Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 160851
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
351 AM CDT Mon Apr 16 2018

.SHORT TERM...(Today and tonight)
ISSUED AT 345 AM CDT Mon Apr 16 2018

Continued the freeze warning for 8 counties in southeast IL along
and south of I-70 through 9 am this morning with temps getting
down to 30-32F. Issued another freeze warning for this same area
from midnight tonight through 9 am Tuesday with lows overnight
around 30F.

09Z/3 am surface map shows 998 mb low pressure over central VA
with surface trof extending into ne lower MI. Canadian high
pressure ridge was nosing southward across the great plains. This
will giving a cold/brisk nw winds 12-22 mph and gusts up to 25 mph
over central and southeast IL early this morning. Temps were in
the upper 20s/lower 30s over CWA, while wind chills were 15-25F.
A strong 537 dm 500 mb low was over northeast IL and another batch
of light snow showers were pivoting se across the IL river valley
and heading toward I-55. Snowfall amounts from Lincoln north
ranged from a trace to 0.2 inch so far. Another area of light snow
and drizzle was se of I-70 and pushing se as well.

00Z models take strong cutoff upper level low into western PA by
sunset with another cutoff low moving over Lake Huron. This will
likely continue isolated to scattered light snow showers this
morning over central and ne CWA, and lingering over ne CWA this
afternoon and early evening. Any additional snow accumulations
should range from a trace to a couple tenths inch, with the higher
amounts over northern/ne CWA. Extensive area of stratocumulus
clouds extends upstream across much of MO, so much of today will
be mostly cloudy to overcast across central and southeast IL with
sw CWA having some decreasing clouds later this afternoon. Highs
only in the upper 30s and lower 40s today, coolest over ne CWA.
Brisk nw winds continue today and make it feel colder. This is
actually a bit cooler than normal lows for mid April.

Another cold night ahead as clouds decrease from sw to ne as nw
winds gradually diminish as high pressure builds closer. Lows in
the mid to upper 20s in central IL and around 30F in southeast IL
where another freeze warning needed overnight until 9 am Tuesday.

&&

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 345 AM CDT Mon Apr 16 2018

Strong upper level low lifts into the St Lawrence valley in
eastern Canada by sunset Tue, while upper level ridge shifts east
into the MS river valley. Ample sunshine Tue to warm highs up into
the lower 50s from I-74 ne and mid to upper 50s sw half of CWA.
This is still a good 10 degrees below normal for mid April. Winds
will trend lighter as the day progresses.

Models have strong surface low pressure emerging over western KS
by sunset Tue and weakening as it lifts toward the IA/IL border by
18Z/Wed and toward sw lower MI by sunset Wed. Continued 20-30%
chance of showers over northern CWA Wed and Wed night, especially
from I-74 north. SPC day3 has general risk of thunderstorms over
northern IL during this time frame, mainly just north of our CWA.
Breezy se winds to start the day to become sw and increase by
afternoon with gusts 25-40 mph by midday Wed and thru Wed
afternoon. Highs Wed range from mid to upper 50s over northern CWA
to 65-70F in southeast IL where more sunshine expected. Cooler
highs of 50-55F on Thu. High pressure settles east into the area
Thu night and Fri keeping it dry and rather cool with highs Fri in
the mid to upper 50s.

00Z models continue to trend slower with large cutoff upper level
low moving into the central/southern Rockies late this week and
into the mid to southern MS river valley on Sunday. Best chances
of showers now appears sw of CWA this weekend and only have slight
chances of showers over mainly southern portions of CWA. Highs
mostly in the upper 50s/lower 60s from Saturday through Monday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1045 PM CDT Sun Apr 15 2018

Little change from the previous forecast with mostly MVFR cigs
expected overnight into at least Monday morning. There may be some
cigs drop occasionally to IFR with any light snow shower activity
that may affect a terminal site. At the same time, surface
observations to our west and northwest indicate cigs at times
rising to low VFR category as the upper low shifts slowly off to
our east and north later tonight. MVFR with occasional low VFR
cigs expected Monday with cigs becoming scattered to occasionally
broken after 00z as low pressure moves away from our area and
high pressure approaches from the west. West to northwest winds
will continue through Monday evening with speeds in the 12 to 17
kt range with a few gusts up to 23 kts at times before winds drop
off significantly after 00z Tuesday.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 9 AM CDT this morning for ILZ062-063-
066>068-071>073.

Freeze Warning from midnight tonight to 9 AM CDT Tuesday for
ILZ062-063-066>068-071>073.

&&

$$

SHORT TERM...07
LONG TERM...07
AVIATION...Smith


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