839
FXUS63 KILX 021915
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
115 PM CST Sun Nov 2 2025

.KEY MESSAGES...

- Breezy winds on Monday and Tuesday combined with afternoon
  relative humidity values near 30% will lead to increase risk of
  fire spread. Use caution if burning.

- Above normal temperatures are expected this week, with highs in
  the 60s to near 70.

- The next rain chance is Thursday evening into Friday (30-60%) as
  a cold front moves through the region. Rainfall amounts are
  unlikely to exceed a half inch (just a 10-20% chance of more).

&&

.DISCUSSION...
Issued at 109 PM CST Sun Nov 2 2025

The upper low that brought scattered showers to central IL has
shifted to the TN Valley, located over central TN as of
1230pm/1830z. A broad sfc pressure ridge was situated over the
mid- MS Valley, and will gradually shift SE during the early parts
of this week. The storm track will largely be focused north of
the central IL this week, with occasional sfc lows shifting across
the upper Midwest.

This synoptic pattern will produce a persistent southerly
component to the wind, which will be breezy at times this week,
resulting in above normal temps. Forecast highs are in the 60s
each day this week, and could approach 70 degrees on Tues (20%
chance near the IL River Valley) and Wed (20-40% chance south of
I-72). Normal high temperatures for early November are in the
upper 50s. The forecast highs for this week are still well shy of
record temps, which are around 80 degrees. Precip chances are very
low through the daytime hours on Thurs.

*** FIRE WEATHER ***

With a relatively quiet forecast over the next few days, the
primary forecast concern is the fire weather conditions. Breezy
winds are expected both Monday (with northwesterly gusts generally
25 mph but up to 30 mph at times, especially north of I-74) and
Tuesday (out of the south). For Tuesday, the ensemble mean gust is
around 30 mph, with a 20-40% chance for gusts to 40 mph east of
the IL River. Dewpoint forecasts have also trended drier, and
that`s before adjusting to account for a common NBM moist bias in
these drier regimes. After adjustments, the forecast minimum RH
values for Monday are in the 25-35% range. The RH forecast is less
certain on Tues. In response to lee cyclogenesis over the north-
central Plains, southerly flow will advect a plume of `higher`
moisture air (dewpoints in the 40s) northward into central IL. The
exact timing of this moisture plume will impact the fire weather
conditions. Some models, like the 02.12z NAMNest, keep dewpoints
in the low/mid 30s along the I-74 corridor until late Tues
afternoon.

The "Hot Dry Windy Index" (HDWI), which utilizes the GEFS, shows
most ensemble members with values between 50-100 on Monday (above
the 50th percentile). The values increase further on Tuesday (at
least in locations near/north of I-74 where the moisture plume
arrival is slower), with a majority of members above the 75th
percentile, indicative of increasing fire weather concerns. The
conclusion of most harvest activities should help limit the field
fire potential. It may be best to avoid burning yard waste on Mon-
Tues, or if burning to do so with great care to avoid unwanted
fire spread.

*** LATE WEEK SYSTEM ***

A late week cold frontal passage remains on track to be our next
widespread precip chance (40-60%). The most likely timing still
appears to be Thurs night into Fri, although this could still
fluctuate in the coming days. The diurnal timing will be key to
severe storm potential. The latest Grand Ensemble depicts marginal
thermodynamics (250-500 J/kg of MUCAPE), but perhaps just enough
instability to support a severe threat given 40 kts of deep layer
shear. Given the linear forcing and forecast hodographs depicting
fairly unidirectional low level shear, the potential for severe
wind gusts would be the primary concern. Machine learning (CSU)
and AI- NWP- based (NCAR) outlooks are muted, with some showing
less than a 5% chance in all areas and others showing a 5-15%
chance only in areas near/east of I-57 on Friday. There was no
meaningful change to the rainfall outlook, with just a low chance
(10-20%) of exceeding a half inch.

A clipper-style shortwave progged to swing through on Sat/Sat
night will offer another chance for light rain (20-30%).

Erwin

&&

.AVIATION...  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1152 AM CST Sun Nov 2 2025

Some scattered diurnal Cu have started to blossom around 2.5 kft,
but bases are anticipated to rise to around 4 kft by early
afternoon. Aside from a low chance of brief MVFR ceilings
associated with this diurnal cumulus, VFR conditions are expected
through the period. Southwesterly winds today and tonight will
turn northwesterly Monday morning. Scattered mid/high clouds will
filter through tonight/early Monday.

Erwin

&&

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

$$