Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 222021

Area Forecast Discussion
National Weather Service Lincoln IL
321 PM CDT Sun Oct 22 2017

.SHORT TERM...(This evening through Monday)
ISSUED AT 315 PM CDT Sun Oct 22 2017

A strong cold front was moving east toward I-57 at 20Z/3 pm and
will sweep east of the IL/IN border around 00Z/7 pm. Breezy south
winds ahead of the cold front will switch gusty nw behind the
front ushering in much colder air. Temperatures were near 80F
along the Wabash river at Robinson and Lawrenceville where some
peaks of sunshine. Temps fell into the low to mid 50s behind the
cold front along and west of I-55. An area of light to moderate
rain showers were along and west of the cold front and lifting

A 569 dm 500 mb low pressure had recently formed along the
OK/AR/MO border will deep to 564 dm as it moves toward the
southern MO/IL border by 12Z/7 am Monday and to sw IN by 18Z/1 pm
Monday. The upper level low will then open up as it ejects ne into
Ohio by sunset Monday and into the eastern Great Lakes during
Monday night. This feature will likely keep showers around through
Monday morning especially east of the IL river, then becoming
more widely scattered in eastern IL Monday afternoon. Lows tonight
range from mid 40s over the IL river valley, to the low to mid
50s in eastern IL. Highs Monday in the low to mid 60s with coolest
readings in eastern IL where more clouds and showers linger


.LONG TERM...(Monday night through Sunday)
ISSUED AT 315 PM CDT Sun Oct 22 2017

12Z forecast models continue to dig strong upper level trof
southward into IL during Monday night and Tue and more chances of
showers spread sse across area during that time along with
reinforcing colder air. Chances of light rain showers lingers over
ne CWA Tue evening. Lows Monday night in the low to mid 40s.
Highs Tue in the upper 40s from Peoria and Bloomington north and
lower 50s south. Colder lows mostly in the mid 30s Tue night with
some upper 30s southeast of I-70. If wnw winds diminish enough
overnight Tue night, could see some patchy frost formation north
of I-70. Highs Wed in the low to mid 50s, with some upper 50s from
Jacksonville sw as strong upper level trof shifts east of IL into
the eastern Ohio river valley.

Weak upper level ridging into IL Wed night and Thu to briefly
moderate temperatures on Thu. Cool lows Wed night in the upper
30s to around 40F. Highs Wed in the low to mid 60s, mildest sw
CWA. Models then dig another strong upper level low/trof southward
into the Midwest Thu night and Friday driving another cold front
se through the area. Have chances of light rain showers Fri and
Fri night in mainly eastern IL and could mix with light snow
showers overnight Fri night. Highs Fri range from 50F nw of IL
river, to the lower 60s over the Wabash river valley. Lows Fri
night in the mid 30s central IL and upper 30s southeast IL. Strong
upper level trof over IL Sat and Sat night to keep chances of
light showers over central/eastern CWA and could mix with light
snow showers Sat night. Even colder lows Sat night in the low to
mid 30s and some areas could see their 1st freeze of the season.
Highs Sat and Sunday only in the upper 40s/lower 50s except mid
50s in far southeast IL on Saturday. The Climate Prediction Center
(CPC) 8-14 day outlook for Oct 30 thru Nov 5 has a 40-50% chance
of below normal temperatures and precipitation across central and
southeast IL.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1255 PM CDT Sun Oct 22 2017

A strong cold front was near or just east of I-55, recently
passed through SPI and about to pass through BMI early this
afternoon. This front will pass east through DEC and CMI during
mid afternoon from 19-21Z. Mainly light rain showers and some fog
to drive vsbys down to 1.5-3 miles at times with IFR to MVFR
ceilings this afternoon especially behind the cold front. Latest
models continue to show light rain spreading ne across much of
central IL especially from IL river east during much of tonight
and diminishing in east central IL toward midday Monday. lower
ceilings to lift to VFR during overnight into Monday morning
starting at PIA 1st and getting to CMI last. Strong south winds
ahead of cold front with gusts 25-35 kts at BMI, DEC and
especially CMI to turn NW and still have gusts of 20-25 kts this
afternoon. NW winds to gradually subside to around 10 kts or less
during tonight and continue Monday morning.





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