FXUS63 KILX 222359

Area Forecast Discussion
National Weather Service Lincoln IL
659 PM CDT Sat Sep 22 2018

.SHORT TERM...(This evening through Sunday)
ISSUED AT 315 PM CDT Sat Sep 22 2018

A widespread area of rain showers along and southeast of Robinson
to Flora line at mid afternoon is starting to diminish a bit past
few hours, but will continue to affect far southeast IL thru much
of tonight. Shield of mid/high clouds west along and se of a
Rantoul to Taylorville line and has been slowly pressing se. The
rain showers are due to overrunning along a frontal boundary
extending from south central TN into northern LA to weak 1011 mb
low pressure in northeast TX. Meanwhile 1026 mb high pressure over
the central Great Lakes was bringing in drier and cooler air into
central IL today on ENE winds of 5-15 mph. Some light rain
showers should mainly be southeast of Lawrence county on Sunday
with skies becoming partly sunny in southeast IL. Lows overnight
in the mid to upper 40s in central IL and 50-55F in southeast IL,
mildest along and south of highway 50 where clouds continue. Temps
warm closer to normal on Sunday with highs in the mid to upper

.LONG TERM...(Sunday night through Saturday)
ISSUED AT 315 PM CDT Sat Sep 22 2018

The 12Z forecast models push moisture nw into southeast IL by
overnight Sunday night with more overrunning along frontal
boundary to out south. Have just slight chance of rain showers in
far southeast IL Sunday evening, then better push of moisture nw
overnight Sunday night with isolated showers up to I-72 and good
chance of showers in southeast IL. Lows Sunday night in the mid
50s northern CWA and lower 60s in southeast IL.

Chance of rain showers mainly southeast of the IL river on Monday
with isolated thunderstorms se of I-55 Monday afternoon. Models
are trending slower with a cold front moving into the upper
Midwest Monday afternoon and Monday night and to keeps its
convection chances nw of the IL river valley. Have just a slight
chance of convection nw CWA Monday night. SPC Day3 outlook has
marginal risk of severe storms nw of IL Monday night. Highs Monday
similar to Sunday in the mid to upper 70s. Milder lows Monday
night in the lower 60s northern CWA and upper 60s in southeast IL.

The cold front to push se toward the IL river valley late Tue
afternoon and thru rest of CWA during Tue night. Have 50-60%
chance of showers and thunderstorms Tue and Tue evening, then
diminishing chances of showers from nw to se overnight Tue night
behind cold front. SPC Day4 outlook for Tue has 15% risk of severe
storms in far southeast IL for Tue afternoon/evening along with
risk of heavy rains southeast of I-70. Highs Tue in the upper 70s
and lower 80s.

Dry, cooler and less humid air arrives for Wed and Thu across CWA
as high pressure settles toward IL by Wed night. Highs Wed in the
upper 60s and lower 70s, coolest nw of I-55. Lows Wed night in
the upper 40s and lower 50s, with mid 40s by Galesburg. Highs Thu
mostly in the lower 70s as clouds increase from the nw during Thu
afternoon. An upper level trof digging into the Midwest Thu/Thu
night to keep best chances of showers north of central IL, though
forecast builder carried isolated light rain showers over IL
river valley Thu evening. Ecmwf model keeps rain showers south of
Ohio river and north of IL on Thu and Thu night, and models have
been trending drier. 1025 mb high pressure settling into IA/IL on
Friday to bring a fairly nice day with highs in the lower 70s, and
some upper 60s north of I-74. A disturbance tracking eastward over
IA, northern MO and into central/northern IL during Friday night
into Sat morning could bring chance of showers and isolated
thunderstorms to areas north of I-70. Highs Sat in the mid to
upper 70s with coolest readings north of I-74. Models have trended
warmer next weekend as upper level ridge builds further north
across the southern states and upper level trof/low near the
Pacific Coast next Sunday. Southeast IL looks drier and warm next
weekend with better chances of showers and possible thunderstorms
over northern/nw IL including northern CWA.


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 659 PM CDT Sat Sep 22 2018

VFR conditions are forecast to continue across the central IL
terminal sites through 7 pm tomorrow. High pressure at the
surface and aloft will remain established across central IL,
providing minimal cloud cover and light E-NE winds. Sustained wind
speeds should remain less than 10 kt.

The GFS and NAMnest are hinting at some MVFR or IFR fog late
tonight, but the NAM, HRRR, and RAP have no fog at all. Therefore,
we are siding toward no fog of consequence with this TAF issuance.




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