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Area forecast discussion
National Weather Service Lincoln Illinois
328 am CST Tue Jan 24 2017

Short term...(today and tonight)
issued at 328 am CST Tue Jan 24 2017

A narrow high pressure ridge between the deep low off the East Coast
and low pressure over the mountain west will provide for light and
variable winds through morning today...then the developing low from
the west will move into the Central Plains causing southeast winds
to increase. Expect southeast winds around 15 mph by afternoon west
of I-55, and by evening throughout central Illinois. These winds
should remain breezy through tonight shifting to SW around daybreak
Tuesday as the low heads into the northwest corner of Illinois dragging a
cold front east across the state. Temperatures today should be up
only a few degrees as extensive morning stratus cloud cover
dissipates followed quickly by increasing mid and high cloud cover
damping out diurnal heating, while only weak warm advection occurs
at low levels. Highs expected in the mid to upper 40s. The better
lift and moisture associated with the approaching low is forecast to
remain north of our area. As a result, chance category pops tonight
will continue to be north of I-74 with a slight chance for light
rain showers reaching southward to around I-72. Lows should be mild
as the cold front remains to the west keeping temperatures around 40
degrees...dipping perhaps into the mid to upper 30s behind the front
for areas north of I-72/west of I-55 Wednesday morning.


Long term...(wednesday through tuesday)
issued at 328 am CST Tue Jan 24 2017

00z forecast models continue to track surface low pressure from
southeast Colorado into eastern central Iowa by sunrise Wed, into Central
Lake Michigan by sunset Wed and into southeast Ontario peninsula by
sunrise Thu as it gradually deepens. Forecast confidence if fairly
high with this weather system. The brunt of the rain showers will
stay NW of the Illinois by Knox and Stark counties Wed morning, then
shifts southeast across the Illinois River valley toward I-55 during Wed
morning, as cold front moves into NW Illinois late Wed afternoon and
upper level trof begins to move into Illinois Wed afternoon. Highs Wed
contrast from lower 40s over the Illinois River valley, to the low to
mid 50s in southeast Illinois along and southeast of I-70.

The highest chances of precipitation will occur Wed night as cold
front tracks southeast across central and southeast Illinois and strong
upper level trof moves over Illinois and into the Ohio River valley. Good
chance of rain showers northern County Warning Area early Wed evening, then
precipitation chances spread into southeast IL, though only slight
chances in southeast Illinois. Colder air arriving behind the cold front
to gradually change light rain chances to light snow chances from NW
to se during Wed night. Little or no snow accumulations expected.
Cooler lows Wed night in the upper 20s from I-55 NW and lower 30s
southeast of I-55.

A broad upper level trof then in place of the Midwest/Great Lakes
and Ohio River valley Thu thru this weekend, bringing seasonable
temps, a fair amount of low clouds, along with periodic chances of
flurries. Best chances of light snow showers will be over northeast
Illinois Thu. Highs Thu range from 32f at Galesburg to 38f at
Lawrenceville. Lows Thu night in the low to mid 20s. Highs Fri near
30f from I-74 north and near 35f far southeast by Lawrenceville.
Highs Sat thru Mon mostly in the low to mid 30s, then in the mid 30s
to lower 40s on Tue. Lows mostly in the low to mid 20s, but coldest
night is Sunday night with upper teens central Illinois and lower 20s from
I-70 south. Extended models show a fairly strong cutoff upper level
low digging southeast into the upper Great Lakes overnight Monday
night into next Tue with better chances of snow north of central
IL, north of I-80.


Aviation...(for the 06z tafs through 06z Tuesday night)
issued at 1144 PM CST Mon Jan 23 2017

Predominantly MVFR conditions are anticipated across the central
Illinois terminals through midday Tuesday. Patchy IFR conditions
are also possible. Winds will turn more southerly Tuesday as a
ridge of high pressure passes east of the area, and a storm system
approaches. This should allow VFR condtions to return for most of
the afternoon and evening hours Tuesday.


Ilx watches/warnings/advisories...


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