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Area forecast discussion 
National Weather Service Indianapolis in
1051 am EST Wed Dec 7 2016

Update...
the aviation section has been updated below.

&&

Synopsis...
issued at 300 am EST Wed Dec 7 2016

Colder air will flow into the area tonight and could bring some
flurries with it. High pressure will then keep dry but cold
conditions into Saturday. A low pressure system will bring a
snow/rain mix Saturday night and Sunday, with another system
bringing more snow chances by Tuesday.

&&

Near term /rest of today/...

Issued at 923 am EST Wed Dec 7 2016

No significant changes made. Radar detecting some snow aloft but
very dry air below snow should keep evaporation occurring and snow
not expected to reach the ground. Current surface observations
show no snow to corroborate this.

Clouds will gradually thicken as the day wears on...but still
expect a few more hours of sun across locations south of I-70.

Still expecting Max temps 35 north where its already cloudy to 40
south.

&&

Short term.../tonight through Friday night/
issued at 300 am EST Wed Dec 7 2016

Models are close enough that the superblend initialization
was accepted for most items.

An upper wave and upper jet will move into the area tonight, and
another reinforcing shot of colder air will also move in. Forcing is
not great, and moisture is limited, especially in the lowest
levels. Thus usually would go with a dry forecast.

However, have seen this kind of colder air squeeze out what limited
moisture is available many times in the past. Thus will have
flurries possible most areas tonight.

The cold air then moves into the area for the remainder of the short
term. Put some flurries in for the extreme northeast forecast area
Thursday night into early Friday as some weak lake enhanced snow
could sneak into the area.

Stayed with a model blend for temperatures. Wind chills in the
single digits will be possible across parts of the area at times
Thursday into Friday.

&&

Long term.../Saturday through Tuesday/
issued at 300 am EST Wed Dec 7 2016

Models are close enough that the superblend initialization
was accepted for most items.

Ensembles in fairly good agreement with the overall weather pattern
during this period, with rather zonal and progressive flow expected.
Main feature continues to be a short wave trough that is progged to
move through the Great Lakes region around Sunday into Monday. There
are still rather large differences with respect to the track of the
associated surface low. Overall, the ensembles are a little farther
south with the surface low track, with the most southern solutions
taking the low through central Indiana.

Will keep pops going in the forecast from Saturday night through
Monday morning to cover this feature. Given the expected track of
the surface low, it appears that enough warm air will get into the
system for mixed precipitation at some point during the event. Will
go with mainly snow Saturday night, with a trend towards mixed
precipitation by Sunday and Sunday night. Precipitation may tend
back towards snow by late Sunday night and early Monday as the
precipitation threat diminishes.
Best threat for accumulating snow looks to be Saturday night into
Sunday morning.

Ensembles suggest another short wave trough may drop into the Great
Lakes by next Tuesday. Will go with chance pops for light snow at
that time.

&&

Aviation /updated kind taf/...

Issued at 1047 am EST Wed Dec 7 2016

VFR through the period. Winds at or below 10 kts through 081500z
then gusting to 20kts after 081500z.

Mid cloud deck around 10000 feet across central Illinois will
progress into central Indiana this afternoon.

&&

Ind watches/warnings/advisories...
none.
&&

$$

Synopsis...50
near term...tucek
short term...50
long term...jas
aviation...tucek

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