Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 261125
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
625 AM CDT TUE APR 26 2016

.SHORT TERM...(Today)
ISSUED AT 335 AM CDT Tue Apr 26 2016

Weak cold currently stretching from northwest Indiana southwest
through our far northern counties into northeast Missouri will slide
south across the forecast area today. Convection has had a hard time
developing along the boundary overnight due to weak convergence and
stronger lift further north with the surface low. Short term models
suggest other than some isolated showers along the southward moving
boundary, the better threat for showers and thunderstorms will be
associated with shortwave energy now pushing through central Kansas.
Convection has already started just ahead of that feature well to
our west with the stronger convection progged to shift east and
affect our southeast counties this afternoon.

Looks like a fairly sharp cutoff to the precip along and north of
Interstate 74 where the lower POPs will be today, while areas south
of I-72 will have the higher rain threat this afternoon. Surface
based capes of around 2500 J/Kg were noted south of I-72 this
afternoon, although 0-6km shear values were not much higher than 25
kts during this same time period. Hail and gusty winds will be
possible over southeast Illinois with this cluster of storms this
afternoon. With the frontal boundary shifting into southeast
Illinois later today, will have a rather large temperature gradient
this afternoon with forecast highs ranging from around 70 over our
far northern counties, to the lower 80s over extreme southeast
Illinois.

.LONG TERM...(Tonight through Monday)
ISSUED AT 335 AM CDT Tue Apr 26 2016

Forecast really is not changing much in this round, with the
exception of maybe building a bit of a break into the evening hours
without precip.  However, the deep low spinning out over the Plains
and developing storm system will slowly spread rain/thunder into the
region after midnight especially...along a developing warm frontal
feature.  The surface low remains out to the west for Wednesday and
is slow to progress with the deep low over eastern Canada/NE CONUS.
Much of Central Illinois remains in the warm sector with a potential
for some persistent and good rain Wed-Wed night along...up to an
inch or so. Low slow to move out Thursday  as the rain comes to an
end briefly with a break before the next wave ejects out of the SW
across the Midwest for the weekend.

Rain chances return for Friday night through the weekend with a
similar setup happening again.  Some variability in the
tracks/strength of the sfc system.  The ECMWF is initially more well
developed with a classic low...but both the European and the GFS get
a messier look by the end of the weekend, with the system shearing
out over the Ohio River Valley and slowing any progression.  Either
way, next weekend looks wetter than not.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 615 AM CDT Tue Apr 26 2016

Patchy MVFR cigs possible for a brief time early this morning,
then we will have to watch the IFR and LIFR cigs over northeast
Illinois, which are currently tracking southwest and may affect
our northern TAF sites later this morning. A band of showers and
thunderstorms looks to affect areas just south of KSPI, KDEC and
KCMI this afternoon but will include VCTS to cover for the potential
that some of the TSRA activity may affect them at or just after
18z. Last several runs of the short term high res models continues
to suggest the stratus deck shifting south-southwest out of
northeast Illinois will stay just north of our TAF sites this
morning. None of the forecast soundings indicate any low level
stratus at our sites even this evening as a northeasterly flow
builds in across the area. Surface winds ahead of the front will
be southwest to west, and then will shift into the northeast
this morning at 8 to 15 kts, but increase from the northeast to
between 10 and 15 kts tonight.

&&

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

$$

SHORT TERM...Smith
LONG TERM...HJS
AVIATION...Smith



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