Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 260153
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
853 PM CDT SUN SEP 25 2016

.UPDATE...
Issued at 853 PM CDT Sun Sep 25 2016

Cold front has passed a Peoria to Jacksonville line and will
continue eastward overnight reaching the Indiana state line around
Midnight. Much cooler temperatures will trail the front as well as
scattered showers as an upper level shortwave moves into the area.
Ahead of the front enough instability lingers east of I-57 that an
isolated thunderstorm will be possible this evening...diminishing
to just areas south of I-70 after midnight. Lows should drop to
the lower 50s west of the Illinois River ranging on up to the
lower 60s south of I-70. Light south winds continue east of I-57
this evening but will switch to westerly later this evening, then
breezy west winds 10-15 mph will continue through the night. Have
updated forecasts for precip and thunderstorm coverage this
evening.

&&

.SHORT TERM...(This evening through Monday)
ISSUED AT 245 PM CDT Sun Sep 25 2016

Scattered showers and isolated thunderstorms were east of a Peoria
to Lincoln to Taylorville line at mid afternoon and tracking
northeast ahead of a prefrontal trof moving into central IL.
Scattered to broken cumulus and mid level clouds was giving partly
to mostly cloudy skies. Temps had warmed back into the mid 80s to
around 90F except in rain cooled areas that slipped toward 80F.
Dewpoints ranged from 62-70F so another very warm and rather muggy
summerlike day. A strong cold front over far eastern IA into eastern
MO will sweep east across IL during late afternoon and evening,
reaching the IN/IL border by midnight. Hi-res models show scattered
convection along and ahead of the cold front into this evening. A
strong upper level trof over the upper Midwest will settle east into
the western Great Lakes and IL by sunrise Monday and keep chances of
showers going overnight especially east of the IL river. Lingered
small chances of convection along and southeast of a Danville to
Effingham line Monday morning and should be dry there too by late
Monday morning as clouds decrease over southeast IL and skies become
sunny by Monday afternoon. Lows overnight range from the lower to
middle 50s over the IL river valley, to the lower 60s near the
Wabash river. Much cooler highs Monday of 69-73F with breezy WNW
winds of 10-20 mph and gusts in the 20s.

.LONG TERM...(Monday night through Sunday)
ISSUED AT 245 PM CDT Sun Sep 25 2016

Main concern shifts to the track of the upper low this week. There
is good agreement from Monday night through Wednesday, as the low
tracks from north of Lake Superior to Ohio/Kentucky Wed evening.
Beyond that, solutions diverge. The ECMWF keeps the low just east of
Illinois drifting it south into Tennessee through Friday then
retrograding it to the NW toward IL next weekend. The Canadian and
GFS both slowly drift the upper low toward the East Coast Thursday
into Saturday.

The overall affect on sensible weather will be a slight chance of
showers in NE Vermilion County Tuesday night as all 3 models and the
NAM show the upper low reaching its closest point to our CWA.
Another item of note will be gusty winds on Tuesday as deep layer NW
flow mixes to the surface providing 25-30 mph gusts.

Beyond that, the EC solution would point toward increased rain
chances Wednesday and again next weekend, while the Can/GFS solution
would be mainly dry with increasing temperatures the rest of the
week. The consensus blend shows a continued dry forecast for the
last half of the week and next weekend, and will not alter that
trend with this update.

The chilly air mass will provide below normal temperatures for the
first portion of the extended, with lows in the upper 40s Mon night
and Tues night, and possibly Wed night. High temps Tuesday will be
similar to Monday, in the upper 60s N of I-74 and low 70s elsewhere
in our CWA. Beyond that, it appears we should expect a slow warming
trend of a couple degrees each day for both highs and lows. Even
with that warming, highs will only climb to the mid to upper 70s
next Sunday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 632 PM CDT Sun Sep 25 2016

A cold front will be near KCMI at 00Z and continue eastward
through the night. Chances for thunderstorms will diminish rapidly
behind the front and are too low for mention in 00Z TAFs.
However...as an upper level trough continues to approach from the
west another area of scattered showers and ceilings around 5000
feet AGL will affect the central IL terminals from around 2-4Z
until 9-12Z. Winds turning W-WNW by 01Z with gusts 15-20 kts this
evening. WNW winds 8-15 kts continuing through the period. Gusts
diminishing late in the night, then returning 22-25 kts after 16Z
Monday.


&&

.ILX Watches/Warnings/Advisories...
NONE.
&&

$$

UPDATE...Onton
SHORT TERM...07
LONG TERM...Shimon
AVIATION...Onton


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