200 
FXUS63 KILX 100534
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1134 PM CST Sat Feb 9 2019

.UPDATE...
Issued at 915 PM CST Sat Feb 9 2019

Moisture flow into the area appears delayed from previous model
forecasts, based on the latest satellite, surface observations, 
and high resolution forecast soundings. The onset of snow may
delay until after 12z in most of our area, with just the far
southern counties possibly seeing snow flying by 12z. Have
therefore delayed the northward expansion of precip late tonight,
and also adjusted the coverage and progression of PoPs/Weather
tomorrow. We still expect a relatively fast moving band of snow to
lift N-NE through central Illinois tomorrow, producing around 1/2"
to 3/4" of snowfall. Precip type may transition to freezing rain
or freezing drizzle from late morning through the afternoon, as
precip begins to diminish and we lose ice crystals aloft. Icing
from freezing precip is not expected to become a major problem,
but slippery travel is expected due to a combination of light snow
and possible freezing rain/drizzle. 

Low temperatures tonight still look reasonable, with high clouds
increasing late, helping to stabilize the diurnal temp falls. Lows
should remain in the low 20s, or only about 2-3 degrees below
current readings. 

Updated forecast info is already available. 

&&

.SHORT TERM...(This evening through Sunday)
ISSUED AT 337 PM CST Sat Feb 9 2019

The active weather pattern will resume tonight into Sunday as an 
upper level wave rapidly ejects northeastward across central IL. 
Snow will spread rapidly into the area early in the morning. By 
noon, the trough axis will already be past the area, leading to a 
diminishment of lift and end of precipitation from southwest to 
northeast through the afternoon. At the same time, a loss of ice 
crystal formation aloft could lead to freezing drizzle or drizzle 
from the afternoon into evening as the precipitation ends. The 
freezing line looks to be around I-70 to I-72, so areas to the north 
will be more prone to icing, however weak ambient afternoon solar 
radiation should help to minimize any impacts from ice accumulation 
in the afternoon. Lows tonight should be in the low 20s, likely 
during the evening, as near steady or slowly rising temperatures 
continue into the morning with the increasing cloud cover. Highs 
Sunday in the low 30s I-72 northward, ranging to the upper 30s south 
of I-70.

.LONG TERM...(Sunday night through Saturday)
ISSUED AT 337 PM CST Sat Feb 9 2019

A deepening surface low will begin approaching Sunday night, as warm 
advection aloft starts to spread precipitation back north into 
central IL. Enough of a warm layer aloft should develop to produce 
an area of freezing rain from around I-70 to as far north as I-72 
through noon Monday, while temperatures remain above freezing well 
south of I-70 overnight Sunday night. Monday afternoon highs look to 
reach the mid 30s north of I-72, with upper 30s to low 40s along and 
south. The result should be a mix of snow and rain to the north, and 
rain to the south. Warming continues Monday night as the warm front 
surges northward across the area, bringing a change to rain. This 
should be short-lived, however, as the cold front sweeps eastward 
across the area Tuesday bringing a decrease in temperatures, a 
change over to snow again into Tuesday evening, as well as strong 
gusty west winds Tuesday afternoon into Tuesday night. Total 
precipitation amounts through Monday look to range from around 0.75 
inch north of I-72, to around 1.5 inches south of I-72. Snowfall 
amounts look to comprise of a couple periods around an inch or less 
separated by a period of rain.

A gap in precipitation is expected Wednesday, followed by another 
potentially strong storm system Thursday into Friday, again with 
snow changing to rain, and back to snow.&&

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1133 PM CST Sat Feb 9 2019

VFR conditions expected through early morning Sunday, then rapidly
deteriorating conditions in snow will develop after 12Z. Freezing
rain or freezing drizzle will also be possible Sunday afternoon as
we lose ice crystals aloft, especially for KSPI and KDEC. Slippery
travel surfaces will be likely, as snow accumulates on untreated
areas. Any freezing precip could complicate the travel hazards,
adding some light ice accumulation on roads.

Expect IFR cigs and vsbys to develop from 15-19Z, with IFR 
ceilings continuing through the evening. Based on a persistent 
surface pressure gradient through tomorrow, winds should continue 
to be SE 6-10 kts through the period.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Flood Watch from Sunday evening through late Monday night for 
ILZ063-067-068-071>073.

&&

$$

UPDATE...Shimon
SHORT TERM...37
LONG TERM...37
AVIATION...Shimon