Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 181544
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1044 AM CDT Fri Oct 18 2019

.SYNOPSIS...
Issued at 400 AM CDT Fri Oct 18 2019

After a frosty early morning across central and eastern Illinois,
ample sunshine will help warm temperatures into the low to mid 60s
this afternoon. Dry conditions will continue tonight as clouds
increase from the west overnight. Lows tonight will be in the low
to mid 40s. A weak front moving into Illinois on Saturday with
bring more clouds with a chance of showers. Highs Saturday will
range from the lower 60s over the IL river valley, to the lower
70s in southeast IL.

&&

.UPDATE...
Issued at 1044 AM CDT Fri Oct 18 2019

After frosty early morning lows in the lower to middle 30s,
15z/10am temperatures have rebounded into the lower to middle 50s
under mostly sunny skies. Satellite imagery continues to indicate
high/thin clouds streaming across the area, but these will do
little to inhibit warming today as boundary layer winds increase
from the S/SE. Projected afternoon highs in the lower to middle
60s are right on target: therefore, the current forecast requires
no major update this morning.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 400 AM CDT Fri Oct 18 2019

Early morning surface map shows weak 1017 mb high pressure over
western IN and eastern IL and western TN. Nearby high pressure was
bringing light to calm winds over central and eastern IL with
frosty conditions with temps in the low to mid 30s east of the IL
river. Will continue the frost advisory thru 8 am over eastern
half of CWA. Temps were in the upper 30s to near 40F along and
west of the IL river where cirrus clouds were spreading east into
western CWA.

High pressure will drift east over the OH/TN river valley today as
upper level ridge over the MS river valley shifts east as well
over the central Great Lakes and OH/TN river valley by sunset.
This will bring ample sunshine today and increasing SSE winds
warming temperatures closer to normal this afternoon with highs
in the low to mid 60s, coolest ne of I-74.

A frontal boundary will push east into the eastern Plains by dawn
Sat increasing clouds over IL overnight while shower chances stay
west of the MS river thru sunrise Sat. Lows tonight in the low to
mid 40s, with upper 40s over west central IL, and coolest near
the Wabash river.

.LONG TERM...(Saturday through Thursday)
ISSUED AT 400 AM CDT Fri Oct 18 2019

00Z model suite have continued to trend slower with chances of
rain showers spreading eastward into central IL during Saturday.
More clouds and better chances of showers over the IL river valley
keeps cooler highs in the lower 60s Sat while se IL likely stays
dry Sat with milder highs around 70 to lower 70s. Surface low
pressure over the central Gulf of Mexico ejects ne into southern
GA by sunset Sat, keeping its convection se of the Ohio river and
models have been consistent on this. Dry conditions expected Sat
night thru Sunday evening across central/se IL. More sunshine and
se flow brings mild highs in the upper 60s and lower 70s on
Sunday, warmest in southeast IL with Lawrenceville near 75F.

A vigorous storm system off the West Coast to emerge over the
Midwest overnight Sunday night and Monday as strong upper level
low and surface low move ne into the upper MS river valley by
sunset Monday. GFS still a bit faster than the ECMWF and GEM
models with cold front moving east toward the IL river valley at
sunrise Monday and to the IN/IL border by 18Z/1 pm Mon. ECMWF and
GEM models about 3 hours slower with cold front. Chances of
showers and thunderstorms to increase from west to east overnight
Sunday night and highest pops shifting into eastern IL and IN by
Monday afternoon. SPC day3 outlook keep marginal risk of severe
storms over Ozarks of sw MO and marginal risk of excessive
rainfall Sunday night is south of MO. SPC Day4 severe risk outlook
for Mon keeps 15% risk area south of KY. Still could be some
strong thunderstorms Mon with gusty winds along with around 1 inch
or higher rainfall amounts in eastern/se IL. Highs Mon similar to
Saturday with lower 60s nw of the IL river and around 70F in
southeast IL. Increased winds on Monday to breezier levels due to
tight pressure gradient.

Chance of showers diminish from west to east Mon evening with dry
conditions with dry and cooler conditions overnight Mon night and
Tue. Strong cutoff upper level low near or north of Lake Superior
on Tue has wrap around showers mostly passing north of CWA but
could see isolated very light showers far ne CWA Tue morning.
Cooler highs Tue range from mid to upper 50s, except lower 60s se
of I-70. Dry and seasonably cool conditions expected Tue night
thru Thu. A strong/sharp upper level trof digs into the MS river
valley by sunset Friday and to bring next chance of showers Thu
night and Friday along with some reinforcing cooler air next
Friday. CPC 8-14 day outlook for last week of Oct (Oct 25-31) has
55-60% chance of below normal temperatures across IL.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 600 AM CDT Fri Oct 18 2019

VFR conditions are forecast to continue across the central IL
airports through 12Z/7 am Saturday. 1018 mb high pressure over
western parts of lower MI/IN and into the mid MS river valley,
will move east into the eastern Great Lakes and mid Atlantic
States by late tonight, while upper level ridge over the MS river
valley also shifts eastward. This will continue fair weather
across the central IL airports through tonight with some passing
cirrus clouds, broken at times into mid morning over central IL and
again during overnight especially west of I-55. East to SE winds
3-8 kts early this morning will veer SE to SSE and increase to
10-15 kts by late morning with gusts around 20 kts by midday and
into the afternoon. SE winds diminish to 5-10 kts after sunset.


&&

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

$$

UPDATE...Barnes
SYNOPSIS...07
SHORT TERM...07
LONG TERM...07
AVIATION...07


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