975
FXUS63 KILX 151120
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
520 AM CST Sat Nov 15 2025

.KEY MESSAGES...

- The area will have one more day of near record warmth with
  highs in the low to mid 70s today. This evening into tonight,
  conditions turn seasonably cooler with morning lows in the 30s.

- The next chance (60-70%) for precipitation arrives Monday into
  Tuesday. This will do little to aid the ongoing drought
  conditions, with only a 15-30% chance for more than a half inch
  of rainfall north of I-70.

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

&&

.DISCUSSION...
Issued at 1256 AM CST Sat Nov 15 2025

***** NEAR RECORD WARMTH TODAY, COOLER TOMORROW *****

At 1am Saturday morning, satellite imagery revealed a large area of
mid to high clouds across the Midwest along and ahead of a large
trough in the Northern Plains and Southern Canadian Prairies. Thanks
to cloud cover and 10-15 mph southerly winds, temperatures at the
surface were in the upper 50s to low 60s, where they`ll likely
hover through sunrise when surface heating returns to boost them
into the low 70s; this would result in record warm low
temperatures, but the cooler air arriving behind a cold front this
evening will probably bring daily lows into the mid 40s-low 50s -
well shy of record values. That front will sweep the area from
northwest to southeast to bring a wind shift and lower dewpoints
between mid morning (Galesburg) and early evening (Lawrenceville),
but there`s not a particularly strong push of cold air
immediately behind it. The cool advection picks up during the
evening when temperatures (dewpoints) will fall through the 50s
(30s) and north-northwest winds will gust 20-25 mph. The breeziest
conditions today will likely be ahead of the cold front between
mid morning and early afternoon, during the period of overlap
between onset of diurnal mixing and the waning LLJ (30-40 kt at
925mb) when soundings suggest a few hours of gusts to 30+ mph in
east-central IL.

Cloud cover will be minimal tonight, though there will likely be
just enough wind to keep temperatures from completely bottoming out.
Still, morning lows are forecast to fall solidly into the 30s
everywhere north of I-70 - back to seasonable values. Highs will
also run close to normal in the low to mid 50s, with winds going
light and variable late in the day as the surface high moves right
into central IL. Depending on cloud cover tomorrow night, lows may
fall a little more than currently forecast (around 30) with many
locations dipping into the mid 20s by dawn Monday morning.

***** MULTIPLE OPPORTUNITIES FOR PRECIP NEXT WEEK *****

Global deterministic models are in general agreement that a
shortwave trough drifts across the middle Mississippi Valley and
Midwest Monday into Tuesday, bringing central and southeast IL a
solid opportunity (50-70% probability) for light precipitation. As
noted on the day shift yesterday, NBM and LREF probabilities have
trended downward on potential for any wintry precipitation/snow
across our area as guidance has come into agreement on a northern
track for the mid level trough - keeping snow potential solidly
north of I-80. Instead, the warmer and more humid airmass may lend
itself to a few rumbles of thunder across southern portions of the
ILX CWA as forecast soundings indicate a smidgen of elevated
instability and LREF probabilities run 30-50% for more than 100 J/kg
of MUCAPE south of ~I-72 Monday night. Unfortunately, it appears
unlikely that we`ll receive enough rainfall to make much difference
to the ongoing severe drought north of I-70 where NBM gives only a
15-30% chance for more than a half inch.

Behind that system, Wednesday is shaping up to be a rain-free day
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 are
currently in the mid 50s, but one shouldn`t be surprised if it gets
a little warmer with some sunshine.

All attention then turns to the next system, depicted generally as a
cut off low in the Desert Southwest getting picked up by a northern
stream wave and swept through the Mississippi River Valley.
Divergence in the right entrance region of the upper jet should
foster surface cyclogenesis beneath this wave somewhere nearby,
though the strength and precise track of the low remain unclear at
this time. Given the general movement of the system - from south-
southwest to north-northeast - it makes conceptual sense that this
low will be capable of pulling some Gulf moisture northward into the
district, which could spell some juicier rainfall amounts. The NBM
indicates a 30-50% chance for more than an inch Thursday evening
into Friday morning, which, while nowhere near enough to eradicate
the drought, could offer some help. In addition, though the chance
is low, we can`t completely write off some localized heavier amounts
with the ECMWF Extreme Forecast Index (EFI) showing a shift of tails
(SOT) area-wide Thursday-Friday - indicating the top 10% (wettest)
of its membership are above the 99th percentile of the M-climate, or
previous model forecasts for the 5-week period centered on November
21. Stay tuned as we fine tune forecast rain amounts.

Bumgardner

&&

.AVIATION...  (For the 12z TAFs through 12z Sunday Morning)
Issued at 519 AM CST Sat Nov 15 2025

Expect an uptick in southwest winds with gusts to 25 kt when
diurnal mixing taps into a weakening LLJ around 15-16z (9-10am
CST). A dry cold front will then cross the airfields from
northwest to southeast between 18z-21z (noon-3pm CST), resulting
in diminishing clouds and causing winds to veer northwesterly.
Flight conditions should remain VFR through the forecast period.

Bumgardner

&&

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

$$