Area Forecast Discussion
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FXUS63 KILX 052059
AFDILX

AREA FORECAST DISCUSSION
National Weather Service Lincoln IL
259 PM CST FRI FEB 5 2016

.SHORT TERM...(Tonight)
ISSUED AT 257 PM CST FRI FEB 5 2016

A northern stream short wave trof over the eastern Dakotas into
central Nebraska, will track into nw IL by dawn Saturday. This weak
clipper system will generally keep its light snow/flurries chances
north of CWA during tonight, but will bring in more cloud cover.
Clouds have already been prevalent over central and northern CWA
today with thickening cirrus clouds over some lingering MVFR clouds
over NE half of CWA. Meanwhile southeast IL has mostly sunny skies
at mid afternoon will see clouds increase there as well overight.
1033 mb high pressure over the southern MS river valley and ridging
northward into eastern MO and sw IL will gradually shift into the
southeast states into Sat morning. WNW winds 5-10 mph will become
light and variable this evening and become SSE near 5 mph during
overnight. Lows tonight mostly in the middle 20s.

&&

.LONG TERM...(Saturday through Friday)
ISSUED AT 257 PM CST FRI FEB 5 2016

Mild weather to dominate this weekend before much colder weather
moves into the area early next week. Models very similar with
respect to the strong shortwave forecast to dig southeast into
the upper Great Lakes, and eventually carve out a longwave trof
over the eastern U.S. early next week. Mild Pacific air will
dominate Saturday and Sunday as a strong area of low pressure
tracks east across southern Canada late Saturday through early
Sunday bringing above normal temperatures to the region. Afternoon
temperatures on Saturday will top out in the lower 40s north to
around 50 south, and by Sunday, the mercury should climb in the
mid 40s north to the lower 50s south accompanied by a rather gusty
southwest breeze.

As the cold front progresses southeast into the Midwest later on
Sunday into early Monday, rain chances will start to increase across
the north and over parts of southeast Illinois, with most areas
seeing light snow chances late Sunday night into Monday night as the
much colder air builds south. All models now showing the closed
upper system at 500 mb dropping south into central Illinois on
Monday afternoon with 500 mb temperatures forecast in the -30 to -35
degree C range during that time. The combination of the deep
cyclonic flow and cold advection occurring at all levels should lead
to better coverage of snow showers Monday afternoon with rather
steep low and mid level lapse rates expected. Even so, 30-40 POPs
should cover this type of setup with scattered snow showers
continuing into a good portion of the evening as the upper low
slowly edges away from our area on Tuesday. It still appears any
accumulations will be minor, possibly totalling up to an inch over
the 36 hour period (late Sunday night-early Tuesday) in a few
locations, with the most favorable setup being from Monday afternoon
through early Tuesday when the surface temperatures will finally be
cold enough to support any accumulations.

Coldest temperatures at 850 mb forecast to arrive Monday afternoon
and hold over our area into early Wednesday with the coldest models
close to -18 degrees C as surface temperatures are expected to be
steady or slowly falling, especially during the afternoon on Monday,
accompanied by a gusty northwest wind adding a significant chill to
the air. Scattered flurries will be possible on Tuesday across the
east with the better chances for light snow or flurries shifting
away from our area as the low level flow becomes more anticyclonic
by Wednesday with the center of the cold air mass moving over our
area.

The blustery conditions will hold through Wednesday morning as the
deep upper low only slowly pushes away from the region. Wind chills
are not expected to be as cold as we nitially thought, but cold
enough, with readings ranging from 5 below zero north to 5 above
zero far south Wednesday morning. The deep trof will shift away from
the lower Great Lakes late in the week allowing a moderating trend
to settle in which will bring about a gradual moderating trend on
Thursday and Friday when temperatures will inch back closer to
normal.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 1155 AM CST FRI FEB 5 2016

Broken to overcast MVFR clouds of 1.5-2k ft from PIA and DEC
eastward across east central/ne IL will gradually scatter out
during the afternoon, occurring last at CMI after 21Z/3 pm.
Already have broken cirrus clouds spreading east over central IL
at midday and will see these ceilings gradually lower during
tonight to range from 4-6k ft overnight into Sat morning. MVFR
ceilings should stay nw of IL river/PIA overnight into Saturday
morning along with chances of flurries. These clouds due to a
northern stream short wave trof that tracks ESE across the Midwest
and into IL on Saturday. WNW winds around 5 kts to become light
and variable this evening. Winds will become sw 5-10 kts during
Saturday morning. These fairly light winds are due to 1034 mb
surface high pressure from the lower MS river valley and ridging
northward into MO/KY, that stays close to IL into Sat morning.


&&

.ILX Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...07
LONG TERM...Smith
AVIATION...07


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