Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 061705

Area Forecast Discussion
National Weather Service Lincoln IL
1105 AM CST Wed Dec 6 2017

Issued at 1104 AM CST Wed Dec 6 2017

A fast moving shortwave will cause increasing clouds this
afternoon. Plenty of dry air preceding the wave should preclude
much in the way of any precip reaching the ground, but a few
sprinkles or flurries can not be ruled out this afternoon and
evening. Better chances for any precip look to be in our SW
counties, but no impact is expected. The current high temp
forecast looks on track, based on how much we have warmed ahead of
the increasing clouds. We should see temps top out in the mid 30s
north and low 40s south.

Gusty west winds will continue through the afternoon and into
the evening, with a few gusts near 30 mph at times.

Skies should see some clearing later tonight, as winds become
northwest and weaken below 10 mph. Low temps tonight will be much
colder than we have seen in a while, with teens and low 20s. Some
light NW winds will continue through Thursday morning, so wind
chills could dip into the single digits by sunrise Thursday.


.SHORT TERM...(Today and tonight)
ISSUED AT 230 AM CST Wed Dec 6 2017

A surface trough was located near the Illinois/Iowa border early
this morning, and will move across the northern parts of the
forecast area through mid morning. Radar returns showing some weak
returns from about Macomb-Rantoul northward to about I-80. So
far, surface reports haven`t indicated anything, but would not be
surprised to see a few flurries falling. Will continue a mention
of flurries through about mid-morning across the northern CWA,
until this trough passes. A shortwave currently over South Dakota
will zip southeast today, and reach west central Illinois by late
afternoon. Several of the high-resolution models eke out some
light precipitation with this feature, though the period of deeper
moisture is fairly limited. Have added some sprinkles to the
forecast west of Springfield this afternoon, with scattered
evening flurries expanding southeast.

Temperatures today should be a tad cooler than yesterday, with 40s
likely south of I-72. However, the cold air advection will quickly
move in this evening, as a strong upper wave drops southeast into
the upper Mississippi Valley. Thus, lows in the upper teens and
lower 20s are on tap tonight.

.LONG TERM...(Thursday through Tuesday)
ISSUED AT 230 AM CST Wed Dec 6 2017

The temperature forecasts remain the primary issue into the first
half of the weekend, as periodic lobes of Arctic air drop
southeast into the Great Lakes. Any significant relief will hold
off until Sunday, as the large upper trough over the Midwest
shifts eastward. The moderation will be short lived though, as
another potent Arctic air mass plunges southward Monday night and

A couple clipper type systems will be moving through during the
period. The first shortwave is coming into better focus over the
Great Lakes region, with both the ECMWF and GFS models suggesting
some light snow accumulations into portions of central Illinois.
This looks to be more of a midnight Friday night through midday
Saturday time frame. With the front preceding the early week cold
air mass, the Canadian model is furthest southwest with the
precipitation, all the way into northern Missouri, while the GFS
and ECMWF both keep the better precip chances closer to the Great
Lakes. For now, will only mention slight chance PoP`s Monday


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 525 AM CST Wed Dec 6 2017

Weak boundary pushing across the TAF sites early this morning, and
winds should turn to the west-northwest by 15Z. Some gusty winds
to around 20 knots expected into mid afternoon. Next weak system
will quickly move in from the northwest late afternoon and may
produce a few showers near KSPI toward 00Z, but chance is minimal
enough to not include VCSH at this time. Main effect will be
another area of clouds lowering to around 4,000 feet, with
KSPI/KDEC more likely to be impacted at that level with this
feature. However, a more widespread lowering of the ceilings will
move in from the north overnight, with ceilings below 4,000 feet
by the end of the period.




SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Geelhart is the U.S. government's official web portal to all federal, state and local government web resources and services.