102
FXUS63 KILX 012340
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
540 PM CST Sun Nov 1 2026

.KEY MESSAGES...

- Strong south winds will develop Tuesday, with a 50 to 70
  percent chance of wind gusts exceeding 40 mph across central
  Illinois.

- Widespread rain arrives Tuesday into Wednesday, averaging
  around 1 inch across the region with a 10 percent chance of
  localized amounts reaching up to 2 inches.

&&

.DISCUSSION...
Issued at 146 PM CST Sun Nov 1 2026

NEAR TERM /THIS EVENING THROUGH MONDAY/...
A shortwave trough embedded within broader upper-level ridging
continues to push across central Illinois this afternoon,
generating scattered showers. As this wave shifts east into
Indiana by late this afternoon and early evening, precipitation
coverage will diminish in its wake. However, mid-level warm air
advection (WAA) will intensify this evening and overnight in
response to a deep upper trough digging over the Intermountain
West and driving cyclogenesis over the Front Range of the
Rockies. Weak isentropic ascent atop a shallow moist layer of
low stratus may squeeze out patchy drizzle overnight into Monday
morning.

SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
A pair of potent mid-level shortwaves--one situated over the
Four Corners region and another over northern Saskatchewan early
Monday morning--will drive renewed precipitation chances
through the first half of the work week. Model guidance has
converged into better agreement regarding the evolution and
degree of phasing of these waves through at least Thursday. A
slow-moving surface low will lift from eastern Colorado early
Monday into the Upper Midwest Tuesday into Wednesday.

Synoptic forcing remains somewhat mixed on Monday as central
Illinois sits squarely beneath the upper-level ridge axis with
neutral mid-level height tendencies offset by continued low-
level WAA. This may prove sufficient for isolated light rain or
drizzle through the day Monday, though QPF will be minimal. NBM
mean 24-hour QPF remains under 0.10 inches Monday through Monday
night, with many dry hours anticipated throughout the day.

As the surface low occludes and meanders over the Upper Midwest
Tuesday into Wednesday, an attendant cold front will approach
and cross central Illinois. A tightening southerly pressure
gradient will yield strong, gusty winds on Tuesday. NBM
probabilities for wind gusts exceeding 40 mph range from 50-70%
across a significant portion of the CWA. Thermal advection ahead
of the boundary will push high temperatures into the 70s
Tuesday afternoon. Breezy conditions persist into Wednesday,
easing slightly as the frontal trough approaches, with
probabilities for gusts exceeding 30 mph hovering around 50%.

Concurrently, a solid band of showers with embedded thunder
will sweep across the region Tuesday into Wednesday. NBM 48-hour
mean QPF through Wednesday night is approximately 1.00 inch
area-wide, while 90th percentile ensemble guidance indicates
localized totals up to 2.00 inches. Instability remains a
primary limiting factor for severe potential; GFS soundings
reveal meager pockets around 50 J/kg MUCAPE, keeping overall
severe risk low along the front.

LONG TERM /THURSDAY THROUGH SUNDAY/...
Frontal passage will signal an end to widespread precipitation
late in the week as the surface low gradually fills and tracks
east across the Great Lakes. Lingering low-level cyclonic flow
and wrap-around moisture within post-frontal CAA will maintain
stratocumulus clouds along with isolated sprinkles or light
showers Thursday and Friday. Highs late week will cool into the
50s in spots. GFS and ECMWF suggest another fast-moving
shortwave may clip the region over the weekend, though details
remain uncertain. NBM currently maintains a baseline 15-20% PoP
for Sunday.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 540 PM CST Sun Nov 1 2026

VFR conditions prevail at most of the central Illinois terminals
late this afternoon: however, IFR/MVFR ceilings are poised just
upstream along/southwest of a KGBG...to KSPI...to KMTO line.
The lower clouds will gradually work their way northward across
the remainder of central Illinois as the evening progresses. Obs
across southeastern Missouri into southern Illinois show widespread
IFR clouds and patches of reduced visbys in drizzle...and these
conditions will gradually overspread the KILX CWA tonight into
Monday morning. Based on the HRRR/RAP, have introduced IFR
ceilings and drizzle at KSPI by 04z...then further north to the
I-74 terminals by 06z. Winds will initially be SE at around
10kt, then will become S/SE and increase to 10-15kt with gusts
over 20kt toward midday Monday. Thanks to the increased winds,
enough atmospheric mixing will occur to bring an end to any
lingering drizzle and gradually improve ceilings to MVFR by
Monday afternoon.

&&

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

&&

$$

KEY MESSAGES...Deubelbeiss
DISCUSSION...Deubelbeiss
AVIATION...Barnes