Waldo, Illinois Weather Forecast Discussion

741
FXUS63 KILX 131437
AFDILX
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
937 AM CDT Sat Sep 13 2025
.KEY MESSAGES...
- An extended period of well above normal temperatures continues
  across central and southeast IL through next Friday with highs
  in the upper 80s to mid 90s expected.
- Marginal risk for severe weather (level 1 of 5) today for areas
  east of a Peoria County to Wayne County line. Strong to severe
  winds is the most likely hazard with these storms.
- Next chance of precipitation comes late next week, with a 30-40%
  chance Thursday into Friday.
&&
.UPDATE...
Issued at 936 AM CDT Sat Sep 13 2025
Main focus this morning has been monitoring the evolution of a WAA-
driven convective system over the northern third of the state.
CAMs have generally had a poor handle on this system. The 13.00z
run of the WRF-ARW was one of the more representative CAMs,
depicting backbuilding along a the associated outflow boundary
which has been observed at times this morning. This particularly
model run has been overdone on the westward extent of storm
development, and is lagging a bit slower than the current
placement of the system, but is still one of the better
representations available.
Over the last half hour, both lightning activity and cloud tops
trends suggest a weakening of these storms. The RAP-analyzed
MUCAPE gradient is near the IL/IN border, so whatever manages to
hold together from this activity is most likely to track along
this gradient towards the northeast parts of our area. That 00z
WRF-ARW run with the best handle on current conditions does not
redevelop any storms later this afternoon, but will be keeping a
close eye on the outflow boundary as an area for potential
redevelopment. Adjusted PoPs for the next few hours to account for
the trends described above, with a 40-50% chance across Champaign
and Vermilion counties and then lower PoPs with south/west
extent.
Erwin
&&
.DISCUSSION...
Issued at 226 AM CDT Sat Sep 13 2025
Ridging overhead will continue to rule the weather pattern to end
out this work week. Temperatures are still building for the weekend
with WAA in place. Highs will be in the 90s for the next week,
dropping to only the mid to upper 60s overnight. The hottest day is
currently forecast to be Sunday, with heat indices of 95-100
degrees. It doesn`t look like these highs in the upper 80s and 90s
will be exiting anytime soon. The global models are showing these
temperatures lasting well into the end of the month. The CPC agrees
and keeps above normal temperatures all the way through the
3-4 week outlook.
A shortwave riding the edge of the existing ridge is influencing a
marginal risk (level 1 of 5) for severe weather from a Peoria County
to Wayne County line and east. Soundings show decent moisture return
aloft and a deep inverted V shape. CAPE is pretty unimpressive, but
effective wind shear will be around 30 knots. An occasional strong
to severe wind gust appears to be the most likely hazard. Most of
the CAMs are showing the storms fizzling out before they get to I-
70, but the NSSL model holds them together through southern IL
(which makes that model the outlier). This round of storms will
enter the northern part of the forecast area around 16z, and be done
between 21z and 23z this evening.
The NAMNest is showing another round developing in IN and moving
westward around 06z, potentially impacting southeastern IL. Often
times these backward propagating systems are a false outcome in the
models, but wanted to mention there is at least a 20-30% chance for
these storms overnight.
Sunday through Wednesday is looking to be dry. More rain chances
return late in the week. The next best chance for rain comes
Thursday into Friday with a 30-40% chance.
Copple
&&
.AVIATION...  (For the 12z TAFs through 12z Sunday Morning)
Issued at 550 AM CDT Sat Sep 13 2025
Generally VFR conditions are expected through the 12z period. The
exception will be in the event of TSRA or SHRA at BMI/CMI/DEC,
where lowered ceilings and/or vis would be possible this
afternoon. Confidence is low if these storms will occur between
18z and 22z.
Winds are generally out of the south, varying by 20-30 degrees at
any point through the period. Winds will be light, less than 10
knots. Where thunderstorms could move through, strong to severe
wind gusts may occur, as there is a risk for severe weather
today.
Copple
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS ILX Office Area Forecast Discussion