Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 180735
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
235 AM CDT Mon Sep 18 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 235 AM CDT Mon Sep 18 2017

The weak front that passed through last evening was settling in
extreme southern Illinois early this morning. Just a few lingering
showers near Champaign as of 2 am, though these continue to fade.
Cooler and drier air has settled into the northwest tip of the
CWA, with dew points near Galesburg down to 49 degrees, but still
58 at Peoria.

The drier air will not make much headway into the forecast area,
as the boundary starts heading back north later this morning. An
area of thunderstorms currently over the central Plains will be
moving eastward through the day, and should be approaching west
central Illinois late in the afternoon. Ahead of it, scattered
convection is expected to develop as the front lifts northward.
Have done some significant changes to the PoP trends for today,
and focused the highest values tonight as a shortwave arrives from
the west.

Temperatures are not expected to get quite as warm as yesterday
due to increased cloud cover, but should reach well into the 80s
most areas.

&&

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 235 AM CDT Mon Sep 18 2017

The main theme for the week will be the very warm weather. An
upper ridge over the eastern U.S. will be amplifying during the
second half of the week, as Hurricane Jose off the Atlantic coast
serves as a bottleneck for any eastward progression of systems.
This will keep 850 mb temperature of 16-19C in our area. Highs
near 90 are likely mid week and can`t be ruled out for the
weekend.

With the building ridge, precipitation chances will be shutting
down. Any lingering showers/storms from Tuesday`s upper wave will
be diminishing by evening, then the ridge will start to build in
earnest. The GFS and Canadian models try to edge some
showers/storms from a cold front into areas northwest of the
Illinois River Wednesday night, which may be too aggressive given
the strength of the ridge. At this point, will limit any
mentionable PoP`s with this system to areas northwest of Peoria
Wednesday night.


&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1052 PM CDT Sun Sep 17 2017

Main forecast concern this period will be with the threat for
MVFR or lower cigs/vsbys in the 10z-13z time frame, especially
from CMI to just east of BMI. Forecast soundings continue to show
the potential for a brief period of low cigs along and east of
I-57 early Monday morning with some westward drift possible just
before sunrise. Otherwise, mainly VFR conditions are expected for
the remainder of the forecast period with shower chances increasing
after 21z at PIA and SPI and after 00z at CMI. Confidence on timing
and especially coverage rather low this far out so will handle with
VCTS or VCSH. Light east to northeast winds tonight will become east
to southeast on Monday but speeds even during the day Monday do not
appear to be much of a factor with most TAF sites seeing 10 kts or
less.


&&

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

$$

SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Smith



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