976
FXUS63 KILX 190230
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
830 PM CST Tue Nov 18 2025

.KEY MESSAGES...

- There is a level 1 of 5 (marginal) risk for severe thunderstorms
  today south of a roughly Pana 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 chance for rain amounts greater than 1 inch south of
  I-70.

&&

.UPDATE...
Issued at 830 PM CST Tue Nov 18 2025

Late evening surface analysis shows an area of low pressure
centered along the Ohio Valley with high pressure in place over
the west-central Great Lakes Region. Shower/storm activity has
pushed off to our south, with an expansive blanket of low stratus
that has filled in behind it. Patchy dense fog has been reported
south of I-70 where heavy rain fell earlier and stratus is more
patchy. Visibility has improved some over the last hour or so as
widespread stratus enters. Because of this, dense fog chances
through the rest of tonight appear relatively low. Further north,
drizzle is ongoing where subtle lift tied to a couple weak upper
impulses coincides with trapped low-level moisture. Periods of
drizzle look to continue through late tonight, with the focus
being near and north of a Macomb to Champaign line over the next
few hours.

NMA

&&

.DISCUSSION...
Issued at 103 PM CST Tue Nov 18 2025

The low pressure system is moving eastward today, with a warm front
draped over the southeastern part of the CWA. SPC has maintained a
marginal risk (level 1 of 5) of severe weather for south of a Pana
to Paris line. The dewpoint gradient looks to be along the southern
CWA border. The triple point is expected to move through southern IL
this afternoon, which would increase the chances for severe storms
with hail, wind, or even a tornado, the further south you travel
through the state. South of I-70, the CAMs show 1000-1200 J/kg of
MUCAPE and ~30 knots of effective wind shear. The freezing level is
around 9k-10k ft. Most (if not all) of the storms that develop down
there today will be elevated, supporting the hail threat. However,
if one of these storms can latch onto a boundary or become surface
based, a tornado could spin up.

For an example of how the afternoon redevelopment could go, let`s
take a look at the HRRR. The HRRR shows a corridor of strong (maybe
severe) storms traveling east along the I-64 corridor, just south
of our CWA, from 19z-23z. The NAMnest is more north, with the
storms stretching to the I-70 corridor. Area of concern for our
forecast area would be approximately the I-70 corridor and south.
Currently, the NAMNest looks to be initializing the general area
of the ongoing cells the best.

Wednesday would be a brief break in the rain as there is a lull
between systems. Early Thursday morning, another low pressure system
will pass through central and southeastern IL, bringing increased
Gulf moisture and slightly warmer temperatures in for Thursday.
Above freezing temperatures keep the precipitation type rain,
thankfully. This system could deliver higher rainfall amounts
compared to the ongoing system. From Thursday morning to Saturday
morning, QPF of 1-1.5 inches is in the forecast.

Temperatures stay near or just above normal for the next week. The
warmest day this week is Thursday with highs in the upper 50s to low
60s and lows in the upper 40s to low 50s. Behind the low pressure
system Friday, temperatures will drop back down to near normal.

Copple

&&

.AVIATION...  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 523 PM CST Tue Nov 18 2025

A surface low is passing by to our south this evening, which has
allowed winds to back to the north-northeast. Low stratus will
expand across the area tonight, with most sites already down to IFR
category just before 00Z. Patchy drizzle or fog is possible
overnight, bringing periods of reduced visibility. Stratus will
be slow to erode, with more optimistic guidance suggesting
ceilings will return to VFR by Wednesday afternoon. Winds will
veer to the east later in the period with speeds becoming light as
high pressure slides by to our north.

NMA

&&

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

$$