504
FXUS63 KILX 161101
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
501 AM CST Sun Nov 16 2025

.KEY MESSAGES...

- This afternoon, the combination of low (17-25 percent) relative
  humidity and northwest winds gusting to 20 mph will result in
  elevated fire danger in east-central and southeast IL.

- The next chance (60-75%) for precipitation arrives Monday into
  Tuesday. This will do little to aid the ongoing drought
  conditions, with only a 10-30% chance for more than a half inch
  of rainfall.

- A better opportunity for widespread beneficial rainfall arrives
  Thursday into Friday. There is a 30-50% chance for rain amounts
  greater than 1 inch.

&&

.DISCUSSION...
Issued at 206 AM CST Sun Nov 16 2025

***** MARGINAL FIRE WEATHER TODAY, COLD TONIGHT *****

In the wake of a cold front which crossed the area yesterday
afternoon, continued cool advection will keep temperatures closer
to seasonable normals with afternoon highs in the low to mid 50s
today. As surface high pressure nudges towards the area from the
Upper Midwest, winds will ease later during the afternoon, but
there should be enough of a gradient for some gusts around 20 mph
in east- central IL for a few hours around lunchtime. Combined
with dry air aloft mixing to the surface for relative humidity
values of 17-25%, this will result in some marginal fire weather
conditions, so we`d recommend extra caution with any burning.

HREF suggests less than a 10% chance of cloud cover from midnight to
6am tomorrow morning east of the IL River, and with light-calm
surface winds and dewpoints in the teens to low 20s we`ve got a
strong suspicion NBM mean isn`t cool enough. We blended to the HRRR
and Canadian to bring Monday morning low temperatures down by 2-4
degrees; forecast lows now range from the mid 20s to around 30,
coldest in east-central IL.

***** SHOWERS TOMORROW EVENING INTO EARLY TUESDAY *****

Global deterministic models are in general agreement that a
shortwave trough drifts across the Midwest tomorrow night into
Tuesday, bringing central and southeast IL a 60-75% probability
for light rain. The warmer and more humid airmass may lend itself
to a few rumbles of thunder south of a roughly Rushville to Paris
line tomorrow evening through the overnight as the EPS (ECMWF
ensemble) mean advertises 400-600 J/kg elevated MUCAPE which
soundings suggest runs from roughly 750mb-300mb - right through
the HGZ (for charge separation). Unfortunately, it appears
unlikely that we`ll receive enough rainfall to make much
difference to the ongoing severe (moderate) drought north (south)
of I-70 where NBM gives only a 10-25% (20-35%) chance for more
than a half inch.

Behind that system, Wednesday is shaping up to be a rain-free and
mostly sunny day as northeast winds advect a drier low level
airmass into the Prairie State. It should also be a bit warmer, as
modest ridging expands northward into the Midwest for 500mb
heights solidly in the 570s dam (per LREF mean); forecast highs
range from the mid-upper 50s along I-74 to mid 60s south of the
I-70 corridor.

***** RAINY END TO THE WORK WEEK *****

Global models and their respective ensembles are in general
agreement that a closed low in the Desert Southwest will phase with
a northern stream shortwave, and subsequently move through the
Mississippi Valley/Midwest Thursday into Friday. Due to the complex
interactions between this feature and any disturbances in the
northern stream jet, forecast confidence is especially low in the
nitty-gritty forecast details (timing, rain amounts, potential
for thunderstorms). However, its northeastward movement suggests
it could pick up quite a bit of Gulf Moisture, and ensemble
guidance supports this with EPS and GEFS mean PWATs climbing to
1.1-1.4" across our area (the record on our 11.21.00z raob is
1.16"). Unsurprisingly, NBM continues to advertise a 30-50%
probability for rain totals greater than 1 inch area-wide.
Wouldn`t be surprised if we have a few rumbles of thunder with
this system with the unseasonably moist airmass, but mid level
lapse rates look unimpressive and numerous clouds should limit
surface heating, so it would be a little surprising if we saw any
severe weather this far north. Lots can change between now and
then, but we will continue messaging the latest as we see it; stay
tuned.

Bumgardner

&&

.AVIATION...  (For the 12z TAFs through 12z Monday Morning)
Issued at 501 AM CST Sun Nov 16 2025

The area will see continued 10-15 kt northwest winds through this
afternoon due to a strong surface low over the northeast. As high
pressure over the Northern Plains/Upper Midwest sinks into the
region this evening, winds will go slack but we don`t expect any
fog overnight as the airmass remains too dry. In fact, the only
clouds throughout the forecast period will be occasional high
clouds over 20kft.

Bumgardner

&&

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

$$