606
FXUS63 KILX 312352
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
652 PM CDT Sat Oct 31 2026

.KEY MESSAGES...

* Isolated to scattered (20-40%) showers will continue through
  Sunday afternoon. Rainfall under a tenth of an inch is most
  likely with isolated pockets around a quarter inch.

* Gusty winds arrive Tuesday with a 40-60% chance for wind gusts
  to exceed 40 mph.

&&

.DISCUSSION...
Issued at 158 PM CDT Sat Oct 31 2026

This Weekend...
Surface high pressure remains centered over the lower Great
Lakes this afternoon, while aloft, an expansive ridge stretches
from the Southeast CONUS to the Canadian Rockies. Meanwhile, a
deep upper low is positioned off the Pacific Northwest coast.
Water vapor imagery shows a series of shortwave troughs buckling
the upper ridge as they lift towards and across the mid-
Mississippi Valley. Isolated to widely scattered showers will
persist across central Illinois ahead of the first wave this
afternoon and evening, lifting into northern Illinois tonight. A
second wave will bring another round of showers primarily south
of I-72 late tonight.

Weak low-level lapse rates and dry air below 700 mb may yield
more virga than measurable rainfall today and tonight. HREF mean
24-hour QPF averages under 0.10 inches through Sunday morning,
though LPMM guidance indicates isolated swaths up to 0.25 inches
are possible within heavier showers. Weak instability (<100
J/kg) and low equilibrium levels preclude thunder mentions
through tonight. Lingering showers Sunday morning will remain
light, tapering off from the west by Sunday afternoon as the
trailing shortwave clears and upper ridging rebuilds. Despite
cloud cover and light rain, temperatures remain above normal
with highs in the 60s, reaching the lower 70s south of I-70.

Early Next Week...
A pair of potent mid-level shortwaves/closed H5 lows will dig
into the western CONUS early next week--one tracking across the
Intermountain West and another across the Canadian Rockies.
Model guidance continues to exhibit spread regarding the
interaction and phasing of these waves, leading to variance in
surface patterns for the mid-to-late week period. Nevertheless,
broad mid-level height falls over the Rockies will induce
surface cyclogenesis over eastern Colorado early in the week.

The surface low is forecast to deepen as it lifts into the
Upper Midwest Tuesday, though model disparity increases
regarding system track and intensity. Stronger solutions favor
breezy to windy conditions across central Illinois on Tuesday;
NBM probabilities for wind gusts exceeding 40 mph range from
40-60% across a good portion of the area. Warm advection ahead
of the system will push highs into the mid 70s Tuesday
afternoon.

Late Next Week...
A cold front associated with the elongated surface trough will
cross central Illinois in the Wednesday to Thursday timeframe,
with timing trending slightly faster in recent model suites.
Temperatures well into the 60s ahead of the boundary will fall
back into the 50s post-frontal. The frontal passage will signal
the end of widespread precipitation, though lingering low-level
cyclonic flow and cold air advection may maintain stratocumulus
cover along with a few light sprinkles into late week.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 652 PM CDT Sat Oct 31 2026

An upper-level disturbance currently near KMCI continues to
pivot moisture northeastward into central Illinois early this
evening. While light radar echoes have been plentiful,
measurable precip has been scant...with mostly just sprinkles
reported. Ceilings will initially be 8000-12000ft, but will
gradually lower to around 5000ft late this evening into the
overnight as the atmosphere slowly moistens from the top-down.
Most CAMs suggest a more concentrated area of showers over
central/southern Missouri will gradually work its way into the
area late tonight into Sunday morning. Have therefore gone with
PROB30 groups for showers at all terminals. The most recent
HRRR/RAP continues to indicate a slower lowering of ceilings on
Sunday, now keeping MVFR conditions mainly S/SW of the TAF sites
until late afternoon or evening. As such, have only included
MVFR at KSPI/KDEC after 20z.

&&

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

&&

$$

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