977
FXUS63 KILX 161844
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
144 PM CDT Wed Apr 16 2025

.KEY MESSAGES...

- Southeast winds gusting 30-40 mph Thursday could cause isolated
  blowing dust where topsoil remains dry.

- Scattered thunderstorms Friday evening, some severe with
  damaging wind gusts and hail.

- Unsettled weather continues through Sunday with a potential for
  2-3" of rain for areas near/south of I-70.

&&

.DISCUSSION...
Issued at 144 PM CDT Wed Apr 16 2025

Lead shortwave energy ejecting out of a western US mid level
trough will bring increasing mid and high level clouds tonight. An
increasing SSW low level jet will allow scattered showers and a
few storms to form late tonight to our west, shifting east into
central IL Thu morning to midday as the LLJ weakens/becomes less
convergent into our area.

A tightening pressure gradient between departing high pressure to
the east and a cold front to the northwest, will bring blustery
SSE winds on Thu, and latest guidance supports 30-40 mph gusts
through the day. RH will be high enough to prevent fire wx
concerns, but with recently drying topsoil and active tilling
ongoing, blowing dust could become a concern - particularly
Thursday afternoon. The blowing dust potential will depend on
coverage of morning showers and storms.

Thursday night, a pronounced elevated mixed layer (EML) works
east into the area. This should tend to keep elevated storms
focused to our north in the IA-WI corridor, and latest CAMs
support this thinking. Forecast sounding show strong capping in
the 900-800 mb layer holding through Friday afternoon. This would
allow for another very breezy, warmer day courtesy of SSW flow.
Mid to high level clouds will affect high temps, but if enough
solar insolation can be realized then widespread low 80s highs
should be realized.

Low pressure tracks into the Great Lakes Friday evening, with a
trailing cold front moving into central IL. Forcing associated
with the front will be sufficient to break the cap. Thermodynamic
environment will support some severe storms (wind/hail) with
clusters or bowing segments the most likely convective mode.
Unidirectional flow within the lowest few km will keep the tornado
threat near zero, limited to storm scale/boundary interaction
that may locally enhance SRH.

Latest ensemble guidance suggests the front will stall out across
the southern half of the CWA through Saturday night, as it becomes
oriented parallel to southwest mid level flow ahead of the slowly
advancing trough. Shortwaves embedded with this flow and ripples
of low pressure tracking up the boundary will bring periods of
showers and storms, primarily south of a Jacksonville to Danville
line based on current guidance. Once again our counties near/south
of I-70 look to be the target of the heavier rainfall. QPF has
inched up to around 2-3" here for 00z Sat to 12z Sun. This will
raise prospects for renewed flooding near creeks/streams and low
lying/poor drainage areas. Will monitor this period for eventual
need of a Flood Watch.

The mid level disturbance finally lifts into the region late this
weekend. Longer range guidance is still struggling with the depth
and location of surface low pressure, so there is a wide range of
solutions at this time. Sunday appears to be the day to watch for
a potentially strong system, which if it tracks northwest of the
area (favored by ECMWF/GEM solutions) would bring another severe
weather and heavy rain risk.


25

&&

.AVIATION...  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1155 AM CDT Wed Apr 16 2025

Surface ridge axis stretched north-south over eastern IL at
midday. As this shifts farther east, light southeast winds will
overspread the terminals this afternoon/evening. After 12z/Thu the
pressure gradient tightens, and we expect 25-30 kt SSE gusts for
much of the daylight hours. High clouds to gradually increase
overnight ahead of the next system. This will spread scattered
showers into central IL Thu morning. Low probabilities of MVFR
ceilings move into areas west of I-55 by late morning. Will keep
VFR going for now and watch trends for MVFR ceilings for the late
morning period in later updates.

25

&&

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

$$