Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 142100
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
300 PM CST Sun Jan 14 2018

.SHORT TERM...(This evening through Monday)
ISSUED AT 300 PM CST Sun Jan 14 2018

Light snow associated with increasing warm advection ahead of
a weak short-wave trough has developed across west-central
Illinois this afternoon. 20z/2pm radar imagery and area surface
obs suggest snow is falling along/west of a Galesburg to
Jacksonville line. This is a fairly narrow band of precip, with
the snow coming to an end further west across north-central
Missouri. Based on latest HRRR forecast, it appears the snow band
will spread eastward to the Indiana border by early evening...with
the snow tapering off and perhaps temporarily coming to an end
behind the initial band by mid-evening. Given the current dry
airmass and the transient nature of the band, am expecting little
more than a dusting of snow early this evening. The more
significant snow will not arrive until later tonight as a vigorous
wave over South Dakota dives southeastward into the region. Models
have been fairly consistent with their solutions...bringing a band
of light to moderate snow associated with the second wave and its
associated cold front into the NW KILX CWA late this
evening...then spreading it further east and south overnight. NAM
time-height cross-sections indicate a 3-4 hour window of time when
deep-layer omega is maximized and the highest snowfall rates will
be achieved. Despite moderately strong lift and ample profile
moistening, the progressive nature of this system will limit
snowfall totals. Amounts will generally be on the order of 1 to 3
inches...with the highest totals perhaps close to 4 inches focused
north of the I-74 corridor. The snow will linger across the E/SE
through Monday morning before quickly exiting into Indiana by
afternoon. Will be issuing a Winter Weather Advisory for all of
central and southeast Illinois from 9pm tonight through noon
Monday to cover the accumulating snowfall and the distinct
possibility of blowing/drifting snow Monday morning. Strong W/NW
winds in the wake of the system will bring sharply colder air into
central Illinois...with temperatures falling into the single
digits and teens by afternoon.

&&

.LONG TERM...(Monday night through Sunday)
ISSUED AT 300 PM CST Sun Jan 14 2018

Bitterly cold conditions will prevail Monday night as overnight
lows drop to around zero. Thanks to continued brisk northwesterly
winds, wind-chill values will plunge to between 15 below and 20
below zero. As a result, will be issuing a Wind Chill Advisory for
all of central and southeast Illinois Monday night into Tuesday
morning.

With a sharp upper-level trough rotating through the Great
Lakes/Midwest, cyclonic flow will result in plenty of clouds and
perhaps a few snow flurries Tuesday/Tuesday evening before the
trough axis settles southeastward into the Ohio River Valley.

After that, the very cold weather will persist into Wednesday
before the prevailing upper trough flattens and a pronounced
warming trend develops by the end of the week. High temperatures
will climb into the 30s by Thursday...then will soar into the
upper 40s and lower 50s by Saturday. The next significant
weather-maker will not impact the region until late next weekend
when temps will be warm enough to support rain by Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1147 AM CST Sun Jan 14 2018

A period of very light snow will spread across the area late this
afternoon into the early evening...resulting in slightly reduced
visbys and ceilings gradually lowering to MVFR by 02-03z. Once
this initial wave pushes to the east, there will be a lull in the
precip before the main wave arrives overnight into early Monday
morning. Time-height cross-sections suggest the strongest lift and
thus the heaviest snow will focus on the 08z-11z time frame
before the snow pushes south of the terminals after 12z. Have
included TEMPO groups for IFR ceilings/visbys during this time.
Once the trailing cold front passes, strong/gusty W/NW winds will
develop Monday morning.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 9 PM this evening to noon CST
Monday for ILZ027>031-036>038-040>057-061>063-066>068-071>073.

Wind Chill Advisory from 6 PM Monday to noon CST Tuesday for
ILZ027>031-036>038-040>057-061>063-066>068-071>073.

&&

$$

SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Barnes



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