could result in a decent, yet brief, warmup
into Saturday and possibly Sunday.


.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1245 AM EST Sun Dec 10 2017

Expect gradual improvement at the TAF sites as surface low pressure
drifts further eastward and flow amplifies into a more zonal pattern
aloft. Lingering light snow at KFWA will diminish within the next
hour, though the potential for a BKN025 deck remains through
probably 8z. Beyond that, expect VFR conditions to prevail through
the remainder of the period. KSBN will return to a period of high-
end MVFR ceilings this evening as a shortwave ripples through aloft
and a surface trough enters from the west. A few flurries are
possible, but will bring little to no impact to the terminal thus
left any snow mention out of the KSBN TAF for this issuance.


LM...Small Craft Advisory until 10 PM EST this evening for LMZ043-046.



SHORT TERM...Steinwedel
LONG TERM...Steinwedel

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