Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 230952

Area Forecast Discussion
National Weather Service Lincoln IL
352 AM CST Thu Nov 23 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 345 AM CST Thu Nov 23 2017

Upper level trof over the Ohio river valley to pull away from IL
during today, as a weak disturbance exits eastern IL during this
morning. Could be some isolated flurries from I-74 ne early this
morning. Otherwise, broken mid level clouds to decrease from west
to east during this morning, with ample sunshine by midday into
early afternoon. A frontal boundary over the upper MS river valley
to wash out as it moves into nw IL by midday. So winds stay SSW
to SW at 5-15 mph during today and increasing amounts of sunshine
to modify temps close to seasonal levels on this Thanksgiving Day,
reaching 45-50F for highs this afternoon.

Nearly zonal upper level flow tonight with weak 1020 mb surface
high pressure ridge over TN/KY/WV to bring fair weather and light
south winds to the area tonight. Lows of 30-35F overnight with
mildest readings from Jacksonville west toward MS river valley.


.LONG TERM...(Friday through Wednesday)
ISSUED AT 345 AM CST Thu Nov 23 2017

The 00Z medium and extended range forecast models generally continue
a dry forecast from Friday through Wednesday except for isolated
light rain showers se of I-70 on Tuesday evening with passage of a
cold front. A 980 mb surface low pressure moves east toward
southern James Bay Canada by sunset Friday, then pulls a cold
front se through CWA during Friday night. Moisture and lift
continue to be focused ne of CWA so will keep a dry forecast
Friday night. Breezy ssw winds on Friday ahead of approaching cold
front warm temps into the 55-65F range, warmest from Springfield
sw. Large surface high pressure then settles into the central
plains on Saturday and over the mid MS river valley on Sunday.
Cooler highs Saturday of 50-55F and mid 40s to lower 50s on
Sunday. Models have been trending not as cool over the weekend as
upper level trof and associated colder airmass is focused more ne
of area.

Upper level ridge building over the Rockies on Sunday, shifts
eastward into the MS river valley on Monday, and into the
Southeast States on Tuesday, as surface high pressure slips off
the mid Atlantic coast. Temperatures to modify again during
Mon/Tue, with highs Mon and Tue in the mid 50s to around 60F. The
GFS and ECMWF models show some differences with handling next
weather system during middle of next week. GFS is quicker than
ECMWF with cold front moving se over area on Tue while ECMWF is
moving cold front thru during Tue night into Wed morning. GEM and
GFS models have a band of qpf over se IL late Tue while ECMWF
model is dry until Wed night with short wave trof moving into the
mid MS river valley, and east of IL over Ohio river valley next
Thu. Due to differences between models and from previous runs,
stayed close to consensus for pops during middle of next week.
Have slight chance of showers in southeast IL Tue evening and then
20-30% pops of showers Wed night, and mixing in with light snow
by overnight Wednesday night especially north of I-70. Highs
Wed/Thu are in the mid to upper 40s, with southeast IL near 50F.


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1045 PM CST Wed Nov 22 2017

VFR conditions will continue through this forecast period. A
band of mid level clouds, in the range of 8-12k ft AGL, were
drifting southeast across the area this evening and that should
continue into the overnight hours. The clouds will decrease from
northwest to southeast Thursday morning with a light southerly
flow tonight (less than 10 kts) increasing from a south to
southwest direction on Thursday at 10 to 15 kts.





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