Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 141800
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
100 PM CDT Mon Apr 14 2014

.DISCUSSION...
ISSUED 1045 AM CDT Mon Apr 14 2014

Will update the forecast to bring in a chance of light snow to
areas nw of the IL river a few hours sooner during midday while
having patchy light rain showers/drizzle mixing with light snow
over rest of central IL during the afternoon and over eastern IL
this evening. Snowfall amounts on grassy surfaces still appear
minor, near a half inch or less north of I-70 by midnight with
little or no snow in southeast IL from I-70 south. The cold front
is about to pass se across the Wabash river near Lawrenceville
which currently is 63F. Temps have already fallen into the upper
30s and lower 40s over central IL with brisk nnw winds 15 to 25
mph and gusty. Will continue falling temps over se IL into the
low to mid 40s during this afternoon with temps hovering in the
upper 30s over the IL river valley.

07

&&

.AVIATION...
ISSUED 1259 PM CDT Mon Apr 14 2014

Expect scattered light rain showers to redevelop across the
central IL airports this afternoon. The light rain will mix with
and change to light snow during the afternoon and early evening with
MVFR vsbys possible at times. MVFR ceilings will also continue
across the central IL airports through this evening and then
scatter out from west to east between 05Z-09Z starting at western
taf sites of PIA and SPI and last at eastern taf site of CMI.
Blustery NNW winds 14-18 kts with gusts 20-28 kts this afternoon
will diminish to 10-15 kts after sunset and be NW 7-13 kts later
tonight and Tue morning. Strong cold front over central IN into
far nw KY has passed se of IL by midday. Strong upper level trof
and embedded northern stream short wave over the upper Midwest
will settle into IL this evening, then shift east of IL by dawn
Tue as surface high pressure ridge shifts into the eastern plains
Tue morning. Nearby upper level trof could still produce at least
scattered cumulus clouds around 3k ft Tue morning especially in
eastern IL and broken cu/stratocu ceilings by midday Tue may be
near or just east of CMI.

07

&&

.PREV DISCUSSION...
ISSUED 300 AM CDT Mon Apr 14 2014

SHORT TERM...Today through Wednesday

07z/2am surface analysis shows cold front just west of the
Illinois River, with main area of rain well east of the boundary
across Kentucky and Indiana. Front will progress eastward through
the region early this morning, exiting the E/SE KILX CWA between
12z and 15z. With deepest fetch of moisture displaced well to
the east and deformation zone precip across Iowa shifting
northeastward into Wisconsin, a distinct lull in precip chances
will occur across central Illinois this morning. Forecast
soundings show a relatively shallow layer of low-level moisture in
place, resulting in overcast conditions and perhaps a few
scattered showers. Better precip chances will return this
afternoon/evening as a northern stream short-wave currently
pushing through the Dakotas approaches from the northwest. As
synoptic lift increases and soundings moisten, showers will become
more numerous across the area. Enough cold air will arrive aloft
to support a rain/snow mix across the western half of the CWA this
afternoon, although air temps in the upper 30s and warm ground
conditions will prevent any snow accumulation. Once the sun goes
down and temps begin to drop, the precip will change to
predominantly snow this evening before shifting eastward and
coming to an end by midnight. A minor accumulation of a couple
tenths of an inch will be possible, especially across the NE CWA
around Champaign and Danville. Once precip ends, skies will clear
from west to east overnight. Numeric guidance is showing very cold
low temps dipping into the lower to middle 20s: however, think
initial cloud cover and continued brisk northwesterly winds will
keep readings from dropping quite that low. Instead, will forecast
lows mainly in the upper 20s and lower 30s.

High pressure will build into the Midwest on Tuesday, resulting in
diminishing winds and a return to sunny skies. Despite sunshine,
afternoon high temperatures will remain well below normal for this
time of year in the 40s. Once high pushes eastward, a strong
southerly return flow will develop on Wednesday. Forecast
soundings and numeric guidance suggest wind gusts potentially
reaching 35 mph by afternoon. Given ample sunshine and strong
southerly flow, high temperatures will rebound well into the 50s.

LONG TERM...Thursday through Sunday

The extended forecast will be characterized by a warmer/wetter
pattern. Once deep upper trough initially in place over the Great
Lakes/Midwest shifts eastward, a progressive zonal flow will take
hold across the CONUS for the end of this week into early next
week. The end result will be a return to near normal temperatures
in the 60s with periodic chances for rain. After a warm/dry day on
Thursday, the first in a series of systems will track into the
region Thursday night into Friday. Models are in fairly good
agreement with the timing and track of this feature, with the
ECMWF/GEM remaining just slightly slower than the GFS. Will
continue with chance PoPs across the western half of the CWA
Thursday night, then across the board on Friday. Another warm/dry
day will be on tap in the wake of this system on Saturday. After
that, model discrepancies still exist concerning potential
disturbance on Easter. All models show a 500mb wave passing
through the Midwest on Sunday. The difference is that the GFS
remains dry with this feature, while both the ECMWF and GEM are
developing showers. While moisture will be somewhat lacking due
to limited return flow from the Gulf of Mexico, think strength of
upper wave and good agreement between the ECMWF/GEM warrants a
mention of showers for Easter Sunday.

Barnes

&&

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

&&

$$







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