Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 161107

Area Forecast Discussion
National Weather Service Lincoln IL
607 AM CDT Wed Oct 16 2019

Issued at 400 AM CDT Wed Oct 16 2019

Brisk northwest winds in the wake of a cold front will usher in
much cooler air today over central and southeast Illinois, along
with a fair amount of low clouds occurring today. High pressure
over the central Plains will drift into the mid Mississippi river
valley on Thursday, and bring dry weather through Friday. The next
chance of showers and isolated thunderstorms will arrive overnight
Friday night over the IL river valley, and across the area on
Saturday as a weak front moves in. Below normal temperatures
today through Thursday will gradually modify back above normal
late this week, with mild temperatures expected this weekend.


.SHORT TERM...(Today and tonight)
ISSUED AT 400 AM CDT Wed Oct 16 2019

Early morning surface map shows 999 mb low pressure over central
Lake Huron with its cold front extending southward through central
Ohio and eastern parts of KY/TN. A dry slot covered much of
central and southeast IL during the past few hours, though a
curtain of low stratocumulus clouds was dropping southward across
northern IL into far northern CWA. Aloft a strong 541 dm 500 mb
low was spinning over nw lower MI and embedded in a deep upper
level trof over the Midwest/Eastern US. Breezy WNW winds gusting
to 15-25 mph at times had cooled temps into the low to mid 40s
over central IL and upper 40s to near 50F in southeast IL at 4

Latest models deepen 500 mb upper level low to 536 dm as it tracks
east to just south of Georgian Bay Canada by sunset. Broken to
overcast stratocumulus clouds will continue to spread southward
over central IL this morning, with mostly cloudy skies overall
today with brisk nw winds gusting up to 20-30 mph making it feel
even cooler. Highs today only in the low to mid 50s, with even
some upper 40s possible ne of I-74.

Models are slower with clearing of low clouds tonight, and even
show some mid/high clouds streaming se into the area by early
overnight and diminishing toward sunrise Thu. Lows tonight in the
upper 30s and could be some patchy frost late tonight/early Thu
morning over southeast IL and sw CWA where winds diminish quicker

.LONG TERM...(Thursday through Tuesday)
ISSUED AT 400 AM CDT Wed Oct 16 2019

1026 mb high pressure over the central Plains to drift into the
mid MS river valley by midday Thu and into the eastern parts of
the Great Lakes and Ohio river valley on Friday. Meanwhile an
upper level ridge over the Rockies to move eastward over IL by
dawn Friday. This will continue dry weather thru Friday evening
across the area. Mostly sunny skies and lighter winds Thu with
highs in the upper 50s to near 60F. Another cool night Thu night
with lows in the upper 30s and lower 40s, coolest in eastern IL
closer to retreating high pressure ridge. Patchy frost possible
near the Indiana border overnight Thu night and early Fri morning
where lows could reach the mid 30s. A nice fall day expected on
Friday with partly to mostly sunny skies. South winds 5-15 mph to
warm temps into the mid 60s, with some upper 60s over western CWA.

Low pressure passes between Lake Superior and Hudson Bay Canada
late Fri night and Saturday with a weakening front moving east
into IL on Saturday afternoon. Have 20-30% chance of showers and
an isolated thunderstorm over the IL river valley overnight Fri
night, across the area on Saturday, and east of the IL river Sat
evening. Though most of the time it should be dry with more clouds.
ECMWF is painting a wetter solution on Saturday though sided with
less qpf of the GFS and GEM models as gulf moisture initially is
cutoff off late this week. Highs Sat in the mid to upper 60s in
central IL and lower 70s se of I-70. Sunday appears to be the
mildest day with highs mostly in the lower 70s, with Lawrenceville
near 75F and some upper 60s northern CWA.

A stronger storm system moves into the central/northern plains on
Sunday and into the Midwest during Sunday night and Monday as
strong low pressure ejects ne of MN by sunset Monday. This will
bring a cold front east thru IL during Monday. Good chance of
showers and some thunderstorms Sunday night into Mon evening and
diminishing overnight Mon night into Tuesday morning. A few
stronger thunderstorms possible along with chance of moderate to
heavy rainfall over 1 inch especially eastern/se CWA. Colder air
arrives Mon night and Tuesday. Dry conditions return Tuesday
afternoon thru next Wednesday.


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 600 AM CDT Wed Oct 16 2019

A strong 540 dm 500 mb low over northern lower Michigan early this
morning will deepen to 535 dm as it tracks east to near Niagara
Falls by 06Z/1 am tonight. Broken to overcast stratocumulus clouds
moving south toward I-74 at 11Z/6 am will push south toward SPI
and DEC by mid morning and continue much of the day with ceilings
ranging from 2.5-3.5k ft. Brisk WNW winds to veer NW and increase
to 12-17 kts by 15Z with gusts of 20-25 kts. NW wind to diminish
toward sunset as stratocumulus clouds scatter out during the
evening lasting longest at BMI and CMI. Some mid/high clouds to
stream southeast over central IL by early overnight and diminish
toward daybreak Thu as 1026 mb high pressure over the central
Plains moves into the Ozarks of southern MO and northern/nw AR by
sunrise Thu.





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