Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 071732

Area Forecast Discussion
National Weather Service Lincoln IL
1132 AM CST Wed Dec 7 2016

Issued at 1030 AM CST Wed Dec 7 2016

Cool/dry weather will prevail across central Illinois today,
courtesy of a sprawling ridge of high pressure extending from
western Canada to the Ohio River Valley. Despite the high, quite a
bit of mid/high clouds have kept conditions mostly overcast early
this morning: however, latest visible satellite imagery shows a
considerable thinning of the overcast across the W/NW KILX CWA.
Think a period of sunshine will occur for a couple hours before
additional mid/high clouds stream back into the area this
afternoon. Have updated sky trends accordingly. Temperature
forecast appears to be largely on track, with only minor tweaks
necessary. Afternoon highs will range from the upper 20s far
northwest around Galesburg to the upper 30s south of I-70.


.SHORT TERM...(Today and tonight)
ISSUED AT 345 AM CST Wed Dec 7 2016

High pressure ridge sitting across southern IL will keep the surface
winds across the CWA out of the west to northwest next 24hrs. In the
upper levels, a weak trough will move toward the area today,
reaching the CWA overnight. This feature will bring additional
clouds to the area for today through this evening. Due to lack of
moisture in the air, not expecting any precip over the CWA through
tonight. If any thing does occur, it will be very light flurries.
Most of the central and southeast parts of the CWA will see temps
above freezing, while the northern areas, including Galesburg,
Peoria, and Bloomington will be below freezing. The location of the
high pressure ridge will allow much colder temps to advect into the
area for tonight. So, expecting lows ranging from around 15 in the
northwest to the lower 20s in the southeast.

.LONG TERM...(Thursday through Tuesday)
ISSUED AT 345 AM CST Wed Dec 7 2016

Bitterly cold temperatures on the way through the end of the week.
Next precip system for the weekend starting to show some consistency
in GFS and ECMWF.  For now, however, a snowy weekend...starting
Saturday afternoon/evening and through Sunday night.

Cold Arctic air making its way into the forecast area and by
tomorrow, max daytime temps will be in the 20s.  Overnight lows
dropping each day until widespread teens Thu night/Friday morning.
Winds Friday morning will be up a bit, dropping wind chills to
single digits. The freeze will continue through Friday as well.

Temperatures warm slightly for Saturday with southerly winds ahead
of the next wave.  Some differences still in the models with the GFS
persisting with a deeper sfc low, and more amplified flow at h5. The
ECMWF is far more zonal overall, and lingers the precip considerably
longer into Sunday night.  For now, the weekend looks to be
dominated by some snow...with light accumulations for chances for accumulations look to be Saturday night
if the models maintain their current trends.  Snowy Sunday morning
slowly coming to an end as the evening approaches.  Cold through
days 6 and 7, max temps in the 20s and 30s...but will be seeing
another blast of Arctic air for frigid temps by midweek.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1132 AM CST Wed Dec 7 2016

Overcast from earlier this morning has thinned, with mainly just
high/thin clouds noted at the central Illinois terminals. Based on
latest visible satellite loops and upstream obs, it appears mid
clouds with bases between 9000 and 12000ft will return from the
W/SW this afternoon. HRRR continues to suggest MVFR ceilings will
develop across northern Illinois later this afternoon/evening...then
will spread southward into the eastern KILX CWA tonight.
Meanwhile, the NAM keeps any low ceilings well to the N/NE until
Thursday afternoon when a trough of low pressure drops southward
into the area. Since there is no evidence of widespread low clouds
currently forming across northern Illinois/Wisconsin, have sided
with the NAM and decided to wait until the trough arrives Thursday
afternoon to mention MVFR ceilings. It appears only mid/high
clouds will prevail tonight, with lower clouds sinking southward
toward the I-74 terminals by midday Thursday.




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