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Area forecast discussion
National Weather Service Lincoln Illinois
1106 PM CST Thu Dec 12 2019

issued at 340 PM CST Thu Dec 12 2019

Brisk southwest winds will taper off late this afternoon into
this evening. Relatively mild temperatures are in store for
tonight and Friday with lows around 30 tonight and highs in the
mid 40s Friday, then a cold front will arrive Friday night,
bringing temperatures back below normal by Sunday. The cold front
will also bring a chance for light rain and snow Saturday, as well
as some patchy freezing drizzle as precipitation ends. A stronger
storm system will likely arrive late in the weekend and may bring
accumulating snow to the region Sunday night and Monday.


issued at 741 PM CST Thu Dec 12 2019

Earlier high clouds over eastern Illinois have moved out, leaving
a stratocumulus deck with a rather sharp edge from near Winchester
to the southern tip of Lake Michigan. Temperatures in the clear
area have dipped into the mid-upper 30s, while lower 40s linger
underneath the clouds. The southeast third of the forecast area
should remain fairly clear this evening, before these clouds
finally move in from the west. Earlier forecast generally only
needed some minor adjustments for the cloud and temperature


Short term...(this evening through friday)
issued at 340 PM CST Thu Dec 12 2019

Weak high pressure will bring dry conditions through Friday, as
well as lighter winds, although with plenty of continued cloud
cover. Temperatures will be relatively mild in the warmer air
mass transported into the area with today's southerly winds. Lows
tonight should be around 30 and highs Friday in the mid 40s.


Long term...(friday night through thursday)
issued at 340 PM CST Thu Dec 12 2019

An upper trough will drive a cold front into central Illinois Saturday,
ushering in colder temperatures again, as well as chances for
light rain and snow. Temperatures support a messy mix of rain,
snow, and even brief freezing rain and drizzle as surface
temperatures approach the freezing mark Saturday morning and again
Saturday evening before precipitation fully ends, while a marginal
warm layer accompanies the onset of precipitation and some loss of
ice aloft accompanies the end of precipitation as moisture depth

A stronger storm system will arrive in the region Sunday as warm
advection aloft precedes a low that appears to be headed east-
northeastward up the Ohio River valley Monday. The 12z model cycle
seems to be more consistent than previous cycles with this track,
although some timing and precipitation amount discrepancies
continue. Nevertheless, snow looks to be predominant along the
I-72 corridor into Danville northward, while a mix of rain, snow,
and possibly freezing rain could affect areas closer to I-70
southward. Moderate snow amounts in the neighborhood of a few
inches appear likely across much of central IL, although GFS
ensemble plumes continue to advertise a wide spectrum of
accumulation possibilities.

Dry weather and slightly below normal temperatures are on track
for midweek following monday's system.


Aviation...(for the 06z tafs through 06z Friday night)
issued at 1106 PM CST Thu Dec 12 2019

VFR conditions expected through the period. While some clouds are
occurring as low as 5,000 feet late Thursday evening, any MVFR
type clouds expected to remain well to the northwest. Southerly
winds are slowly diminishing and are not gusty anymore, but should
continue lowering to around 5 knots before sunrise, and remain in
that range through Friday afternoon.


Ilx watches/warnings/advisories...



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