000
FXUS63 KILX 091736
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1236 PM CDT Sun Mar 9 2014

.DISCUSSION...
ISSUED 1026 AM CDT Sun Mar 9 2014

Ridge of high pressure centered over the Ohio River Valley is
providing mostly sunny skies and cool conditions across central
Illinois this morning. Winds near the ridge axis along/south of
I-70 remain calm, while a light southwesterly return flow has
developed across the remainder of the area. After frosty early
morning lows in the middle to upper 20s, 15z/10am temperatures
have slowly climbed into the 30s. As ridge sinks further
southward, southwesterly winds will increase to between 10 and 15
mph as the day progresses. This will help transport warmer air
into the region, resulting in near normal highs in the upper 40s
and lower 50s. Current forecast is right on track, so no update is
needed at this time.


Barnes
&&

.AVIATION...
ISSUED 1236 PM CDT Sun Mar 9 2014

Cu-field is beginning to develop along/northeast of I-74 from KBMI
to KCMI late this morning, with both sites occasionally reporting
MVFR ceilings. Based on satellite imagery/advection, do not think
BKN ceilings will be predominant, so will just mention scattered
low clouds at those sites. Elsewhere, only a high/thin overcast
will be observed. Brisk southwesterly winds will continue through
the afternoon, with gusts reaching the 15 to 20kt range. Gusts
will subside toward sunset: however, tightening pressure gradient
will lead to continued sustained winds of 10 to 12kt through the
night. Meanwhile, a strong low-level jet will develop this
evening, with NAM forecast soundings showing 925mb winds of 45 to
50kt. Will therefore include low-level wind shear at all terminals
between 03z and 14z.


Barnes
&&

.PREV 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


&&

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

$$