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Area forecast discussion 
National Weather Service Lincoln Illinois
1138 PM CDT Wednesday Oct 26 2016

issued at 900 PM CDT Wed Oct 26 2016

Cold front has pushed eastward past the Illinois River this
evening. Current timing suggests this feature should reach the
Indiana state line over the first few hours after midnight.
Showers tapering off to drizzle ahead of the front transitioning
to widespread stratus cloud cover behind the front. Isolated
thunderstorms east of I-55 have tapered off over the past few
hours and given the diminishing upper level support plan to pull
all mention of thunder out shortly. Lows should reach the mid 40s
most areas I-55 westward ranging up to the low 50s I-70 southward.


Short term...(this evening through thursday)
issued at 310 PM CDT Wed Oct 26 2016

Moisture channel imagery still shows upper wave tracking slowly
east over eastern Iowa. This is dragging the surface low to the east
over northern Illinois. Cold front over southeast IA, still moving to the
east and will be crossing through region overnight. With the
eastward movement of the front, low clouds will flow into the region
ahead of the front. Clouds with ample moisture will remain in the
region overnight to midday before slowly improving. As for the
rainfall, showers and storm band from northern Illinois to MO has been
slowly moving east through the day. This trend will continue, and
with limited instability and weak forcing, rain will be mostly
showers with some scattered embedded storms, that will last through
the evening, before exiting the area.

Long term...(thursday night through wednesday)
issued at 310 PM CDT Wed Oct 26 2016

High pressure will start to push off to our east Thursday night into
Friday morning allowing a southerly flow to develop over the
forecast area. Coolest temperatures will be across the east by
Friday morning closer to the surface ridge axis. Further west,
looks like a quick drop in temperatures Thursday evening and then
more or less a steady temperature regime will set up overnight as
the south winds build in.

Gusty southerly winds on Friday ahead of our next weather system
will help drive afternoon temperatures well above normal again
with readings in the lower to middle 70s. A relatively mild night
for Friday night as southerly winds hold up through a good portion
of the night as a weak cold front settles south into far southern
Wisconsin or northern Illinois by Saturday morning. Saturday looks
to be our warmest day just ahead of the front with afternoon
temperatures soaring well into the 70s with an 80 possible over
southeast Illinois Saturday afternoon.

Models showing some differences with respect to how quickly the
boundary will shift into southern Illinois with the latest European model (ecmwf)
model slower with the southward push. Weak isentropic lift will
start to develop to our south Saturday night/Sunday morning, at
least if the GFS forecast is correct, with models also indicating
a weakness in the flow aloft tracking across the northern plains.
Forecast soundings continue to depict a rather dry atmosphere in
place across our area, but the combination of the weak isentropic
ascent along and to the north of the frontal boundary and forcing
associated with the mid level shortwave to our north may be enough
to produce some sprinkles or light showers across our north and
east later Saturday night into early Sunday.

Weak high pressure will then settle across the region Sunday night
into early Monday before another fairly significant shortwave tracks
int the plains early next week helping to pump up the ridge over the
central U.S. This should bring a return to well above normal
temperatures early next week with some of the ec guid indicating
low 80s possible Monday afternoon as a gusty southerly wind
develops across the forecast area. Really no sign of any
significant buckling in the flow across Canada as the main belt of
westerlies stays north keeping our temperatures warm through the
end of October.


Aviation...(for the 06z tafs through 06z Thursday night)
issued at 1138 PM CDT Wed Oct 26 2016

IFR ceilings affecting most central Illinois terminals late this evening
as Post cold-frontal stratus cloud cover moves across the area.
Upstream surface observations indicate ceilings will rise slightly
into MVFR category through early morning. Expecting daytime
heating and high pressure building into the region will allow
ceilings to gradually lift and scatter out in the late morning
through afternoon. Winds nw8-14 kts gradually diminishing through
00z then becoming light and variable.


Ilx watches/warnings/advisories...



short term...goetsch
long term...Smith

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