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000
FXUS63 KILX 090549
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1149 PM CST Sat Mar 8 2014

.DISCUSSION...
ISSUED 857 PM CST Sat Mar 8 2014

Expect skies to begin to clear from the northwest shortly across
central and southeast Illinois as drier air associated with a
ridge of high pressure pushes into the area. However, the clearing
should allow patchy fog to develop due to the added moisture from
the spotty light precipitation earlier today and recent snow melt.
The fog threat will be greatest across the northern portion of the
forecast area where skies will clear the soonest, more significant
precipitation occurred today, and snow has still been around to
melt.

Going forecast had the expected scenario well covered. Tweaked the
grids for the latest hourly trends, especially to delay the
clearing and the associated delay in temperature/dew point fall.


Bak
&&

.AVIATION...
ISSUED 1149 PM CST Sat Mar 8 2014

Skies across the central Illinois terminals are slowly but surely
clearing as a ridge of high pressure builds into the area.  Cigs
should scatter out in the next few hours where they have not
already done so. Patchy MVFR vsbys have developed across the area
and this trend is expected to continue through the night as the
clearing increases. Winds will quickly swing around to the
southwest on Sunday on the back side of the approaching surface
ridge, becoming gusty at time from midday into early evening. As
the gusts subside Sunday evening, LLWS may develop. However, the
setup appears marginal and have not included a mention at this
time.

Bak
&&

.PREV DISCUSSION...
ISSUED 200 PM CST Sat Mar 8 2014

SHORT TERM...Tonight through Tuesday

Main focus this forecast period will be with the above normal
temperatures through Tuesday.

The weak weather system that produced the light rain and snow over
parts of the forecast area this morning into the afternoon hours
will continue to slowly shift away from central Illinois this evening.
Any lingering threat for light rain early this evening over the far
southeast will be gone by mid to late evening as high pressure edges
in from the west overnight. Forecast soundings off the GFS suggest
a general clearing trend from northwest to southeast this evening
as the large fair weather system approaches our area. However, with
the residual moisture left from the light precip that occurred today
we may see some fog form overnight into Sunday morning. With temps
forecast well below freezing, we will have to watch out for some
slick bridge decks and overpasses Sunday morning.

Any lingering fog should lift by mid morning as a drier west to
southwest flow overtakes the area. A fast moving shortwave tracking
well to our north tomorrow afternoon should help increase winds
at the surface by afternoon, which in turn, will push temperatures
well into the 40s north and into the lower 50s southwest. A stronger
shortwave will then track across the northern Great Lakes late
Sunday into Monday dragging a frontal boundary southeast into the
Northern Plains with a prefrontal trof situated from southeast
Minnesota southwest thru central Iowa. Just ahead of this trof, gusty
southwest winds Monday afternoon will mix down some fairly warm
temperatures with highs expected to top out in the upper 50s north
to possibly the upper 60s southwest. Despite the rather warm temps
depicted aloft on forecast soundings, it still may be tough to mix
all the way down from 875 mb, especially across our north and with
as much high cloud cover that is depicted on the soundings.

A cold front will be pushing through the area Monday night into
Tuesday morning without much fanfare as moisture, at least initially,
will be quite limited. It appears the front will stall out along or
just north of the I70 corridor Tuesday so some fairly warm temps
will be seen again Tuesday afternoon south of the boundary, while
further north, temperatures may cool some 5 to 10 degrees from
Monday`s highs. The forecast becomes a bit more complicated for
Tuesday night as the models continue to show some spread with
respect to phasing/no phasing of the 500 mb trof which is forecast
to swing through our area on Wednesday. Latest couple of runs of
the ECMWF have swung over to the more progressive/less phased look,
while the GFS, GEM and UK solutions remain fairly consistent in
the more progressive less phased solutions. Rain should develop
Tuesday evening as the upper system and lift approaches the area
with forecast soundings suggesting a change to some wet snow at
the tail end of the event Wednesday morning, at least across the
north half of the forecast area.

LONG TERM...Wednesday through Saturday

Based on the more progressive solution of the 500 mb trof and the
associated surface low to our southeast on Wednesday, any snow and
rain should quickly push off to our east during the afternoon with
a fairly good shot of 850 mb cold advection depicted over our area
as the system pulls away. That should not last very long as models
indicate the upper flow deamplifies across the central U.S. for a
day or two allowing warmer temps to return for the end of the work
week. Next shortwave late in the week will pass well to our north
keeping any significant threat for precip north as well. Gusty
southwest winds Friday afternoon will push temperatures well into
the 50s again with only slight cooling noted for Saturday as a weak
cold front slips to our south.

Smith


&&

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

$$