Decatur, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

062
FXUS63 KILX 022314
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
614 PM CDT Wed Jul 2 2025

.KEY MESSAGES...

- Heat and humidity will gradually increase into the weekend. By
Friday, highs will be back in the low to mid 90s with heat indices
around 100 degrees.

- 20% chance of showers and thunderstorms Thursday evening into
Friday morning. More chances arrive late Saturday as a cold front
slides into the state.

&&

.DISCUSSION...
Issued at 246 PM CDT Wed Jul 2 2025

Highs have been in the mid to upper 80s so far today, but that will
change for the end of the week. The temperatures are set to continue
to gradually warm with increasing humidity. Friday and Saturday,
highs will be back in the low to mid 90s with heat indices around
100 degrees.

Mainly, the forecast will be dry through late Saturday, but a 20%
chance for thunderstorms was introduced for tomorrow evening into
Friday morning. A pulse along the ridge with pass north of the
area, and could potentially bring showers and thunderstorms to the
forecast area if it comes further south. <1000 J/kg of MLCAPE and
around 30 knots of shear could support thunderstorm development,
if they can break through the cap. SPC has a marginal risk for
severe weather just half a county to the north of Marshall County.
There is still quite a bit of uncertainty in if they will impact
central IL but didn`t want any possible storms to come as a
surprise.

The 4th of July (Friday) should be dry by the time fireworks are set
to start. By late Saturday, a slow moving cold front will sag across
the forecast area, bringing showers and thunderstorms with it.
Locally heavy rain is looking probable with this wave as PWATs are
showing values of 2.0-2.2 inches. The chance for showers and
thunderstorms will continue into the first half of the new week.
More seasonable temperatures are in store for the new week behind
the cold front.

Copple

&&

.AVIATION...  (For the 00z TAFs through 00z Thursday Evening)
Issued at 614 PM CDT Wed Jul 2 2025

A shortwave trough will bring a period of (VFR) ceilings around
FL120 for the next several hours, however precipitation is not
anticipated (despite light radar returns) due to prolific dry air
in the low levels. Westerly winds will become light and fickle
later this evening, becoming predominantly southwesterly but only
increasing to 5-8 kt late tomorrow morning, when diurnal cu
return around FL050.

Bumgardner

&&

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

$$