286
FXUS63 KILX 171135
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
535 AM CST Mon Nov 17 2025

.KEY MESSAGES...

- Rain will spread west to east across the area this evening into
  tonight, with a few showers lingering through tomorrow. Most
  locations will see rain amounts between a tenth and half an inch
  (80% chance).

- The next opportunity for beneficial rainfall arrives late
  Thursday into Friday. There is a 30-60% chance (highest south)
  for rain amounts greater than 1 inch.

&&

.DISCUSSION...
Issued at 156 AM CST Mon Nov 17 2025

***** SHOWERS TONIGHT INTO TOMORROW *****

Early Monday morning, water vapor satellite imagery reveals an upper
level trough spinning in the Great Basin, with shortwave ridging
ahead of it in the Great Plains and Mississippi River Valley. Both
features will shift east today, resulting in increasing cloud cover
and, by tonight, rain showers along and in advance of a warm front.
This still isn`t looking like a significant rainfall event, but
PWATs climbing to around 0.75-1.00" (around the 90th percentile of
climatology) per HREF/REFS mean could still favor some pockets of
half inch or greater amounts with the heaviest cells given the deep
layer of "skinny" CAPE apparent in forecast soundings. Through
tomorrow morning, HREF`s 10-90th percentile range for rain totals
spans roughly a tenth to half inch area-wide, though slightly higher
south of I-70.

With the upper level shortwave passing overhead and the surface low
nearby, NBM and HREF suggest low level clouds are going to stick
around most or all of the day tomorrow, with perhaps a couple light
showers as well (20-30% chance). In addition, north of the surface
low, cool advection by east-northeast winds will confine
temperatures to the 40s. The exact low track is not quite nailed
down at this time, but we did knock a couple degrees off of NBM`s
forecast which had highs in the mid 50s to mid 60s.

Surface high pressure will settle back into the region in the wake
of that system on Wednesday, resulting in drier weather conditions,
though we`ll still have some clouds around as we find ourselves near
the northern periphery of weak ridging across the Ohio and Tennessee
Valleys. Temperatures will run near or slightly above seasonable
normals with forecast highs in the low to mid 50s.

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

At some point Thursday into Friday, a cutoff low in the Southwest
will meander northeastward across the Southern/Central Plains and
into the Mississippi Valley. The dipole in EOF1 for 500mb heights
suggests the primary source of forecast variance among the Low
Resolution Ensemble Forecast (LREF) system`s members is coming from
differences in the speed at which this trough moves east into our
area, so unsurprisingly the NBM (and hence our forecast) has a long
duration of PoPs beginning as early as Wednesday night. In general,
the global models and their respective ensembles have trended slower
with the storm`s arrival and hence later with the onset of rain
locally, but low confidence precludes any big PoP adjustments at
this juncture. One shouldn`t be surprised, however, if even a
portion of the day Thursday winds up being dry and most of any rain
we receive falls between Thursday night and Friday evening. Chances
for rain totals over 1 inch generally range from 30-60% across the
area, with the highest chances south of roughly the I-72 corridor
given a recent slight southward shift in the low`s track. We may
also wind up with a couple rumbles of thunder across our southern
counties, but severe weather potential still looks limited at this
time given poor mid level lapse rates and cloud cover mitigating
surface heating.

Temperatures are looking mild on Thursday as warm and moist
advection overspreads much of the region in advance of the trough;
NBM advertises a 40-70% chance for highs over 60 degrees southwest
of a roughly Macomb to Paris line. Friday could still be on the mild
side, though prolific cloud cover and ongoing rain in much of the
area may limit surface heating. Temperatures look to trend closer to
seasonable normals over the upcoming weekend, though, as we get a
weak push of cool advection behind that system.

Bumgardner

&&

.AVIATION...  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 529 AM CST Mon Nov 17 2025

As surface high pressure shifts east into the Ohio Valley, winds
will return from the southeast today at around 10-13 kt.
Altostratus around FL070 will slowly shift east this morning,
with a more notable increase in clouds this evening as a warm
front approaches. That front will also spark some showers and
possibly a thunderstorm overnight into Tuesday morning, though the
probability of thunder (15%) was too low to warrant a prob30
group at this time. Ceilings will lower Tuesday morning, and HREF
and NBM suggest probabilities for MVFR or lower ceilings will
climb to 80-90% by roughly 15z/9am CST. Used FEW025 to hint at the
increasing risk of an MVFR ceiling toward the end of the period.

Bumgardner

&&

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

$$