Decatur, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

103
FXUS63 KILX 141707
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1207 PM CDT Sun Jun 14 2026

.KEY MESSAGES...

- Beautiful, but cool summertime weather is in store for this
  afternoon into Monday. Highs in the 70 and lows in the 50s.

- After a brief lull, a marginal risk for severe weather returns
  Tuesday, with a 30% risk for severe weather on Wednesday.

&&

.DISCUSSION...
Issued at 252 AM CDT Sun Jun 14 2026

Showers and thunderstorms will slide through central IL into the
morning. They have taken their time to arrive. There still is a
marginal (level 1 of 5) risk for severe weather tonight, mainly for
damaging winds and small hail. By the afternoon, the entire forecast
area should be dry, which will last until Tuesday, as a high
pressure sets up over the region this afternoon. The main focus for
today is the northwesterly winds that will be around 15-20 mph and
gusting up to 25-30 mph. Highs today into Tuesday will be in the
70s, and lows in the 50s. Temperatures through the week will remain
around normal, with highs in the upper 70s to low 80s.

A weak wave/frontal boundary is forecast to move through on Tuesday,
bringing showers and thunderstorms back into central IL. SPC has a
marginal risk for severe weather for eastern IL, east of I-55. The
GFS shows strong bulk wind shear (45-55 knots) but lower MUCAPE
(~1000 J/kg). The hazards of concern are gusty (up to 60 mph) winds
and near severe/severe hail. The storms Tuesday could be strong to
marginally severe during the afternoon into the evening. Uncertainty
exists on how strong the storms could become.

Wednesday looks to be a better day for severe weather and potential
flooding over Tuesday`s storms. SPC has a 30% severe weather risk
over the majority of the forecast area. The better environment looks
to be focused over northern MO and far west-central IL, with the
parameters waning as you go east and with time. However, the LLJ
should be increasing as the QLCS approaches IL. WPC has introduced
an excessive rainfall slight risk for Wednesday. PWATs look to be
around 1.9-2.1 inches. With many rivers/streams already at or near
flood and saturated soils, flooding could be a concern through
Wednesday. Stay tuned for future forecasts as the details become
more apparent into the new week.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1207 PM CDT Sun Jun 14 2026

Breezy northwest winds behind a cold front will continue through
early evening before becoming light and variable overnight ahead of
an approaching surface high. Aside from diurnal cumulus this
afternoon or a passing cirrus Monday, VFR conditions are
expected through Monday.

&&

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

&&

$$

KEY MESSAGES...Copple
DISCUSSION...Copple
AVIATION...NMA