Decatur, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

872
FXUS63 KILX 222252
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
452 PM CST Mon Dec 22 2025

.KEY MESSAGES...

- Well above normal temperatures are forecast through at least
  Friday. South of I-70 has the best (70-100% chance) of
  exceeding 55 degrees Weds, Weds night, and Thurs.

- There`s a 20-40% chance of light showers and/or drizzle in far
  eastern and southeastern IL tonight. Patchy fog could develop
  overnight where precipitation falls this evening.

&&

.DISCUSSION...
Issued at 138 PM CST Mon Dec 22 2025

A weak disturbance lifting up the lower MS River Valley and into the
lower Ohio River Valley this evening could bring a 20-40% chance of
light showers or drizzle to far eastern and southeastern IL
tonight. Some patchy fog is possible overnight in the areas that
potentially see precipitation. Tomorrow is dry as a cold front
moves through. Another low system will move through the region,
bringing a warm front north on Wednesday and it could bring some
light showers and/or drizzle. That warm front practically stalls
out blanketed across central IL. It will wobble south at night,
then back north Thursday. Finally, a cold front will move through
late this week, bringing cooler air back into the area, but
temperatures still look to be above normal.

The extent north that the greater push of warm air can get Wednesday
and Thursday will be determined by how far north that warm front can
get and if the cloud cover can break up enough for the sun to warm
the surface some. It will be pretty cloudy this week from the
multiple disturbances that will move through. The cloud cover will
help nighttime lows to stay warm, but may hinder how high the
daytime temperatures can get. South of I-70 has the best (70-100%
chance from NBM) of exceeding 55 degrees Weds, Weds night, and
Thurs. Chances drop off as you move north from there. We are
monitoring this closely because if the 60+ temperatures can push far
enough north, we will be flirting with record temperatures for both
highs and lows.

Copple

&&

.AVIATION...  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 452 PM CST Mon Dec 22 2025

An area of MVFR ceilings (with breaks for VFR) extends over much
of central IL back into southeast IA. Trends should be for this to
gradually clear from the west this evening, though this is a low
confidence forecast given satellite trends and how models are
handling the cloud field. Another round of MVFR ceilings is
forecast to develop over eastern near 12z and expand west to
include KCMI-KBMI-KDEC. Winds will be around 10 kt or less
through the forecast, initially south, then veering west Tue AM
and northwest during the afternoon.

25

&&

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

$$