Decatur, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

308
FXUS63 KILX 202259
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
459 PM CST Sat Dec 20 2025

.KEY MESSAGES...

- Temperatures fluctuate through the weekend. Well above normal
  temperatures are forecast from Tuesday through at least Friday.
  There is a 50-80% chance of temperatures exceeding 65 degrees on
  Christmas Day along and southwest of a Macomb to Casey line.

- Mainly a dry forecast through the week over most of central and
  southeast IL. There`s a 20-40% chance of light showers in
  southeast IL Monday night.


&&

.DISCUSSION...
Issued at 14 PM CST Sat Dec 20 2025

Winds will shift out of the southwest are aiding in the warming
daytime temperatures of highs in the upper 40s to low 50s today. A
dry cold front is expected to pass through this afternoon/evening,
which will swing our winds to a more northerly direction,
introducing some CAA. Tomorrow`s high will be in the mid 30s to low
40s. Tomorrow night, a high pressure system will develop off to our
east, shifting the winds out of the southeast. This will begin our
great warm up for the Christmas holiday. By mid week, temperatures
during the day will be in the mid 50s to mid 60s. Lows tonight and
tomorrow night will be in the 20s, but will also warm to well above
normal for the week.

We will be pushing records on Christmas day. Most of the records are
in the low 60s (61-64 degrees) for our climate sites. There is a 50-
80% chance of temperatures exceeding 65 degrees on Christmas Day,
from the LREF, southwest of a Macomb to Casey line. The NBM shows
the 50-70% chances mainly in our southeastern 6 counties for that
same time.

The forecast is primarily dry, but there are a few weak disturbances
that look to move through that could produce a few sprinkles or
flakes occasionally through the next week. A cold front appears to
move late this week, but should be dry as according to the current
models. We are still several days out from Christmas, so some
forecast elements could still change. We (forecasters) tend to get a
bit skeptical of dry weather when temperatures get into the mid to
upper 60s with dewpoints nearing 60 degrees in December. We will
continue to monitor trends the next week. As of this moment, we
remain positive that Christmas should be a lovely, dry, warm day.

Copple

&&

.AVIATION...  (For the 00z TAFs through 00z Sunday Evening)
Issued at 458 PM CST Sat Dec 20 2025

High pressure currently centered over the Upper Midwest will shift
to central Illinois Sunday morning then to the Upper Ohio Valley
Sunday evening. NW winds will become light and variable as the
ridge moves overhead, then set up out of the SE behind the ridge
axis. VFR conditions are expected through the period.

Deubelbeiss

&&

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

$$