National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KILX 051750
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1150 AM CST Thu Dec 5 2013

.DISCUSSION...
ISSUED 1059 AM CST Thu Dec 5 2013

Updated the forecast and grids to reflect current trends with the
winter weather event impacting east central and southeast Illinois.

Light freezing rain, sleet and light snow is just moving out of
east central and parts of southeast IL late this morning, with
rain southeast of a Robinson-LWV line. This will change to a
mixture shortly, and continue through the early afternoon. Amounts
have been relatively light as LAPS and NAM forecast soundings
indicate some mid level dry air to contend with.

Some partial clearing in the northern forecast area - north of
Springfield to Bloomington line will be short lived as plenty of
mid and high clouds are upstream. A few flurries may occur in
these areas later this afternoon, but nothing significant is
anticipated.



&&

.AVIATION...
ISSUED 1150 AM CST Thu Dec 5 2013

TAFs written to reflect some lingering MVFR in CMI TAF early in
the afternoon, otherwise VFR conditions this afternoon as the cool
drier boundary layer air moved into TAF sites. Models though do
show 2 waves of pcpn moving up from the southwest US. Much of the
lower cigs and pcpn with be south of TAF sites, however CMI and
DEC may have some MVFR cigs after 12z.

Goetsch
&&

.PREV DISCUSSION...
ISSUED 253 AM CST Thu Dec 5 2013

Approaching winter storm continues to be the primary concern
with this forecast package. Accumulating snow is expected across
the E/SE KILX CWA later today through Friday.

SHORT TERM...Today through Saturday

Strong cold front has pushed east of the Illinois/Indiana border
early this morning, allowing a rapid drop in temperatures across
the area. 08z/2am readings have already slipped into the upper 20s
along/west of the Illinois River, but remain in the upper 40s in
the Wabash River Valley. Temperatures will continue to drop over
the next couple of hours, then will remain nearly steady for the
remainder of the day. Afternoon temps will range from the upper
20s west to around 40 degrees far southeast.

Wave of low pressure will develop along the departing cold front
and track northeastward into the Ohio River Valley later today.
Models have made some minor changes from their previous
forecasts, mainly to bring precip into the SE CWA faster today and
to sharpen up the northwest edge of the precip shield tonight and
Friday. Thermal profiles remain virtually unchanged, with a warm
layer aloft supporting mixed phase precip along and south of a Paris
to Shelbyville line this afternoon/evening. Should see a
rain/sleet mix develop initially, before transitioning to all snow
by mid-evening. Further south, a brief period of freezing rain is
likely along/south of highway 50 early this evening before
sleet/snow mix develops toward midnight. As deeper layer of cold
air arrives, precip will change to all snow overnight. Wintry
precip will mainly be confined to locations along and south of a
Jacksonville to Rantoul line, with areas further northwest only
seeing a few flurries.

A second wave of low pressure will track along the front on
Friday, bringing a renewed round of precip to the E/SE CWA.
Airmass will be cold enough to support all snow, with precip
gradually diminishing/shifting east by afternoon. Total snowfall
accumulations from this afternoon through Friday afternoon will be
heaviest south of I-70, where 4 to 7 inches will be likely. As a
result, will be issuing a Winter Storm Warning for Crawford,
Jasper, Clay, Richland, and Lawrence Counties. Further north, 2 to
4 inches of snow will fall along and south of a Paris to
Shelbyville line, where a Winter Weather Advisory will be in
effect. North of there, totals of around 1 inch are anticipated
along a Danville to Taylorville line.

Once the system departs the region, cold and dry weather will be
on tap for Friday night and Saturday, with overnight lows dropping
into the single digits and highs only reaching the lower to middle 20s.

LONG TERM...Sunday through Wednesday

Short-wave is progged to drop southward out of Canada this
weekend, carving out an upper trough over the western CONUS.
Downstream ridging will allow front that is currently pushing east
and south of Illinois to nudge back northward. While models are
still in disagreement as to how much moisture will return
northward, both the ECMWF and GEM have been suggesting that
boundary and deepest moisture will remain further southeast over
the Tennessee and Ohio River Valleys on Sunday. Meanwhile,
approaching western CONUS trough will have much less moisture
associated with it and should generally lift E/NE toward the Upper
Midwest/Great Lakes. End result will be cloudy skies with a period
of light snow across central Illinois Sunday afternoon and night.
A minor accumulation will be possible, but it is still too early
to tell exactly how much. Once the trough arrives, much colder
conditions will take hold early next week, with highs struggling
to rise through the teens by Tuesday.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING from 6 PM this evening to 6 PM CST Friday
FOR ILZ067-068-071>073.

WINTER WEATHER ADVISORY from 6 PM this evening to 6 PM CST
Friday FOR ILZ056-057-061>063-066.

&&

$$