Area Forecast Discussion
Issued by NWS Central Illinois

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033
FXUS63 KILX 151748
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1148 AM CST Mon Jan 15 2018

.UPDATE...
Issued at 958 AM CST Mon Jan 15 2018

15z/9am surface analysis shows a strong cold front approaching the
I-57 corridor...with most of the accumulating snow associated with
the boundary now off to the east in Indiana. The exception is
across the far SE KILX CWA along/southeast of a Robinson to Olney
line where light snow lingers. Behind the front, windy and sharply
colder conditions are noted with off-and-on snow flurries.
Temperatures are currently in the lower to middle 20s across east-
central Illinois, but quickly drop into the single digits after
FROPA. Some clearing is working into the southwest CWA:
however, clouds poised to the northwest across Iowa will pivot
back into the area and additional diurnal clouds will develop as
well. End result, will be a partly to mostly cloudy and cold
afternoon. Wind-chill readings will drop below zero everywhere
except south of the I-70 corridor by mid to late afternoon.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 350 AM CST Mon Jan 15 2018

The 2nd wave of light snow moved east across central IL past few
hours with back edge of this light snow over western central IL.
The heaviest snows are now east of Peoria and Springfield and
extending east to along I-57. Snowfall amounts from 1st warm air
advection band of light snow late Sunday afternoon and evening
ranged from a half to 2 inches. The 2nd wave should bring another
half to 2 inches as it diminish from west to east during this
morning, giving a storm total of 1-4 inches by noon. Scattered
flurries will linger into the afternoon east of the IL river.
Will continue the winter wx advisory this morning across CWA,
though will likely be able to cancel western counties around
sunrise, and possibly central counties by mid morning. Brisk
south winds early this morning to switch WNW during the morning
and cause some blowing snow.

09Z/3 am surface map has 1020 mb clipper low pressure over sw WI
with its arctic cold front approaching nw IL and extending into
central MO. 00Z forecast hi res models take low pressure to near
Chicago by 18z/noon today while sweeping the arctic cold front
east across central IL and reaching the IN border by lunch time.
Brisk south winds ahead of the front will switch WNW behind the
front and gust in the 20s. Highs will be reached early this
morning over western/nw CWA where current readings there in the
low to mid 20s will fall through the teens during this morning and
continue to fall through the single digits during the afternoon.
Highs will reach the mid to upper 20s this morning over eastern/se
IL then fall into the 5-10F range by 5 pm.

Will continue the wind chill advisory across CWA tonight into Tue
morning for wind chills of 15 to 25 below zero. Lows tonight range
from -3 to 2 above zero, with brisk wnw winds continue much of the
night. A strong 523 dm 500 mb low spinning over ne MN will weaken
a bit to 530 dm as it moves over southern Lake MI by dawn Tue.
This will pivot a strong upper level trof se into nw half of IL
overnight and to bring some flurries to central IL overnight.

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 350 AM CST Mon Jan 15 2018

The strong upper level trof continues to pivot se into heart of IL
by midday Tue and then east over NW OH, IN and mid MS river valley
by mid Tue night. This will bring mostly cloudy skies Tue, and
gradually shift chances of flurries se across central and
southeast IL Tue and linger east of I-57 into Tue evening. Lake
effect snow band from Lake MI should stay ne of Danville. Highs
only in the mid teens Tue and temps, with wind chills still 5
below to 5 above zero mid Tue afternoon. Another frigid night Tue
night with lows zero to 5 above, and lighter WNW winds should keep
wind chills from reaching -15F across area.

Strong 1050 mb arctic high pressure over central Saskatchewan to
weaken to 1040 mb as it settles into AR and mid MS river valley by
midday Wed. This should bring more sunshine Wed but still a cold
day with highs in the upper teens and lower 20s. Wind chills
overnight Tue night into Wed morning to range from -5 to -13F.

Arctic high pressure settles into the southeast states Thu and Thu
night while a weak upper level low/clipper moves into WI. This
feature should keep its light snows north of central IL, though
may see increasing clouds northern areas later Thu and Thu night.
SW flow around high pressure in southeast states to bring milder
highs in the low to mid 30s on Thu. Warming trend continues Fri
with highs in upper 30s/lower 40s (near 45F from Jacksonville sw)
and upper 40s/lower 50s on Sat and Sunday. Continued a dry
forecast from Wed through Friday night across CWA. Also continued
slight chances of light rain showers Sat and Sat evening, and
could be mixed precipitation if it occurs early Sat morning.

A strong upper level trof digging over the Rockies this weekend
ejects a storm system ne from near OK panhandle at sunset Sat into
central IA or nw IL by sunset Sunday. This will bring a chance of
rain showers overnight Sat night and likely chances of rain
showers on Sunday across area. Chances of showers to diminish
overnight Sunday night as cold front sweeps east of IL. This will
cool temps closer to normal next Monday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1148 AM CST Mon Jan 15 2018

Skies have partially cleared across much of central Illinois late
this morning: however, satellite imagery is showing re-development
of a thin layer of low clouds within the bitterly cold airmass.
Based on satellite and ob trends over the past couple of hours,
have opted to maintain MVFR ceilings through the afternoon. Winds
will remain strong/blustery today...with northwesterly gusts of
20-30kt. The I-74 terminals have consistently shown slightly
reduced visbys despite an end to the light snow, so have included
BLSN at those sites. Winds will gradually decrease tonight, but
will remain in the 10-15kt range late tonight into Tuesday
morning. MVFR clouds and a few flurries will continue as well...as
an upper trough pivots southward into the region.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon CST today for ILZ027>031-
036>038-040>057-061>063-066>068-071>073.

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

&&

$$

UPDATE...Barnes
SHORT TERM...07
LONG TERM...07
AVIATION...Barnes



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