Area Forecast Discussion
Issued by NWS Central Illinois

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956
FXUS63 KILX 192347
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
547 PM CST Wed Nov 19 2025

.KEY MESSAGES...

- Low clouds and patchy fog will once again be a concern tonight
  into early Thursday morning.

- Rain will lift into the region Thursday evening, with the
  highest rainfall totals expected to be south of a Quincy to
  Terre Haute line where there is currently a high (50-80%) chance
  of exceeding 0.50"; source 12z REFS.

- A sharp cold front will push through by the middle of next week,
  likely sending overnight temperatures into the 20s (60-90%
  chance), and perhaps making you reconsider running that turkey
  trot; source 13z NBM.

&&

.DISCUSSION...
Issued at 144 PM CST Wed Nov 19 2025

Low stratus and patchy fog are the primary concerns for tonight,
likely reducing visibility once again. This idea is supported by
the synoptic pattern, which features low-level warm advection and
mid-level shortwave energy interacting with a sharpening 925-850
mb baroclinic zone. Occasional sprinkles cannot be ruled out later
tonight, either, especially as cloud ice nuclei return. QPF
appears limited to a couple hundredths or less in any one spot,
though.

A brief period of subsidence then works into west central and
southwest Illinois Thursday morning ahead of the next frontal
system, which will pivot out of the southern Plains and into our
area Thursday evening into Friday. While clouds are unlikely to
scatter out, we should see ceilings lift quite a bit throughout
Thursday morning.

Rain is expected to move into our region later Thursday evening.
However, uncertainty exists regarding the northern extent of this
rain, mainly due to the influence of dry air pushing down from the
Upper Midwest. And to that point, QPF also remains somewhat
uncertain. The highest amounts appear to favor areas south of a
Quincy-to-Terre Haute line, where convective chances are also
highest. Leaning on the latest REFS LPMM QPF output, something in
the realm of 0.25" - 1.5" seems reasonable, with amounts quickly
tapering off to 0.10" or less north of such a line.

Dry and mild weather shall return by the weekend as the frontal
system departs and high pressure builds across the central US.
Afternoon temperatures look on track to warm into the mid-to-upper
50s each Sunday and Monday as low-level warm advection occurs
beneath an amplifying ridge axis.

Attention then turns to the Tuesday-Wednesday timeframe as yet
another frontal system ejects out of the southern Plains and lifts
across our area. Convective chances and moisture return ahead of
the system look limited, perhaps tamping down QPF in the 0.1"-0.5"
range. The bigger story with this frontal system will be the
whipsawing temperatures, with a sharp cold front expected to move
through on Wednesday, ushering in blustery north winds and causing
overnight lows to bottom-out in the 20s for your early morning
turkey trot.

MJA

&&

.AVIATION...  (For the 00z TAFs through 00z Thursday Evening)
Issued at 547 PM CST Wed Nov 19 2025

Low clouds continue to blanket central Illinois late this
afternoon: however, ceilings have improved to MVFR at KPIA/KSPI.
Based on HRRR/RAP forecast soundings, think ceilings will
gradually lower back to IFR across the board after 05z. Minor
visby reductions are present nearly everywhere and with a moist
boundary layer and nearly calm winds, it appears fog will become
thicker/more widespread tonight. The most consistent lower visbys
of 3-5 miles have generally been focused along/north of I-74 from
KBMI to KCMI. Several models including the HRRR/RAP/GFSLAMP
suggest visbys will lower across this area over the next few
hours...with the fog persisting through mid-morning Thursday. As
such, have lowered visby to 1 mile at KCMI after 03z and at KBMI
after 04z. Elsewhere have gone with 2-3 mile visbys from late
evening through 15z Thursday. While the fog will dissipate toward
midday, low ceilings will persist through the entire day. Given a
S/SE wind of 5-10kt, think there will be enough mixing to raise
ceilings to MVFR across the board by afternoon. Other than patchy
drizzle tonight, any significant precip will hold off at the TAF
sites until Thursday night into Friday.

Barnes

&&

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

$$