908 
FXUS63 KILX 151710
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1110 AM CST Thu Nov 15 2018

.UPDATE...
Issued at 1059 AM CST Thu Nov 15 2018

Will continue the winter weather advisory today east of the IL
river through the afternoon with additional snow accumulations
near 1 inch or less, especially west of I-55 where deformation
band of light snow continues late this morning. Another area of
light snow showers was over southeast IL. The latest HRRR model
shows these two area of light snow diminishing into early
afternoon and could mix with freezing drizzle in eastern IL during
the afternoon before ending. May be able to end the winter 
weather advisory a few hours early this afternoon especially 
western portions as clouds decrease late this afternoon over
western IL and over central and eastern IL during this evening.

A strong 540 dm 500 mb low was over southern IL late this morning
with band of light snow pivoting around it. A weak 1018 mb surface
low pressure was over west central IN, with another one in east
TN. Stronger low pressure pressure 1010 mb off the southern NC
coast near Wilmington, NC. Models take strong cutoff mid/upper
level low from southern IL into north central KY by early evening.
Meanwhile surface low pressure near the NC coast deepens to 1006
mb by sunset as it tracks northward near the VA/Maryland coast.
Energy of this storm system transferring east toward the mid
Atlantic coast storm system during this afternoon, hence our 
light snow bands will be diminishing which most hi-res models 
continue to show. Nearly steady temps of 27-32F over central IL 
and lower 30s from I-57 east, to only climb into the low to mid 
30s for highs today. Far nw CWA by Galesburg to reach upper 30s 
where sunshine over Iowa returns sooner west of IL river during 
the mid/late afternoon.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 329 AM CST Thu Nov 15 2018

Ongoing winter storm this morning bringing plenty of snow across
central Illinois. Dry air already working into the system with a 
significant dry slot working into the southeastern portions of the
state. Though mostly snow at this point, the system did start 
with some sleet and freezing rain, especially in the east. Dual-
pol radar products showing both mixed precip and a more expansive 
melting layer just over the border into Indiana, where ice has 
been more prevalent through the overnight hours. Deformation band 
setting up over Central IL has made its way NW of I-55, taking 
some of the snow even further to the NW. Considering the weakening
dynamics into the remainder of the afternoon, even given the 
additional one to two inches along I-55 this morning...the Winter 
Weather Advisory looks to be in good shape. Further to the NW 
should be limited and potentially short-lived as the main low 
begins more of an eastward track, shifting that weakening axis of 
higher snowfall rates back to I-55. HRRR and GFS to a certain 
extent a little aggressive with the snowfall between I-55 and the 
Illinois River Valley later today, especially as the snow has yet 
to make it that far...that area should fall short of advisory 
criteria...but will continue watching closely. 

Expect a loss of ice crystals this afternoon and a potential for
drizzle/freezing drizzle, particularly east of I-55 as the dry air
continues to work into the system as it weakens/moves out to the
east. Tonight will be clearing and quite cold, dropping into the
20s, although areas with significant snow pack may see that
forecast drop a bit further with the next run. 

.LONG TERM...(Friday through Wednesday)
ISSUED AT 329 AM CST Thu Nov 15 2018

Temperatures through Friday and Saturday expected to be a bit 
above normal, again dependent on snowfall from this system. A more
zonal pattern takes shape aloft into the weekend, but not before a
Clipper like wave dips into the Northern Plains/Midwest for the
weekend. The elogated wave stretches across the region, bringing 
some low chance pops for snow through Central IL for much of the 
weekend. Some models are changing up the precip type, so for now,
will leave the rain/snow mix. In the midst of a pattern change,
expect the details on this system to be in flux through the next
couple runs.  Temperatures warm slightly as southerly flow kicks 
in ahead of the next system through the first half of the work 
week, and so far, dry.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1111 PM CST Wed Nov 14 2018

Snow/sleet mixture has reached KCMI as of 05Z and will be near
KSPI/KDEC shortly. A quick changeover to snow is expected, with
much of the activity concentrated through 12Z. Expect ceilings 
and visibilities to descend to IFR levels as the snow becomes 
more widespread. While KPIA will miss out on much of this snow
before 12Z, short-range models continue to suggest a narrow
north/south band near the Illinois River during the morning and
midday hours. Toward KDEC/KCMI, the precipitation will diminish
by mid morning, perhaps ending as a bit of rain or freezing rain
before the system exits mid afternoon. Skies are expected to clear
during the 21-24Z period from west to east. 

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM CST this evening for ILZ031-
037-038-041>057-061>063-066>068-071>073.

&&

$$

UPDATE...07
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Geelhart