Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 242041

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

Issued at 1221 PM EST Tue Jan 24 2017

A low pressure system passes by to the north allowing for a
chance for light rain especially west of US-31 and north of US-6
later tonight into Wednesday. As a cold front moves through
Wednesday night with more seasonably cool temperatures, any rain
will be able to change to snow. 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 allowing for the possibility
of lake enhanced 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 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1221 PM EST Tue Jan 24 2017

High pressure ridge moving in allows some low level dry air to raise
the CIGs to MVFR level. CIGs will drop again towards morning hours
Wednesday with the moistening of the column as a result of the
approaching low pressure system from the southwest. Enough dry air
nearby may keep FWA mostly dry Wed, but can`t totally rule out a
shower midmorning. SBN has a better chance at showers with the
low closer and therefore a more moist column. With the incoming
low level jet, have indicated the backing winds overnight and
added a few hours of shear at both sites.




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

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