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000
FXUS63 KILX 111148
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
648 AM CDT Tue Mar 11 2014

.DISCUSSION...
ISSUED 803 AM CDT Tue Mar 11 2014

Mild weather has persisted into early morning in many areas, with
above freezing conditions reported over the entire forecast area,
and some temperatures still near 50 degrees over the southeast.
Surface low pressure is organizing over western Kansas, as a
digging upper trough advances eastward across Idaho and Utah. A
warm front arches northeast from the low to around the I-80
corridor in Iowa, then becomes a cold front as it extends
northeast across Lake Michigan.

Main forecast focus is with the snow accumulations and winter
weather headlines for tonight and early Wednesday. Hopefully this
will be the last time we have to worry about this for the season,
but no guarantees given how the winter has gone so far.

SHORT TERM...Today through Thursday:

Initial concern before the snow is with temperatures today. Will
be a rather sharp temperature gradient as the boundary settles
into central Illinois before becoming stationary this afternoon.
Evening model runs converging on the front reaching the I-72
corridor by late afternoon, and areas to the south will likely
enjoy temperatures reaching the lower 70s.

Strengthening surface low will ride east along the front today.
Most of the models are tracking the low across far southern
Illinois, although the NAM is a bit further north, roughly along
the I-70 corridor. Impressive 700-500 mb omega and steepening
lapse rates overspread the area this evening, adding a convective
concern to the precipitation. Indeed, the latest Day1 SPC outlook
does give 5% chances of severe hail/wind across the southern CWA.
Looking at the soundings, transition from rain to snow should take
place late in the evening across the far north, along the I-55
corridor shortly after midnight, and across the southeast CWA late
in the night. Going with a widespread 2-4 inches from I-72
northward, with some 5-6 inch totals possible around Bloomington,
although convection could definitely throw a wrench into these
projections. Will go ahead and issue a winter weather advisory
along I-72 to Danville, then northward, beginning late this
evening and running through midday Wednesday. In addition, winds
will crank up behind the low and gust from 30-40 mph overnight
into early Wednesday. The wet snow may limit the extent of the
blowing snow potential, but will add some patchy blowing snow
where the heavier snow accumulations are expected.

Quick shot of very cold air is on tap Wednesday night, with teens
for lows, but temperatures rebound back into the 40s on Thursday.

LONG TERM...Friday through Monday:

Gradual cooling trend to take place again during this period, as
upper ridge establishes itself along the West Coast, with a
resulting trough pattern over the Great Lakes north to Hudson Bay.
Longer range models having a bit of difficulty phasing periodic
shortwaves over the central U.S., but would generally support dry
conditions until about Sunday afternoon. Upper pattern should
start becoming more progressive early next week, as the western
ridge breaks down.

Geelhart


&&

.AVIATION...
ISSUED 641 AM CDT Tue Mar 11 2014
Trend of the forecast remains solid. Light and variable winds and
mid level clouds through most of the day as a front settles into
the region. Not until later this evening will the clouds start
lowering in advance of the approaching system. A bit of
variability with the wind directions depending on location of the
boundary going into the evening hours and remaining gusty in the
overnight as rain spreads across the terminals. Gusty conditions
may be further enhanced by convective potential nearest to SPI DEC
and CMI this evening. Cold air moving in will start to changeover
the rain to snow closer to midnight. For now, the trend is in the
forecast with the LIFR drops for now confined to the northern
terminals after 07Z.

HJS
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY from 10 PM this evening to 1 PM CDT
Wednesday FOR ILZ027>031-036>038-040>051-053.

&&

$$