825
FXUS63 KILX 181107
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
507 AM CST Tue Nov 18 2025

.KEY MESSAGES...

- There is a level 1 of 5 (marginal) risk for severe
  thunderstorms today south of a roughly Springfield to Paris
  line. The primary hazard would be hail up to 1 inch in diameter.

- The next opportunity for rain arrives late Thursday into Friday
  night. The axis of heaviest rain has shifted south, but there
  is still a 30-50% chance for rain amounts greater than 1 inch
  along and south of roughly I-70.

&&

.DISCUSSION...
Issued at 113 AM CST Tue Nov 18 2025

***** SHOWERS AND A FEW STORMS TODAY *****

At 1am, scattered showers and a couple thunderstorms were drifting
east-northeastward across southeast and east-central IL. CAMs
suggest additional storms currently forming to our west across
central and northern Missouri may expand in coverage and spread
across the area through morning. KILX`s Vad profiler reveals a
curved hodograph and roughly 700 m^2/s^2 of 0-3km SRH, suggesting
that, despite weak elevated instability (200-500 J/kg MUCAPE), we
could wind up with a feistier storm or two capable of small hail
this morning.

The higher risk for stronger storms will be this afternoon when
various CAMs, including a couple iterations of the HRRR and 2 (of 5)
18z REFS members, indicate additional cells firing as far northwest
as I-55 along the warm front beneath a mid level shortwave trough.
As with this morning`s convection, these storms should be elevated
and hence pose a risk primarily for hail up to 1 inch in diameter,
though if somehow a storm becomes surface based (less than a 2%
chance) then a tornado risk could materialize.

MRMS rain estimates suggests most locations saw anywhere from a few
hundredths to a quarter inch with this first wave, but there are a
couple stripes of over 1 inch where the heavier storms tracked. We
suspect that today`s rain amounts will be similar, with broad totals
of a trace to quarter inch punctuated by pockets of 1"+ driven by
convection.

Temperatures today will run slightly below normal with cool
advection by northeast winds north of the warm front and surface
low. Once again, we blended to the 00z HRRR to knock NBM`s forecast
highs down a couple degrees and have them ranging from the mid-upper
40s north to roughly 60 southwest of a Jacksonville to Lawrenceville
line. Though it should be a dry day, tomorrow will feature similar
temperatures with numerous clouds sticking around throughout the day
to limit surface heating.

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

As a cutoff low lifts out of the Southwest and into the Plains,
difluent southwest flow will advect a slightly more mild airmass
back into the region Thursday with highs area-wide reaching the
upper 50s to low 60s. This system`s northeastward track will allow
it to pull a little more Gulf Moisture northward across the
Mississippi and Ohio Valley Regions, but there is uncertainty in
northward extent of the more robust moisture (PWATs > 1"). Recent
trends in both deterministic and ensemble guidance have been for a
further south low track, which suggests our chances for
substantial rainfall have dropped significantly. The latest NBM
probabilities for over an inch of rain range from 10% in Galesburg
to 30-50% south of I-70, down from 30-60% area-wide at this time
yesterday.

Behind that system, conditions will turn dry with rain chances
generally less than 15% through the weekend. The lack of a strong
cool advection push suggests temperatures will run near to above
normal with daily highs in the 50s. Ensemble guidance suggests next
work week will start off mild, but model spread increases as the
pattern threatens to turn more active mid to late week, by which
time there are some early indications of an impending cool down.

Bumgardner

&&

.AVIATION...  (For the 12z TAFs through 12z Wednesday Morning)
Issued at 505 AM CST Tue Nov 18 2025

A surface low pressure system will shift through central/southern
Illinois today into tonight, resulting in active weather. Showers
and a couple thunderstorms will impact DEC, BMI, and CMI the next
few hours, and then ceilings will lower into the MVFR category at
all the airfields later this morning. A second round of
thunderstorms may develop somewhere in central or southeast
Illinois this afternoon, posing the greatest risk (30-40%) at DEC
and CMI where prob30 groups were maintained from 20-23z (2-5pm
CST). Overnight, HREF suggests a medium (50-60%) chance ceilings
lower further to the IFR category, with perhaps some reduced
visibility as well. Southeast winds 10-15 kt this morning will
back to a northeasterly direction and ease slightly to 7-10 kt
this afternoon.

Bumgardner

&&

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

$$