Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 161620

Area Forecast Discussion
National Weather Service Lincoln IL
1120 AM CDT Fri Mar 16 2018

Issued at 1115 AM CDT Fri Mar 16 2018

Approaching precip from the system to the southwest is running
into a couple layers of dry air, per the 12Z ILX sounding. As a
result, the advancing edge is eroding as it moves into the area.
Eventually, the precip will become more widespread tonight, but
for today, the western half of the state is more likely to see any
rain. Temperatures are generally moderate for today with the
clouds increasing throughout the day. No major updates are
anticipated for the forecast...though some tweaks to the pops now
and then may be warranted with the slow progression of the


.SHORT TERM...(Today and tonight)
ISSUED AT 345 AM CDT Fri Mar 16 2018

Early morning surface map shows 1025 mb high pressure along the MN
and Canadian border and ridging into northeast IL. A 990 mb low
pressure was over nw KS with its warm front extending through
southern MO and near the KY/TN border. Radar mosaic shows isolate
band of very light showers or sprinkles along the MS river near
the IL/MO border, while more widespread showers and isolated
thunderstorms were over western MO, sw IA and eastern parts of KS
and Nebraska. Mid/high clouds were moving over sw CWA with fair
skies in ne CWA and increasing ENE winds. Temps at 330 am were in
the upper 20s to around 30F ne CWA, mid 30s to upper 40s sw CWA
and southeast IL with lower 40s along and south of highway 50 and
at Pittsfield and Quincy in far west central IL.

00Z models continue slower trend of bringing in shower chances
from the sw during today as low pressure weakens to 996 mb by
sunset as it moves east across northern KS. Confined low chances
of light rain showers over sw CWA this morning, then gradually
increase pops during mid/late afternoon over CWA, though ne CWA
and east central IL look to stay dry through much of the day, due
to drier easterly flow. Though clouds will be increasing over this
area too. Cooler highs in the low to mid 40s (mildest over
southeast IL), with brisk easterly winds making if feel cooler.

Low pressure continues to weaken as it moves toward the southern
MO/IL border by dawn Saturday. Showers likely tonight, with
isolated thunderstorms south of I-72 this evening where small
MUCAPES present. Meanwhile areas north of I-74 may see rain mix
with or change to light freezing rain during overnight with light
glaze possible especially on elevated surface, bridges and
overpasses. Will issue a special weather statement to address this
concern. Better chances of ice accumulations appear to be ne of
CWA late evening and overnight where winter weather advisories are
posted, as close as LaSalle county, IL. Lows overnight range from
near 32F north of I-74, to 35-40F from I-72 south, mildest
readings along and south of highway 50 in southeast IL.

.LONG TERM...(Saturday through Thursday)
ISSUED AT 345 AM CDT Fri Mar 16 2018

St Patrick`s Day looks cloudy, cool and damp, especially in the
morning hours. Weakening low pressure moves into south central KY
by early Sat afternoon and into ne TN by sunset Sat. Upper level
trof hanging back over central IL Sat morning continues chances of
showers, and diminishing over eastern/se IL during Sat afternoon.
Highs Sat in the mid 40s central IL and upper 40s to around 50F
in southeast IL.

Dry weather returns to area Sat night thru Sunday evening as weak
high pressure settles over area. Mostly sunny skies and milder
low to mid 50s return on Sunday with fairly light winds, so a
pretty nice day expected. Another low pressure emerging over the
central plains Sunday night to track east over the mid MS river
valley Monday night. This to spread a small chance of rain showers
to sw CWA later Sunday night and Monday morning, with increasing
chances of rain showers during Monday afternoon and Monday night
mainly south of I-74. NE/northern CWA will likely stay dry
through the day Monday and possibly into Monday night. Highs in
the low to mid 50s again on Monday. Overnight Monday night into
Tue morning will see light snow chances too. Models continue to
dig a strong upper level trof over the MS river valley including
IL on Tue, keeping cloudy skies along with chances of light
showers and cooler temps, with highs Tue in the low to mid 40s.

Chance of light rain/snow showers continues over eastern IL Tue
night and along IN border on Wed especially in the morning hours.
Highs Wed in the 40s, coolest along the IN border. Strong upper
level ridge building over the great plains Thu to shift east into
IL by Fri, with temperatures warming. Highs Thu in the upper 40s
and lower 50s, and into the 50s on Friday. Next wx system to
spread chances of rain showers into area later Fri and especially
Fri night into next Saturday as low pressure ejects out of the
central Rockies into IL.

The Climate Prediction Center`s 8-14 day outlook for Mar 23-29th
has central IL in a 40% chance of below normal temperatures and
about a 45% chance of above normal precipitation.


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 605 AM CDT Fri Mar 16 2018

VFR conditions are expected to continue through mid evening as
mid level clouds gradually increase. Expect MVFR conditions to
develop from sw to ne late this evening and especially overnight
as rain showers become more likely. 990 mb low pressure over nw KS
will weaken as it tracks to ne KS by sunset, and near St Louis as
a 1007 mb low by sunrise Saturday. Brunt of its rain showers will
stay sw of central IL today, though carried vcsh at SPI this
afternoon. Better chance of rain showers spreading into central IL
during the evening and scattered showers lingering overnight.
Chances of light freezing rain appears to stay north of I-74
overnight and kept mention out of TAFs. ENE winds 10-15 kts and
gusts around 20 kts early this morning, to veer east to ESE by mid
morning with gusts of 18-23 kts possible today. Winds veer back to
the east to ENE during tonight with wind speeds of 9-14 kts.




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