029
FXUS63 KILX 101103
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
603 AM CDT Fri Oct 10 2025

.KEY MESSAGES...

- Light showers generating up to a tenth of an inch of rainfall
  will decrease in coverage as they move east this morning. The
  highest chances for measurable rain (15-30%) will be west of
  roughly I-55.

- There is a low (10-15%) probability of a stray shower Monday
  and Tuesday. Otherwise, expect dry and mild conditions through
  at least the middle of next week.

&&

.DISCUSSION...
Issued at 127 AM CDT Fri Oct 10 2025

***** CLOUDY WITH A FEW SHOWERS FRIDAY *****

Early Friday morning, WPC analyzed a cold front extending from
Minnesota southwestward across Nebraska. Ahead of it, a narrow
corridor of warm and moisture advection has brought enough moisture
for the front to spark some isolated showers across Iowa and
Wisconsin. Locally, high pressure has promoted light winds and clear
skies which have allowed temperatures to sink like a rock since
sundown. The forecast for patchy frost remains on track across our
east where dewpoints are in the mid 30s, while cloud cover and
southerly winds will overspread areas west of roughly I-55 before
daybreak - preventing temperatures from getting cold enough for
frost.

CAMs suggest the widely scattered upstream showers will generally
begin a waning trend as they cross the Mississippi River into a
progressively more dry airmass; ILX`s 00z raob, for example,
featured a PWAT of 0.33", which is below the 10th percentile of
climatology (0.40"). The highest chance of measurable rain will be
west of I-55 and especially west of the IL River where HREF, REFS,
and NBM suggest a 15-30% chance. In addition, these showers and
attendant rain amounts will be light given the (1) dry environmental
airmass and (2) lack of instability. HREF and REFS LPMM confine
amounts to under a tenth of an inch. Some guidance, most
aggressively the NAM, indicates potential for drizzle this evening
into tonight as prob cloud ice diminishes, 0-1km mean RH exceeds
85%, and some weak negative (i.e., upward) omega coincide, though
HREF is only advertising 10-20% chances for IFR (<2sm) visibilities
and (<1000 ft) ceilings which yields low confidence.


***** WARM AND PROBABLY (80% CHANCE) DRY SATURDAY ONWARD *****

Tomorrow through Monday, deterministic guidance is in general
agreement that a shortwave ridge of high pressure will expand into
the region from the Great Plains. The drying low levels, lack of
opaque clouds, and a push of warm advection on the ridge`s western
periphery should result in a warming trend with temps standing a 50-
60% chance of reaching 80 by Monday according to NBM.

Increasing uncertainty begins to creep into the forecast by Monday
though, with a handful of solutions bringing a strong enough
shortwave and sufficient moisture into the region to generate a
couple showers between Monday and Tuesday. Looking at the 09.12z
LREF clusters in DESI, one solution (cluster 4) advertises a 20-35%
chance (highest west) for over a tenth of an inch of rainfall on
Monday, while the other 3 outcomes offer sub mentionable (i.e., less
than 15%) probabilities. For now, our forecast sticks with NBM`s
climatology-calibrated 10-15% chances, and in any case we`re
certainly not going to see a drought-busting, soaking rain.

The remainder of the work week, we remain close enough in proximity
to the periphery of the ridge that with a parade of disturbances
attempting to flatten it rain chances are nonzero, but certainly low
(10% or less). Meanwhile temperatures are slated to trend slightly
above normal with forecast highs in the low to mid 70s.

Bumgardner

&&

.AVIATION...  (For the 12z TAFs through 12z Saturday Morning)
Issued at 557 AM CDT Fri Oct 10 2025

A decaying line of showers and a couple thunderstorms will bring a
15-30% chance (highest at PIA) for precipitation mid morning into
early afternoon. Given the proximity of thunderstorms to PIA and
the way model data has been underselling the strength of the
convection, opted to add TSRA in a PROB30 group there from
13-16z. Otherwise, expect low VFR ceilings the remainder of the
day, with a 20-30% chance for drizzle and MVFR/IFR conditions
overnight into Saturday morning. Given the low confidence, opted
to only hint at this potential for now via VCSH and SCT009 in the
TAF.

Bumgardner

&&

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

$$