264
FXUS63 KILX 092331
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
631 PM CDT Mon Jun 9 2025

.KEY MESSAGES...

- Temperatures will be pleasant for early June the next day or so,
  before returning to near 90 degrees on Wednesday. However, no
  significant heat is expected through the weekend.

- Dry conditions prevail through midweek, with showers and
  scattered storms increasing late week into the weekend. No
  organized severe weather is expected at this time.

- A dense layer of wildfire smoke aloft will spread over the the
  region tonight and persist into Tuesday, though surface impacts
  do not appear to be high at this time.

&&

.SHORT TERM...  (Through Late Tuesday Night)
Issued at 217 PM CDT Mon Jun 9 2025

Early afternoon surface map shows the secondary front is closing
in on I-70, with an increase in diurnal cumulus noted along it.
While radar mosaics show quite a bit of development across Indiana
along the boundary, it has not made it into east central Illinois
as of yet. Will maintain some 20% rain chances the remainder of
the afternoon in areas east of I-57. Further northwest, the cold
air stratocumulus has reached Peoria. Some thinning of this takes
place after sunset. However, given the HRRR/RAP vertical
integrated smoke parameters, sky grids have been set to a minimum
of 25% until the smoke plume shifts east of the forecast area
early Tuesday evening. Most of this stays aloft, though lowering
to around 6000 feet for a time on Tuesday. Surface impacts do not
appear to be high at this time, with forecast air quality from the
EPA remaining in the moderate category.

Temperatures will be pleasant for early June, with lows in the
low-mid 50s tonight, reaching near 80 on Tuesday.

.LONG TERM...  (Wednesday through Next Monday)
Issued at 217 PM CDT Mon Jun 9 2025

A cold front that drops southward into the Upper Mississippi
Valley mid week will get hung up near the I-80 corridor, as high
pressure hangs firm over the Appalachians. As a piece of energy
ejects from an upper low over the central and southern Plains,
moisture will be drawn northward, though getting it this far east
will be problematic for a couple of days. If any area had any rain
before Friday morning, it probably would be over the northern CWA,
closest to the front. While temperatures approach 90 degrees on
Wednesday over areas northwest of I-55, humidity levels remain low
enough to keep the heat index close to actual temperature.

Getting into the weekend, the low itself tries to make a push
northeast, indicated by the international models, which should
finally draw the front southward. While not a complete washout,
rain chances increase beginning Friday, with the highest chances
both Saturday (especially) and Sunday afternoons.

While upper level ridging develops along the east slopes of the
Rockies early next week, not much eastward push is expected
initially. This will keep our air mass more of a Pacific origin,
with temperatures in the low to mid 80s for highs.



Geelhart

&&

.AVIATION...  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 631 PM CDT Mon Jun 9 2025

VFR conditions will prevail through the entire 00z TAF period.
Bands of SCT-BKN clouds at around 6000-7000ft will persist into
the evening before gradually dissipating overnight. NAM forecast
soundings and Cu-rule suggest a generally clear day on Tuesday
with just FEW-SCT diurnal Cu developing at around 5000ft. A plume
of smoke aloft evident on 2315z/615pm visible satellite imagery
from the eastern Dakotas southward into Missouri will gradually
spread eastward tonight into Tuesday, creating a hazy overcast.
HRRR/RAP surface-based smoke forecast currently focuses highest
concentrations across the eastern Dakotas where visbys are reduced
to 5-6 miles in places. Some of this smoke is progged to make its
way into central Illinois on Tuesday, although with reduced
concentrations. Have opted to leave visby restrictions out of the
forecast at this time, but this will need to be examined more
closely with future TAF issuances. Northwesterly winds will
continue to gust 10-20kt for the next hour or so before backing
to westerly and decreasing to less than 10kt by sunset.

Barnes

&&

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

$$