Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 210747

Area Forecast Discussion
National Weather Service Lincoln IL
247 AM CDT Wed Jun 21 2017

.SHORT TERM...(Today and tonight)
ISSUED AT 247 AM CDT Wed Jun 21 2017

A weak boundary was extending just north of the I-72 corridor
early this morning. Showers south of it have been persisting a bit
longer than earlier expected, but are on track to be out of the
area by sunrise.

Upper level flow has begun a transition as the ridging over the
western U.S. continues to break down. As this occurs, the boundary
will begin lifting back north as a warm front today, reaching
northern Illinois this evening. Expected MCS development continues
to look to be further north from our area, and have cut back on
the PoP`s tonight to limit them to areas north of Peoria and
Galesburg. In the meantime, isolated afternoon storms should be
less in coverage than the last couple days, mainly near the front
in the northern CWA as well as a residual boundary near I-70. With
the front lifting north, a good chunk of the CWA should reach into
the upper 80s or lower 90s as dew points creep upward into the
upper 60s.


.LONG TERM...(Thursday through Tuesday)
ISSUED AT 247 AM CDT Wed Jun 21 2017

Rain chances Thursday into Friday will be coming in from a couple
different directions. The northern parts of the forecast area will
be influenced by an upper wave which will bring a cold front into
the area late Thursday night, while the southeast CWA sees a surge
of moisture associated with the remnants of Tropical Storm Cindy
after it makes landfall early Thursday. This latter moisture surge
will be most prevalent Thursday night and Friday, as the cold
front drops in from the north with additional moisture. Rainfall
of 3/4 to 1.25 inches may reach as far north as a Flora to
Robinson line, but the bulk of the forecast area should see 1/3
inch or less. Severe-wise, far northern CWA remains in a slight
risk for severe storms, mainly with the front later Thursday
night, although any residual boundaries dropping south from the
MCS could serve as a focus as well.

While temperatures should reach the lower 90s in many areas on
Thursday, a transition to a cooler weather pattern will take place
and persist into early next week. A significant wave rotating
eastward across the upper Midwest early this weekend should
largely stay to our north, but some slight chance PoP`s are
warranted over the far northern CWA Saturday afternoon. While the
grids include some slight chances late Saturday night as well,
this is more uncertain as it is largely based on the 12Z ECMWF
since the 00Z run did not come in past 96 hours. Both the GFS and
Canadian models keep this period dry. Overall though, a period of
dry conditions should prevail through the weekend into early next
week. Temperatures will back off as the broader long wave pattern
arrives, with highs mainly in the mid 70s Sunday and Monday.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1133 PM CDT Tue Jun 20 2017

A few showers lingering near DEC and CMI at 0415z should depart
to the southeast by 06z/1am. Otherwise, a generally weak pressure
pattern across Illinois should help provide quiet weather over
the next 24 hours. Light and variable winds are expected through
sunrise, then winds will be on a steady shift from N to E to SE
during the day on Wednesday. Wind speeds look to prevail below
10kt tomorrow, during the persistent wind shift.

No significant cloud ceilings are expected this TAF period, with
the HRRR suggesting a band of 5-6K FT clouds will develop near the
I-74 corridor around sunrise. Otherwise, SCT150-200 will be the
rule for the majority of the next 24 hours.

A weak shortwave will pass across northern Illinois tomorrow, but
all precipitation looks to remain north of the TAF sites.




SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Shimon is the U.S. government's official web portal to all federal, state and local government web resources and services.