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000
FXUS63 KILX 111156
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
556 AM CST Wed Dec 11 2013

.DISCUSSION...
ISSUED 257 AM CST Wed Dec 11 2013

Clipper system making good progress, with associated cold front
about to move into southeast Iowa. Main area of light snow
associated with the system has been remaining north of I-80 for
the most part, with rather dry air over the northern CWA as
cloud heights hang around 6000 feet or so. Temperatures tanked
fairly quickly across the southeast CWA where a healthy snow cover
remains, and some locally dense freezing fog has formed in areas
close to the Wabash River.

Initial forecast concern will be with low wind chills tonight and
whether an advisory is needed, however the main focus will be on
the storm system Friday afternoon into Saturday.

SHORT TERM...Today through Saturday:

Will maintain some chance PoP`s across the far north early this
morning, but main threat will be for some flurries along and north
of I-74 with this system. Cold front should be through most of the
area by midday, and through the southeast CWA around mid
afternoon. Have maintained non-diurnal temperature trend, and the
northwest CWA will likely see falling temperatures nearly all day,
reaching the single digits before sunset.

Large high pressure will settle southeast into southern Missouri
overnight. Most low temperatures should be in the evening, and
then level off overnight as winds start to turn southwest due to
the high. After coordination with neighboring offices to the
north, will issue a wind chill advisory for the far northern CWA
(mainly Galesburg to Peoria to El Paso northward). Worst of the
wind chills will likely be in the evening, before the wind settle
down a bit, but then worsen again around sunrise as the winds
start to increase.

Upper low currently southwest of San Diego still progged to open
up into a wave as it traverses the 4 Corners region Thursday
night, before emerging into the central Plains on Friday. Have not
made too many changes to precip chances Friday afternoon and
evening, with the entire forecast area likely to be seeing some
precipitation by Friday evening. Have maintained the snow/sleet
mix initially as thermal profiles a narrow wedge of warmer air
around 825 mb, but this should quickly switch to snow in much of
central Illinois as evaporative cooling takes place. The southeast
CWA is a bit more iffy on the switchover, with sleet and
potentially some light freezing rain also possible. The snow
should end from west to east on Saturday, potentially as a
rain/snow mix in the afternoon. Currently looking like this should
be an advisory type system, with a few inches of snow possible.

LONG TERM...Sunday through Tuesday:

Still a few longer term questions on the breakdown of the
persistent cold pattern. Most recent longer range model runs
provide one final glancing blow of Arctic air on Sunday before
trying to warm things up. However, broader upper troughs will
continue to periodically drop southeast in the active northern jet
stream, sending clipper type systems into the Great Lakes. These
largely appear to remain to our north, so have kept PoP`s at
slight chance levels and out of the worded forecasts for now.

Geelhart


&&

.AVIATION...
ISSUED 555 AM CST Wed Dec 11 2013

Predominantly VFR conditions expected across the central Illinois
terminals through the 12Z TAF valid time. However, a few hours of
MVFR cigs are likely later this morning into this afternoon as a
strong cold front sweeps through the area. The lower clouds will
be along and just behind the front. The front will also be
accompanied by gusty northwest winds. The winds will die off
tonight and skies will become clear as high pressure builds into
the area.

Bak
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY from 6 PM this evening to 8 AM CST Thursday
FOR ILZ027>031.

&&

$$