Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 221154
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
554 AM CST Sun Jan 22 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 344 AM CST Sun Jan 22 2017

Areas of dense fog have spread southward almost to the I-72 corridor
this morning as upper level cloud has remained minimal and allowed
surface cooling to take place. With temperatures several degrees
warmer and more mid-upper level cloud south of I-72 anticipate the
dense fog should not spread there...however some models spread low
visibilities as far south as I-70 so may need to make later
adjustments to the dense fog advisory...so far issued to just north
of I-72 until 11 a.m.

Other main feature today is the strong low crossing eastward through
the southern Plains. Models had been advertising precipitation
spreading into central IL the past few days but with the low staying
a bit farther south than anticipated have had very little
shower/virga activity this far northward and have trimmed PoPs for
today/tonight in accord with latest model guidance. Chance category
mainly I-72 southward today/tonight in the morning forecast package.

Northerly winds increasing today due to the influence of the
southern Plains low to the south will bring cooler highs ranging
from the upper 40s to lower 50s along I-74 to the upper 50s south of
I-70, followed by lows tonight in the mid to upper 30s over central
IL, and lower 40s south of I-70. North winds should become quite
breezy afternoon through tonight, 15-20 mph south of I-72 with
higher gusts.

.LONG TERM...(Monday through Saturday)
ISSUED AT 344 AM CST Sun Jan 22 2017

Quiet weather returns to central/southeast IL from Monday through
Tuesday. Strong surface and upper level low pressure over south
central OK tracks eastward into the western Carolinas by sunrise
Monday and turns up toward the southern New England coast by Tuesday
afternoon. Meanwhile an upper level ridge will build into IL and the
MS river valley by sunrise Tue, keeping fair weather with above
normal temps. Have a slight chance of light rain near the IN/IL
border Monday morning mainly early, while brunt of rain showers will
be east of IL over IN/OH and central/eastern KY. Cooler highs Monday
in the low to mid 40s with upper 40s near Lawrenceville with mostly
cloudy to overcast skies. Lows Monday night in the lower 30s, with
mid 30s near the Wabash river. On Tue afternoon have a slight chance
of light rain over Knox and Stark counties, where mostly cloudy
skies, while partly to mostly sunny skies in southeast IL. SSE winds
bring a bit milder temps on Tuesday, with highs of 45-50F, mildest
from Jacksonville to Lawrenceville sw.

A storm system off the Oregon coast is forecast to track eastward
into northeast KS by 18Z/noon Tue and move across northern IL during
Tue night. Models differ with track and speed of low pressure and
stayed close to consensus with a track of low pressure passing
just north of CWA Tue night. GFS and ECMWF are similar with
further north track of low pressure, though GFS is 6 hours quicker
than ECWMF. NAM and GEM have low pressure tracking further south
across central IL, though NAM is about 9 hours quicker than GEM.
Increase pops to likely over far northern CWA Tue night with
chance pops just north of I-72 while keeping southeast IL dry.
Warm enough for just rain chances Tue night with areas just north
of CWA having rain mix with sleet late Tue night. Lows Tue night
range from mid 30s nw of IL river, to the lower 40s in southeast
IL. Highs Wed range from lower 40s nw of Lincoln, to around 50F in
far southeast IL by Lawrenceville. Continued chances of light rain
over central and especially northern CWA Wed while dry in
southeast IL. Could see a mix of light rain/snow and possible
sleet nw of IL river Wed morning but no accumulations. Cooler air
to usher in during Wed night on back side of storm system, and
have precipitation gradually changing to light rain/snow or even
just light snow from nw to se during Wed night over central IL,
while keeping southeast IL dry. Cooler lows Wed night in the upper
20s to near 30F from I-72 north, and lower 30s south of I-72.

A large upper level trof digs across the Midwest and Great
Lakes/Ohio Valley from Wed-Fri returning temps closer to normal
Thu/Fri. Could see a chance of light snow showers or flurries Thu
especially ne CWA, then this shifts further ne by Friday though low
clouds likely linger. Dry and seasonably cold wx expected Fri/Sat.
Highs Thu in the mid to upper 30s, with Galesburg just above
freezing. Highs Friday and Saturday in the low to mid 30s. Lows Thu
night thru Sat night in the low to mid 20s, with some upper teens nw
of the IL river Fri night.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 554 AM CST Sun Jan 22 2017

Dense fog affecting KSPI-KBMI northward this morning, with
expansion of fog area possible to KDEC-KCMI until 15Z. Fog should
diminish by midday, although low ceilings will struggle to improve
beyond MVFR category. Slight chance for showers will develop as a
storm system moves across the southern states, but coverage over
the local terminals should be too low to go above a VCSH mention
at this time. Winds north through the period, becoming
increasingly breezy through the evening today, with 10-15 kt wind
speeds and higher gusts developing.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 11 AM CST this morning for ILZ027>031-
036>038-040>043-047-048.

&&

$$

SHORT TERM...37
LONG TERM...07
AVIATION...37



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