028 
FXUS63 KILX 200517
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1217 AM CDT Sat Sep 20 2025

.KEY MESSAGES...

- Daily chances for showers and thunderstorms are expected this
  weekend into the new week. Total precipitation will vary on
  where storms develop, with probabilistic guidance suggesting a 
  30-50% chance for total rainfall amounts over 2 inches.

- Temperatures will stay warm through the weekend then cool closer
  to seasonal normals by the middle parts of next week.

&&

.UPDATE...
Issued at 847 PM CDT Fri Sep 19 2025

Made some minor adjustments to the pop/wx grids for the rest of
the night and into tomorrow morning. Nothing major but did drop
them below chance category. An updated zfp should come out with in
the next 30 mins. 

Auten

&&

.DISCUSSION...
Issued at 231 PM CDT Fri Sep 19 2025

An upper trough spinning over the Northern Plains will slowly work 
into the Upper Mississippi Valley this weekend. Several embedded 
shortwaves will rotate through the main trough, bringing occasional 
chances for showers and thunderstorms through early next week. After 
a brief lull in activity the last few hours, an uptick in coverage 
has commenced this afternoon as a shortwave in eastern MO/southwest 
IL lifts northward. Latest high resolution guidance shows this 
activity pushing north of the area around or shortly after sunset 
this evening. Another uptick in coverage is expected late tonight
after midnight with yet another shortwave. Although most should 
only see light rain during these periods, the 19.12Z HREF LPMM 
shows pockets of 24 hour QPF exceeding 1". 

Higher rainfall chances become focused north of the warning area on 
Saturday as shortwave activity shifts into northern Illinois. 
Precipitation chances increase once again Sunday into Monday (30-
60%) as several subtle shortwaves work through the upper flow. 
Although the entire weekend will not be a washout, the pattern 
warrants carrying at least low-end precipitation chances until the 
details can be refined. Weak shear through the weekend should keep 
the threat for any severe weather low. Temperatures will cool 
slightly each day, with highs by Sunday expected to peak in the 
upper 70s to middle 80s. 

Daily rainfall chances continue through the remainder of next week 
as a stronger upper low dives southeast into the central US, then 
becomes closed off near the middle Mississippi Valley. Upper ridging 
will be in place north of upper low, creating another Rex block over 
the central US. Central Illinois will be on the cooler, wetter side 
of this blocking pattern this time, which is a welcome sight as we 
attempt to ease our drought conditions. Little movement in the 
closed low will result in at least low-end chances for showers and 
storms through the end of next week. Probabilistic guidance has a 30-
50% chance of total QPF through the end of next week, which is an 
increase from previous runs.

NMA

&&

.AVIATION...  (For the 06z TAFs through 06z Saturday Night)
Issued at 1216 AM CDT Sat Sep 20 2025

A slow moving upper low will meander over the Upper Midwest 
through the forecast period with several bands of showers and 
storms expected in the vicinity of this feature. Have very low 
confidence in specific timing at the central Illinois terminals, 
but a few windows of showers and storms will be possible. Outside 
the influence of any precip, light winds and VFR conditions will 
prevail.

Deubelbeiss

&&

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

$$