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000
FXUS63 KILX 090757
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
157 AM CST Sun Mar 9 2014

.DISCUSSION...
ISSUED 156 AM CST Sun Mar 9 2014

Lingering stratocumulus continues to erode early this morning from
the north, as a high pressure axis sinks southward across the
state. Coldest air has lagged behind a bit, but temperatures have
fallen into the teens and lower 20s underneath the axis. Larger
shield of cirrus dropping southeast from the northern Plains,
associated with a warm front. Upper air pattern showing
significant digging across New Mexico and west Texas associated
with the southern jet stream, with the northern stream basically
affecting the Canadian border states. One trough in this stream
has pushed through most of the CWA, trying to tie into the digging
across New Mexico.


SHORT TERM...Today through Tuesday:

Main forecast issue during this period is with the temperatures,
as the upper flow becomes more zonal for a couple days. Have not
made much change to the temperatures, with 60s widespread by
Monday. Weak frontal boundary swinging through the Great Lakes
should drop across the CWA Monday night, before becoming
stationary for a time. Depending on how far south this manages to
penetrate, temperatures across the north could be significantly
cooler on Tuesday due to the tight thermal gradient across central
Illinois but for now will keep 50s for highs across the north and
60s south.


LONG TERM...Tuesday Night through Saturday:

Midweek storm system remains the primary focus for this part of
the forecast. Surface low pressure will intensify across Kansas on
Tuesday, on the tail end of the previously mentioned stationary
front, as a progressive upper trough drops southeast in the
northern stream. Models still trying to phase the two streams back
together, with an upper pattern similar to what`s happening now,
although the northern wave will dominate for us. There is a
general model consensus in taking the surface low across the lower
Ohio Valley Tuesday night, with the GFS and ECMWF in the stronger
solutions and the NAM/GEM on the weaker side. Only the ECMWF shows
a significant deformation zone of precip lingering into Wednesday
morning, with the other models pretty much focusing on the
nighttime hours. Have lingered some light precip east of I-55 in
the morning and east of I-57 through the day. While precip in the
southeast should mainly be rain during the night, the passage of
the deepening upper trough on Wednesday will quickly bring cold
air down, with 850 mb temps falling to around -10C by midday, so a
transition to snow is definitely plausible. Will need to watch
temps closely, as latest ECMWF MOS guidance came in with highs
only in the lower 30s in the southeast, with falling temperatures.
For now will go rain/snow in most areas during the day.

Beyond that, a quick shot of cold air Wednesday night will quickly
give way to another milder period, with highs back in the 50s on
Friday and Saturday. GFS/ECMWF both in general agreement with dry
weather, as a strengthening surface low passes just north of the
Great Lakes on Friday.

Geelhart

&&

.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

&&

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

$$