Area Forecast Discussion
Issued by NWS Central Illinois

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000
FXUS63 KILX 211718
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1218 PM CDT Wed Jun 21 2017

.UPDATE...
Issued at 1017 AM CDT Wed Jun 21 2017

Have increased area of slight chance Pops and added a small chance
Pops for a time this morning into midday in the northwest based on
HRRR trends and latest RAP. Area of Precip continues to move into
dry air mass and should gradually weaken, but may hold together
into early this afternoon.

Have also altered temps to match up with current conditions and to
reflect a warmer trend than ongoing package had in place. Have
only made minor changes to highs though given the forecast based
on the 12Z KILX RAOB and the expected influx of clouds from
incoming area of convection.

&&

.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 18Z TAFS through 18Z Thursday afternoon)
Issued at 1217 PM CDT Wed Jun 21 2017

Weak convective cluster moving along and north of I-74 may impact
KPIA to KCMI this afternoon. Cluster has limited low-level moisture
to work with and will cover with VCTS. Any precip that does occur
should be brief.

Latest model suite is slowing progress of frontal system southward
Thursday and is bringing low-level moisture northward associated
with remnants of tropical storm Cindy. MVFR ceilings may be
approaching from the south toward the end of the TAF valid period.
Later forecasts will likely bring these CIGS into at least KSPI
and KDEC.

Otherwise light winds and VFR conditions can be expected through
the valid period.

&&

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

$$

UPDATE...Barker
SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...Barker



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