Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 230930

Area Forecast Discussion
National Weather Service Lincoln IL
330 AM CST Mon Jan 23 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 329 AM CST Mon Jan 23 2017

Main feature through Monday night will be the extensive stratus
deck over the upper Midwest that will continue to advect over
central and southeast Illinois bringing cloudy conditions. Perhaps
some thinning of the cloud layer in the afternoon as surface
temperatures max out in the low to mid 40s, but at this point looks
to remain cloudy. Lows tonight generally around 32 degrees, with
cooling limited by cloud cover and lingering low level moisture.

The cloudy conditions will limit fog development so overnight fog
should generally be thin. However, a frontogenetical zone around 850
mb looks to continue eastward across the state coupled with an upper
level shortwave and will bring isolated light showers through early
morning today. Currently the broken band of showers is just west of

Breezy NW winds 10-20 mph will continue much of the day today due to
the influence of the deep low pressure system over the southeast.
Winds to lighten overnight tonight as the low continues
northeastward and pressure gradients weaken over central IL.


.LONG TERM...(Tuesday through Sunday)
ISSUED AT 329 AM CST Mon Jan 23 2017

00Z forecast models continue to build an upper level ridge into IL
by sunrise Tue and shifting east into the Ohio river valley by Tue
afternoon. This should keep most of the CWA dry during the day Tue.
Just have a slight chance of light rain showers over Knox and Stark
counties Tuesday afternoon, mainly late. An upper level trof near
the West Coast, will shift east into the Rockies by Tue morning and
develop surface low pressure over eastern CO and into nw KS. Surface
low pressure tracks toward the IA/MO/NE border by sunset Tue.
Meanwhile weak surface high pressure ridge over IL at sunrise Tue
shifts east into the Ohio river valley Tue afternoon with increase
SSE winds during day Tue bringing milder highs in the upper 40s,
with lower 50s sw CWA. A mostly cloudy day overall for central IL
Tue with more sunshine possible in southeast IL especially south of

Low pressure to track into central IA by midnight Tue night, into
south central WI by sunrise Wed and then toward northern lower MI
and Lake Huron by sunset Wed. Continued 20-40% chances of light rain
showers over northern CWA especially from I-74 on Tue night and Wed
while southeast IL remains dry. Lows Tue night in the upper 30s
central IL and lower 40s southeast IL, with mid 30s by Galesburg.
Highs Wed range from lower 40s over the IL river valley, to lower
50s near Lawrenceville in far southeast IL. Upper level trof digs
into central IL Wed afternoon and Wed night bringing in cooler air.
This to turn light rain chances to light snow chances from nw to se
during Wed night but little or no snow accumulations. Lingered small
chances of light snow or flurries over ne CWA Thu, mainly in the

A major upper level pattern shift will occur Wednesday night and
Thursday across the Midwest, bringing more seasonable winter weather
to the region. A strong upper level low lifts into southeast Canada,
while upper ridging builds over the west coast. A few northern
stream shortwaves will track southeast out of central Canada, and
dig a broad upper level trough over the eastern United States.
These weak shortwave may produce a few flurries Wed night and Thu,
but no accumulations expected over central IL. Temperatures will
cool closer to normal for late January. Highs Thu in the mid to
upper 30s, with lower 30s by Galesburg. Highs in the low to mid 30s
from Friday through Sunday, then back in the mid to upper 30s next
Monday. Lows Thu night in the mid 20s, with lower 20s by Galesburg.
Lows 20-25F from Fri night thru Sunday night.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1146 PM CST Sun Jan 22 2017

Aviation conditions across the central Illinois terminals will
gradually improve during the 06Z TAF valid time as high pressure
slowly builds into the area. However, there will still be an
extended period of IFR or low-end MVFR conditions to contend with
before improvement really takes hold late Monday. Spotty showers
are possible over the next few hours, but coverage/intensity is
likely to be too low to include in the terminals.





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