Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 250039

Area Forecast Discussion
National Weather Service Northern Indiana
739 PM EST Tue Jan 24 2017

Issued at 735 PM EST Tue Jan 24 2017

A band of light rain or sprinkles is possible this evening, but
rain chances will increase late tonight into Wednesday morning
across far northern Indiana and southern lower Michigan as a low
pressure system and warm front approach. A lull in the
precipitation chances is expected Wednesday afternoon, but rain
and snow showers are expected to develop Wednesday night before
becoming mainly snow showers late. Some light snow accumulations
of an inch or two are possible across far northern Indiana and
southern lower Michigan with this system. Lows will drop into the
mid 30s tonight before warming into the 40s to near 50 on
Wednesday. For the latter part of the week and into the weekend,
highs will mainly be in the upper 20s to low 30s with a likelihood
of lake effect snow showers.


.SHORT TERM...(This Evening through Wednesday)
Issued at 341 PM EST Tue Jan 24 2017

Shortwave ejecting into Western NE will shear northeast into the
Upper Midwest tonight and the Western Great Lakes by later Wednesday
along the northern periphery of 150 kt upper level jet. Model
guidance has settled in on a nrn MO/se IA to central MI sfc low
track with bulk of the precipitation focused north-northwest of the
IWX CWA near leading baroclinic zone. Still could see a few
periods of rain into nw IN/lower MI later this evening/early
overnight with leading WAA wing, with better chances coming later
tonight into Wednesday morning mainly nw of Hwy 24 as height falls
and corridor of isentropic ascent/fgen lift through. Mid level
dry slot and narrowing warm sector timed for tomorrow
afternoon/evening then brings a brief temp spike well into the
40s to near 50F south...along with mainly dry conditions. Winds
will also veer more southwesterly and increase in warm sector
during this time as low level jet edges through and mixed layer


.LONG TERM...(Wednesday Night through Tuesday)
Issued at 341 PM EST Tue Jan 24 2017

More widespread (mainly light) precipitation still on target to
pivot through later Wednesday night into Thursday morning with
trailing deformation/convergent axis. Cooler air also wraps in
behind sfc low/system cold front allowing any rain to change over to
snow, with areas along/north of US 30 in IN/MI possibly seeing an
inch or two of snow accumulation thanks to lake enhancement.
Moisture/forcing came in a little more impressive with this
feature resulting in slightly higher QPF/SnowAmt when compared to
the prev fcst, though marginal near sfc temps hopefully limits
accums/impacts on area roads into most of Thursday. Moist cyclonic
flow and diurnal component will support somewhat squally/breezy
conditions into Thursday afternoon given moist/cold cyclonic

The rest of the forecast will be characterized by near to slightly
below temperatures and periodic chances for lake effect/enhanced
snow showers as a perturbed west-northeast flow regime takes hold
within a developing Eastern US longwave trough. Delta T`s generally
in the mid-upper teens combined with subtle flow embedded vorts will
likely favor several opportunties for light snow accumulations in
favored wnw flow lake belts through the period.


.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 652 PM EST Tue Jan 24 2017

MVFR cigs in the 1-2k foot range persist across northern Indiana
this evening but improvement is expected later this evening as a low
level warm front approaches the southern Great Lakes region. Band
of light rain associated with strong mid level theta-e gradient
may bring a brief period of sprinkles/light rain to terminals late
evening, but confidence in measurable rain is on the low side. A
period of VFR conditions is expected overnight before primary low
level jet noses into the region toward daybreak. Warm front
extending from mid MS valley low pressure will bring another more
favorable period of light rain Wednesday morning with lower end
MVFR or IFR cigs expected. Moisture axis will quickly shift east
of the area by afternoon with some patchy drizzle possible in mid
level dry slot. After potential morning IFR, generally MVFR
conditions anticipated on Wednesday, possibly improving to VFR
late in the period. Have also maintained LLWS mention for a brief
time early Wednesday morning in association with aforementioned
low level jet.




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

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