Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 141106

Area Forecast Discussion
National Weather Service Lincoln IL
606 AM CDT Wed Mar 14 2018

.SHORT TERM...(Today and tonight)
ISSUED AT 345 AM CDT Wed Mar 14 2018

Strong 519 dm 500 mb low over eastern NY/PA will move off the MA
coast by sunset, while upper level ridging into the high plains
and IL in a nw upper level flow. 1028 mb Canadian high pressure
along the eastern KS/OK border to settle into the southern MS
river valley by sunset while a weak front drops southward into nw
IL by early evening. Cyclonic flow is east of IL today and keeping
stratocumulus clouds east of IL, so a fair amount of sunshine
expected today. Light winds early this morning to veer WSW and
become breezy this afternoon with gusts 20-30 mph north of I-70 and
bring in milder temps. Highs in the mid to upper 40s in eastern
IL and 50-55F over western CWA from Peoria and Springfield west,
with the mid 50s near the MS river valley.

Weak front to push south across central IL during tonight, and
thru southeast IL early Thu morning. This front to pass through
dry with fair skies prevailing tonight as moisture and lift is
quite limited with this feature. Seasonable lows tonight in the
upper 20s and lower 30s as winds gradually diminish during the
night with passage of weak front.

.LONG TERM...(Thursday through Tuesday)
ISSUED AT 345 AM CDT Wed Mar 14 2018

A mostly sunny day expected Thu with lighter winds as weak front
pushes south of CWA by mid Thu morning. Upper level ridge
weakens/flattens some as it shifts into the eastern plains by
sunset Thu. Highs Thu range from upper 40s to near 50F northern
CWA from I-74 north, to the mid 50s in southeast IL from I-70

Low pressure emerging over the central plains by Fri morning to
develop light waa mixed precipitation ahead of a warm front over
sw MO and mid MS river valley. Continued 20-30% chances of light
mixed pcpn sw third overnight Thu night and then chance pops over
central and sw CWA on Friday, with light mixed pcpn possible Fri
morning. Little or no ice/snow accumulations expected then over sw
half of CWA. Lows Thu night range from 25-32F with mildest
readings sw CWA. Cooler highs Friday in the low to mid 40s.

Low pressure system weakens as it moves toward IL overnight Fri
night and likely spreads a band of rain showers changing to light
freezing rain late Fri evening and overnight Fri night. Ice
accumulation north of I-70 should stay less than a tenth inch.
Lows around 30F over northern CWA and 33-34F in southeast IL where
just rain showers occur through Fri night. Isolated light showers
expected Sat mainly in the morning hours, and over southern CWA
Sat afternoon. Could be patchy light mixed pcpn early Sat
morning. Highs Sat in mid to upper 40s, with southeast IL near
50F. Dry conditions expected Sat night through Sunday night as
weak high pressure noses into the great lakes region. Highs Sunday
in the low to mid 50s, and some models showing upper 50s
especially over southern parts of CWA as more sunshine expected on
Sunday and light winds, so a pretty nice day.

Another low pressure system emerges over the central plains Sunday
night and tracks toward central or southeast IL Monday afternoon.
This will likely spread rains showers east over area during Monday
into Monday night. Mixed pcpn possible over northern CWA early
Monday morning if it moves in that fast. Isolated thunderstorms
possible south of I-70 monday afternoon. Low pressure moves into
eastern ohio river valley Tue, with lingering upper level trof
over Ohio river valley and IL to keep more low clouds around along
with a chance of rain/snow showers later monday night into Tue

Stayed fairly close to the blended initialization parameters for
this weekend into early next week. CPC`s 8-14 day outlook for Mar
21-27th has 50-55% chance of below normal temperatures and a
40-45% chance of above normal precipitation.


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 605 AM CDT Wed Mar 14 2018

VFR conditions should continue across the central IL airports
through 12Z/7 am Thu. The main weather concern will be the winds,
including gusty SW winds this afternoon and low level wind shear
(LLWS) this evening.

A 1027 mb high pressure over eastern OK at dawn will weaken to
1023 mb over southern MS river valley by sunset, and be over the
northeastern Gulf of Mexico by sunrise Thu. Meanwhile a weak
front nw of Lake Superior at dawn, will drop southward over
central IL between 03-07Z tonight. Airmass is quite dry over
central IL through tonight and will just see few mid level and
few-scattered high/cirrus clouds. West winds around 5 kts at dawn
will veer WSW to SW and increase to 10-15 kts by midday with gusts
of 22-28 kts during the afternoon, peaking during mid/late
afternoon. LLWS to occur this evening starting by 01Z, with 2k ft
westerly winds of 40-45 kts. LLWS ends from north to south, ending
at PIA around 03Z and SPI by 07Z as weak front passes through.
Winds diminish to around 10 kts after sunset and then 4-8 kts
overnight as winds veer NW to NNW behind the front.





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