Area Forecast Discussion
Issued by NWS Northern Indiana

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FXUS63 KIWX 030532
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
132 AM EST Sat Dec 3 2016

.SYNOPSIS...
Issued at 700 PM EST Fri Dec 2 2016

Clouds with just a chance of patchy drizzle with maybe a few snow
flurries mixed in at times will persist through early morning
hours, especially closer to Lake Michigan. Cloudy skies and cool
temperatures will persist into Saturday. Lows tonight will be in
the 30s. Highs on Saturday will only rise a few degrees, mainly in
the middle to upper 30s.

&&

.SHORT TERM...(This Evening through Saturday)
Issued at 259 PM EST Fri Dec 2 2016

Weak surface front combined with moisture flux and weak lake induced
instability off of Lake Michigan leading to persistent light showers
over northern Indiana and lower Michigan. HiRes guidance wants to
actually propagate this narrow corridor of lift and moisture south
through the area this evening. Expect some weakening but will carry
some slight chance pops or sprinkles/drizzle southward based on
observed radar trends at issuance. Otherwise sprinkles/flurries
close to lake tonight.

Persistent widespread cloud cover expected to remain across the
region tonight and Saturday with low level trajectories changing
little through late Sat afternoon before backing ahead of next wave.
Satellite shows only a few breaks and with strong inversion and
cyclonic flow expect this deck to remain in place until Sat evening.
By then...high clouds ahead of Sunday system will be streaming in.
Result will be slightly warmer mins tonight and cooler highs on
Saturday.

&&

.LONG TERM...(Saturday Night through Friday)
Issued at 259 PM EST Fri Dec 2 2016

Still looks to be an active and diverse long term period with
trend toward the coldest air of the young winter season by mid to
late week. Still looking at model differences with details as
expected but much colder with lake effect snow late next week
looking likely.

First short wave to move through Sunday with increased moisture flux
from Gulf of Mexico. This will be a fast moving system with short
but decent burst of pcpn mainly Sunday but possibly lingering into
Sunday evening in the east. Pcpn type looks to be predominately a
wet snow but afternoon timing and marginal boundary layer temps
support some rain mixing in...especially over far southern areas.
Any accums still expected to be minor and mainly on grassy surfaces
with wet bulb temps around 32-34F and warm roads. Snow ratios also
look to be under 10 to 1. Accums will be limited to less than an
inch based on these parameters.

High pressure will follow for later Sunday night into Monday night
with another short period of dry weather. Next piece of energy set
to lift out of southwest CONUS and move through Ohio Valley Tuesday.
12z GFS and ECMWF have come into better agreement but still a lot of
differences in details and fully expect more changes in later runs.
For now best pops with this system look to be over the southeast and
primarily rain with colder air starting to move in behind this
system on Wednesday. Precip type tools do suggest a period of
rain/snow mix possible at onset given evap cooling processes so do
have a period of rain/snow in grids. Stayed close to populated
blends and previous forecast but trend toward much colder with
primarily lake effect snow showers by end of next week. Much too
early for potential lake effect amounts but these trends would
suggest first good lake effect snowfall event of the season if
winds and moisture orient together.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday Morning)
Issued at 132 AM EST Sat Dec 4 2016

No sensible wx concerns this period as moist cyclonic flow remains
entrenched across the Great Lakes. Primarily low end vfr cigs will
dominate but transient high end mvfr cigs again possible invof KSBN
Sat am timed with greater lake based moisture flux within srn
periphery of decaying low level thermal trough.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...Murphy
SHORT TERM...Lashley
LONG TERM...Lashley
AVIATION...T


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