Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 231752
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1252 PM CDT Fri Jun 23 2017

.UPDATE...
Issued at 1045 AM CDT Fri Jun 23 2017

15Z/10 am surface map shows a cold front slipping just south of
I-72 and connected to 1004 mb low pressure west of Litchfield.
Moist dewpoints in the upper 60s to mid 70s from Peoria se while
dewpoints slipping into the upper 50s to mid 60s from Macomb to
Lacon northward. Meanwhile the remnants of tropical storm Cindy
circulation center was just sw of Dyersburg in far western TN at
10 am. Tropical bands of moderate to heavy rains were se of a
Paris to Effingham line with the heaviest rains of 1.5-3 inches
falling in southern Richland and far southwest Lawrence county.
HRRR model capturing this well and shows this band of moderate to
heavy rains diminishing in southeast IL between 17-20Z (noon-3
pm) and most of this convection is southeast of Lawrence county by
late afternoon as cold front pushes through southeast IL during
the afternoon. Far southeast IL could see another 1-2 inches with
locally 2-3 inches into early afternoon and issued a special
weather statement over Richland, Crawford and Lawrence counties.
Flash flood guidance values are fairly high in southeast IL,
around 2.25 inches in 1 hour, 2.75-3.25 inches in 3 hours and
3-3.5 inches in 6 hours so held off on flash flood watch. But
flash flood watches are posted just south and east of these 3
counties. Sunshine appearing nw of the IL river and expect clouds
to continue to decrease from nw to se during afternoon over
central IL as drier air filters in on breezy NNW winds. Highs in
the upper 70s and lower 80s look on track today.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 235 AM CDT Fri Jun 23 2017

2 am surface map shows the cold front located from just north of
Kansas City to just south of Milwaukee. Extensive line of
thunderstorms extends along the boundary, although a few showers
ahead of it northwest of the Illinois River. Further south,
leading edge of the showers associated with the remnants of Cindy
were lifting northward through far southern Illinois, though the
low pressure itself was still over central Arkansas.

The main forecast concerns for the entire 7-day forecast period
are focused on the time frame into about mid afternoon today, as
the cold front quickly pushes southeast. Most of the models have
the front reaching about Champaign and Effingham around 9-10 am,
but a slowdown occurs as the Cindy low lifts into far western
Kentucky by midday. Up until that point, a fairly clean sweep
occurs with the showers and storms as they cross the CWA, quickly
ending behind the front. However, with the added tropical moisture
over the southeast CWA and the slower front, the rain is likely to
persist into mid afternoon, and PoP`s were increased a fair amount
in this area. An inch or so of rain appears likely in areas
toward Olney and Lawrenceville, before the system finally moves
out late afternoon. Despite some decent CAPE`s above 1,000 J/kg in
this area, low level shear along the front is meager, with the
main shear closer to the low. Thus, severe weather is not
anticipated at this time.

.LONG TERM...(Saturday through Thursday)
ISSUED AT 235 AM CDT Fri Jun 23 2017

Cooler and less humid conditions are expected this weekend into
early next week, as a broad upper trough prevails over the central
CONUS. With 850 mb temperatures progged to dip as low as 5-7C
depending on the model, highs in the 70s and lows in the 50s will
prevail. Some stronger waves will swing across the Midwest this
weekend within the trough. Much of the focus will be closer to the
tracks of these waves, but a few showers and storms are possible
as far south as central Illinois by Monday afternoon. Will keep
slight chance PoP`s around 20% going during this period for now.
As the week progresses, the ridge over the western U.S. will break
down and send another surge of warmer air aloft our way. A series
of shortwaves pushing eastward during mid and late week will
result in more robust rain chances.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1250 PM CDT Fri Jun 23 2017

A cold front was pressing southward toward I-70 early this
afternoon and its convection was se of central IL airports. Cold
front to push through southeast IL by 21z/4 pm and breezy north
winds behind cold front over central IL this afternoon with gusts
15-23 kts. Winds to veer WNW and decrease to 5-10 kts after sunset
then increase to 10-15 kts with gusts 15-20 kts after 14Z/9 am
Sat. Clearing line was pushing se to along I-55 early this
afternoon. MVFR broken ceilings at DEC and CMI for about another
hour, then clearing skies with VFR conditions expected through
midday Saturday. A 553 dm 500 mb low over east central
Saskatchewan to dive se into east central MN by 18Z/1 pm Sat and
will keep its clouds and showers north of central IL through
Saturday.

&&

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

&&

$$

UPDATE...07
SHORT TERM...Geelhart
LONG TERM...Geelhart
AVIATION...07


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