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FXUS63 KILX 011151

National Weather Service Lincoln IL
551 AM CST TUE DEC 1 2015

.SHORT TERM...(Today)

09z/3am surface analysis shows 1005mb low over southwest Minnesota
with occluded frontal boundary arcing southeastward into
east-central Illinois.  While most of the showers associated with
the system have departed the KILX CWA, low clouds and drizzle
persist across much of the area early this morning.  Latest
satellite imagery continues to show the back edge of the cloud
shield marching steadily northeastward toward the Mississippi
River as a dry slot wraps into the system.  Based on satellite
timing tools, the clearing line should reach a Peoria to
Springfield line by 12z/6am and further east to the Indiana border
by around 17z/11am. Mostly sunny skies are then expected for the
balance of the day across most of the area, with the exception
being locations northwest of the Illinois River where wrap-around
moisture will result in increasing cloudiness by mid to late
afternoon. Thanks to a good deal of sunshine and southwesterly
winds gusting to around 25mph, high temperatures will rise into
the middle to upper 40s...with a few readings around 50 degrees
south of I-70.

.LONG TERM...(Tonight through Monday)

As a deep upper low currently over southwest Minnesota tracks slowly
eastward over the next 24 hours, clouds will spread back into
central Illinois and some light precipitation will be possible
across the north.  Models are in good agreement with the track of
the low and its expected QPF across the area.  Based on both NAM and
GFS output, will carry chance PoPs for light snow along/north of the
I-74 corridor tonight, with a chance for flurries as far south as a
Paris to Taylorville line.  As the low slowly slides by to the
north, light snow/flurries will continue into Wednesday as well.
Snowfall will be quite light with this system, with perhaps a couple
tenths of an inch along/north of I-74 late tonight into Wednesday
morning.  Despite continued light snow or flurries into Wednesday
afternoon, surface temperatures rising into the middle to upper 30s
will prevent further accumulation and may even result in the light
snow mixing with rain.

Once the low departs the region, upper heights will rise
significantly by the end of the week.  Both the GFS and ECMWF
indicate unseasonably high 500mb heights of 582 to 585dm by
Saturday.  These heights along with a southerly low-level flow and
plenty of sunshine will yield high temperatures around 10 degrees
above normal for this time of year in the lower to middle 50s over
the weekend.

After that, model solutions begin to diverge somewhat early next
week.  Previous runs of the GFS/ECMWF had tracked an upper low
across the Midwest on Monday, resulting in rain chances across
central Illinois.  The 00z Dec 1 run of the GFS now features a much
weaker open wave with no precip tracking through the area, while the
ECMWF still shows a stronger closed system but also keeps things
dry.  Given the trend toward a weaker/drier wave, have decided to
drop mentionable PoPs in favor of just a slight chance for showers
Monday/Monday night.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)

VFR conditions will develop abruptly as a slot of dry air wraps
around a storm system over the upper Midwest. At 12Z...clear skies
will already push in to KPIA-KSPI...and this clearing looks to
arrive at KCMI by around 15Z. VFR conditions expected to continue
until 04-09Z Wednesday when cigs likely to decrease to MVFR again
as the upper low with the storm system shifts closer to central
IL. Light snow showers may accompany the upper low as far south as
central Illinois...but timing of any visibility decrease with
these showers remains too uncertain at this time. Winds W-SW 10-15
kts through the period. Gusts 20-25 kts late morning through


.ILX Watches/Warnings/Advisories...



LONG TERM...Barnes
AVIATION...Onton is the U.S. government's official web portal to all federal, state and local government web resources and services.