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000
FXUS63 KILX 070821
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
221 AM CST Sat Dec 7 2013

.DISCUSSION...
ISSUED 220 AM CST Sat Dec 7 2013

Just some lingering altocumulus across the far southeast CWA early
this morning, otherwise clear skies in place as large 1043 mb high
over southeast South Dakota oozes eastward. Pressure gradient has
stayed up enough to keep winds around 10 mph in many areas, with
wind chills a few degrees either side of zero early this morning
despite most temperatures still 10-15. Core of the brutal cold
still off to the northwest, with temps as low as the -20s in parts
of the eastern Dakotas and western Minnesota.

Aside from the extended cold snap, the main forecast concern
involves precipitation types for Sunday.


SHORT TERM...Today through Monday:

The high will slowly weaken as it moves east into the Great Lakes
later tonight. Temperatures will likely struggle to reach 20
degrees today, especially over the southeast with the fresh deep
snow cover.

Shortwave currently digging over northern California will begin
swinging eastward later today, then lift northeast into the upper
Mississippi Valley Sunday evening. Weak warm air advection will
result in early evening lows, with steady or rising temperatures
overnight. May see a bit of snow spreading in from the south very
late tonight as isentropic lift increases, but main precipitation
event still looks to be Sunday into early Sunday evening. Forecast
soundings are largely indicating snow, with perhaps some sleet or
freezing rain in the far southeast. Drying from the top down would
suggest a transition to some freezing drizzle or snow grains
before ending. A general half to 1 inch of snow appears likely
over the CWA, highest across the northwest which will be closest
to the track of the upper wave. System should rapidly pull
northeast Sunday night/Monday as another large high builds
eastward. Fast moving disturbance potentially may produce a bit of
snow Monday night, but have limited to slight chances for now.


LONG TERM...Tuesday through Friday:

Longer range guidance showing another push of Arctic air southward
around mid week into the Northern Plains, pushing east across the
Great Lakes. This will keep highs well below freezing through
Thursday. Some indications of a pattern change later in the week,
as split upper flow starts to converge over the mid-Mississippi
Valley. This could actually push our temperatures above freezing
by Friday.

Geelhart

&&

.AVIATION...
ISSUED 1131 PM CST Fri Dec 6 2013

The dry cold air has dissipated most of the mid-cloud deck across
all but the far southeast areas. All TAF sites are mostly clear
and will remain that way for much of the next 24 hours. High
pressure centered in eastern SD will continue to slowly build to
the east through the weekend.

Winds will remain NNW through mid-afternoon tomorrow, then shift
to the NE as the ridge axis passes across IL.

Shimon

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$