Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 162338

Area Forecast Discussion
National Weather Service Lincoln IL
538 PM CST Sat Dec 16 2017

.SHORT TERM...(This evening through Sunday)
ISSUED AT 315 PM CST Sat Dec 16 2017

A sunny and pleasant day across central and southeast IL with
breezy sw winds 10-20 mph and gusts of 20-25 mph giving milder
temps in the low to mid 50s, even upper 50s from Springfield and
Jacksonville sw. 1025 mb high pressure over GA and sprawled across
the southeast states while a cold front extended from central IA
thru nw KS to deepening 1000 mb low pressure over se CO. Low
pressure is forecast to weaken as it ejects into the central
plains by dawn Sunday and eject ne over nw IL by Sunday afternoon.
Tonight should stay dry with mid/high clouds increasing from the
ssw overnight. Lows ranging from around 30F from i-74 ne and mid
30s from Springfield and Effingham sw.

12Z forecast models remain fairly consistent in spreading qpf ne
across CWA during Sunday morning, though likely not getting to
I-74 and ne until between 15-18Z Sunday. Could see a very brief
period of light snow/sleet mix at the onset of the precipitation
over central IL as initially dry low levels give evaporative
cooling. Rain to diminish from sw to ne during mid/late Sunday
afternoon and total rainfall amounts only near a tenth inch or
less. Highs in the low to mid 40s Sunday with ssw winds 5-10 mph,
temperature rise held back by overcast skies and light rain.

.LONG TERM...(Sunday night through Saturday)
ISSUED AT 315 PM CST Sat Dec 16 2017

A split upper level pattern takes shape early in the work week
with central IL staying in a quiet and mild wx pattern. Storm
tracks stay over the northern tier states and over the southeast
states from Monday thru Wed night. Some fog and drizzle looks to
develop later Sunday evening into mid Monday morning especially
north of I-72 with light sw winds and lingering low level
moisture/clouds. Lows Sunday night in the mid to upper 30s. Low
clouds to decrease from the west during Monday afternoon, though
eastern IL may not see much sunshine most of the day. SW winds
keep mild temps around with highs Monday mostly in the lower 50s,
with some upper 40s ne of I-74. More sunshine on Tue to warm temps
a bit more, into the low to mid 50s, with upper 40s by Galesburg.

A weak cold front passes through area late Tue and turning cooler
about 10F cooler for Wed with highs in the low to mid 40s. A
southern stream storm system still appears to pass far enough
south of IL on Wed to keep our area dry, though could see more
cloud cover over southeast IL. Have partly to mostly sunny skies

A strong upper level trof digging over the Rockies Wed night to
eject low pressure into the central plains Thu morning with a
frontal boundary extending from se KS into nw IL. Still have small
chances of light rain showers developing nw of IL river during Thu
afternoon, especially late. Highs Thu mostly in the mid to upper
40s, but range from lower 40s nw by Galesburg to 50F far se IL at
Lawrenceville. Precipitation chances spread se across the CWA
during thu night and as colder air arrives, the rain chances to
turn to snow chances in central IL. Kept it all rain se of I-70
overnight Thu night where lows above freezing. Surface low
pressure ejects ne into the central Great Lakes by midday Friday
with some light snow showers Fri morning over area especially ne
CWA. Colder highs Fri range from lower 30s nw of IL river to lower
40s se of I-70. Highs Sat mostly in the low to mid 30s which is
closer to normal levels. A deepening upper level trof over the
nations midsection next weekend to keep seasonably cold temps
around. A low pressure lifting ne from lower MS river valley into
eastern ohio river valley Fri night could bring more snow showers
to eastern/se IL Fri night. Still some differences with models
with how far north southern stream storm track gets next weekend,
and most keep our area dry yet on Saturday and Sat night.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 538 PM CST Sat Dec 16 2017

Primary aviation concern will be with ceilings late Sunday morning
and especially the afternoon. Through 12Z, no real impacts as high
clouds move in and gradually lower toward 10,000 feet. An area of
light rain will be spreading northeast from Missouri Sunday
morning. Air mass is initially dry, but as the lower levels
moisten from the rain, ceilings will gradually lower into MVFR
range by early afternoon. With an inversion setting up later in
the day, odds of any real improvement are marginal at best.




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