254
FXUS63 KILX 061114
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
614 AM CDT Sat Jun 6 2026

.KEY MESSAGES...

- Isolated to scattered showers and thunderstorms are possible
  this weekend over central IL, mainly north of I-70. A few
  storms could have the potential to become strong to severe,
  posing a risk for locally heavy rain of 1-2 inches, large
  hail and damaging winds.

- More widespread showers and thunderstorms are expected over
  central and southeast IL Sunday night through Monday night.

- Expect a warm and muggy conditions today with feel-like
  temperatures climbing into the lower 90s this afternoon.

- A stronger warming trend arrives Tuesday through Friday,
  pushing afternoon heat index values 95 to 105 degrees.

&&

.DISCUSSION...
Issued at 330 AM CDT Sat Jun 6 2026

Radar mosaic shows scattered showers/thunderstorms over northern
parts of IL/IN into southern Iowa and northern MO. Over IL this
developing convection was north of a Macomb to Peoria to
Kankakee line and tracking eastward. This convection aided by a
WSW 25-40 kt low level jet (strongest winds ne of central IL
over southern Great Lakes) and tropical PW values of 1.4-1.7
inches over much of IL. Unstable air mass over northern IL with
MLCAPES of 1800-2500 j/kg from I-74 north. Bulk Shear values
were less than 25 kts over central IL and 30-45 kts from I-80
north, over northern IL. The 08Z/3 am surface map shows a cold
front over southeast WI into northern Iowa and southeast
Nebraska. SW winds and increasing clouds giving mild temps in
the low to mid 70s (warmest from I-55 west). Dewpoints were in
the lower to mid 60s in east central and southeast IL and upper
60s to near 70F from Highway 51 west.

The 06Z and 07Z HRRR show scattered convection north of Peoria
and lifting through early this morning and mostly existing CWA
by mid morning as low level jets pushes further ne of central IL.
A few strong cells with gusty winds along with locally heavy
rainfall possible early this morning with this convection mainly
north of PIA and BMI next few hours. Otherwise an outflow
boundary lingering over northern CWA to see scattered convection
develop near it during this afternoon in unstable air mass (but
weak wind shear), especially during mid to late afternoon
initially north of a Rushville to Lincoln to Paris line. But
convection chances to shift further south into central IL during
this evening but generally staying north of I-70 into tonight.
SPC Day1 outlook has marginal risk of severe storms this
afternoon/evening north of an Effingham to Robinson line for
damaging winds and large hail. The HREF LPMM also shows a few
pockets of 1-2 inches north of I-74 early this morning and north
of highway 36 this afternoon/evening. Muggy today with very
warm highs in the upper 80s with afternoon heat indices in the
lower 90s. Lows overnight in the upper 60s, with se IL around
70F.

The main synoptic front will move into northern IL this
afternoon/evening, and remain north of central IL on Sunday.
Best convection chances tonight into Sunday will be over
northern CWA closer to this front and over the MS river valley
late Sunday afternoon as system wx system approaches from west
Texas. The weak cutoff 500 mb low over west Texas to open up
into a mid level trof as it moves over IA/MO overnight Sunday
night and into IL Monday afternoon. Deeper tropical moisture to
lift into IL ahead of this system Sunday night and Monday, with
more widespread convection moving eastward over IL during Sunday
night and continues Monday before diminishing from the west
overnight Monday night into Tue morning. NBM has 70-90% chance
of over 1 inch of rain over CWA Sunday night thru Monday night.
Highs Sunday mid to upper 80s and low to mid 80s Monday. Chances
of showers and thunderstorms lingers on Tue and Tue night especially
in eastern IL.

Upper level ridging into IL Tue/Wed to return higher heat and
humidity to the area during mid/late week. Highs Tue in the
upper 80s to around 90F and 90-95F Wed-Fri (warmest over the IL
river valley). Dewpoints in the low to mid 70s to give afternoon
heat indices of 95-105F from Tue thru Friday. This will be our
longest heat wave so far this season and be weather aware of
this high heat and humidity. The ECMWF and GFS models showing a
frontal boundary pushing se into IL Thu night and to bring more
chances of convection. Though most days upcoming week we have at
least slight chances of convection in tropical airmass.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 614 AM CDT Sat Jun 6 2026

Cluster of thunderstorms has been sliding just north of the
KPIA-KCMI corridor early this morning. An associated outflow
should help trigger additional storms later today, but timing
and placement is still in flux. Thus, PROB30 mentions are the
best option until trends become more obvious later today.

Southwest winds will average about 10 knots much of the day,
before dropping to less than 5 knots early in the evening.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

KEY MESSAGES...07
DISCUSSION...07
AVIATION...Geelhart