Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 212017

Area Forecast Discussion
National Weather Service Lincoln IL
317 PM CDT Sat Oct 21 2017

.SHORT TERM...(This evening through Sunday)
ISSUED AT 310 PM CDT Sat Oct 21 2017

Isolated showers lingered over eastern IL at mid afternoon due to
a weak short wave that will exit ne of CWA next few hours. Clouds
breaking up especially west of I-57 along with breezy south winds
gusting 20-35 mph was helping warm temperatures back into the mid
to upper 70s. Dewpoints were in the upper 50s and lower 60s, with
some mid 50s near the Wabash river valley.

A strong cold front over far western MN to near the NE/IA border
into eastern KS will push east into nw/west central IL around
12Z/Sun and push into nw IN and se IL by 00Z/7 pm Sunday. Latest
models have continued to trend a bit slower with arrival of
showers and thunderstorms overnight and likely not reaching the
IL/IN border after 12Z/7 am Sunday. SPC day1 outlook for late
evening into overnight has marginal risk of severe storms west of
a Galesburg to Rushville line while slight risk remains west of
IL over parts of IA and central and western MO. Mild lows tonight
in the lower 60s. Have likely to categorical pops on Sunday with
thunderstorms possible in the morning and in eastern IL into
Sunday afternoon. Highs Sunday range from lower 60s by Galesburg
to the low to mid 70s in eastern IL.


.LONG TERM...(Sunday night through Saturday)
ISSUED AT 310 PM CDT Sat Oct 21 2017

12Z forecast models develop a cutoff 567 dm 500 mb low near the
AR/MO border by overnight Sunday night and ejects into western KY
by 18Z Monday and then opens up as it lifts ne into the upper Ohio
river valley by 06Z/Tue. This will likely keep chances of rain
showers around east of the IL river Sunday night and Monday.
Lingering chances of showers in eastern IL Monday night. Highs
Monday of 64-68F. Then strong upper level trof digs down into
central IL later Monday night and Tue ushering in even colder air.
Chances of rain showers spread se across central IL during the day
Tue with lingering chances in ne CWA Tue evening. Highs Tue in the
low to mid 50s with areas from I-74 ne struggling to reach 50F.
Lows Tue night in the mid to upper 30s and could be some patchy
frost late Tue night if nw winds weaken enough. Cool highs Wed in
the low to mid 50s, except upper 50s from Jacksonville sw. Lows
Wed night in the upper 30s, with some lower 40s western/sw CWA.
Patchy frost could be a risk late Wed night near the Wabash river.

Strong upper level trof pulls way from IL from Wed into Thu while
another cold front pushes se toward nw IL by early Thu evening.
Temperatures to moderate into the low to mid 60s on Thu ahead of
this front. Cold front to push se thru central IL during Thu night
and near the Ohio river by early Fri afternoon. Have 20-30%
chances of rain showers se of I-55 overnight Thu night into Fri
morning. Then 20-30% chance of rain showers over most of CWA from
Fri afternoon thru Sat. Highs Fri range from mid 50s from IL river
nw to the lower 60s in southeast IL. Highs only in the low to mid
50s on Sat while lows 35-40F Fri and Sat nights and another risk
of patchy frost.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1259 PM CDT Sat Oct 21 2017

Isolated rain showers possible at DEC and CMI til 20-21Z though
vsbys and ceilings will remain VFR. A weak short wave east of I-55
will exit ne of CMI by 21Z/4 pm and isolated showers to shift
ene of there after 21Z. Scattered clouds of 5-10k ft and broken
cirrus clouds of 20-25k ft to occur this afternoon and evening
though initially be less cloud cover at PIA into mid afternoon.
Breezy south winds 12-18 kts with gusts in the 20s to occur next
24 hours and be strongest during the afternoon and early evening
and again during Sunday morning especially east of IL river/PIA.
A cold front along the Dakotas/MN border into eastern NE and
central KS will approaching the IL river/PIA toward 18Z/1 pm
Sunday. Brunt of showers and isolated thunderstorms to occur
later tonight into Sunday morning, though likely not reaching CMI
until after 12Z/Sunday. MVFR conditions to develop with showers
later tonight into Sunday morning.





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