002
FXUS63 KILX 112007
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
307 PM CDT Thu Jul 11 2024

.KEY MESSAGES...

- Periodic thunderstorm chances will continue into the middle of
  next week, with most of the focus through Tuesday across the
  north half of the state. Severe weather prospects will be
  highest beginning on Sunday.

- Heat and humidity increase this weekend and will likely peak on
  Monday, though 100-degree heat index values may arrive as early
  as Saturday west of I-55.


&&

.DISCUSSION...
Issued at 307 PM CDT Thu Jul 11 2024

Satellite and radar show clouds and scattered showers rotating
along a weak surface boundary, which was analyzed roughly along a
line from Quincy to just north of Indianapolis. Greatest
concentration of showers has been north of the boundary, in an
area best highlighted by the morning NAM Nest run. Precipitable
water values over 1.5 inches continue to support locally heavy
rain as being the primary concern the remainder of the afternoon,
though a few funnel clouds near the boundary can`t be ruled out,
as evidenced by a recent report just south of Champaign. Most of
the showers will be diurnal and fade with sunset, though they may
linger further into the evening south of I-70 as the boundary
settles southward.

The persistent upper trough over the Great Lakes and mid-
Mississippi Valley will remain a focus during the start of the
weekend, but will gradually lift out as high pressure over the
southwest U.S. oozes eastward. Convective concerns begin to shift
to nocturnal thunderstorm complexes, and how far south they will
push. Main storm track will be over the northern Dakotas into the
Great Lakes region, though MCS`s may drop as far south as our
area early next week, as hinted by the GFS/European models. SPC
convective outlooks for Sunday and Monday highlight areas just to
our north, though scattered storms Saturday afternoon may be
strong or locally severe down here (level 1 risk). However,
machine learning outlooks from Colorado State University show a
continued potential through Tuesday. By mid week, more of a
southward push in rain chances will take place, as a deep trough
swings across the Great Lakes region.

Looking at the heat, prospects are increasing for 90 degree
temperatures as early as Saturday, assuming the MCS and associated
cloudiness are not an issue. However, core of the heat still looks
to be Sunday through Tuesday, with heat index values above 100
degrees each day. NBM and WPC guidance highlight best prospects
for heat index over 105 degrees to be on Monday, highest across
the Illinois River valley. The heat breaks on Wednesday as the
cold front pushes southward, and the new CPC 6-10 day outlook
favors below normal temperatures for the following weekend.

Geelhart

&&

.AVIATION...  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 109 PM CDT Thu Jul 11 2024

Scattered showers and possibly an isolated storm are expected mid
afternoon through evening area-wide, with the most likely
locations being BMI, DEC, and CMI. Tonight, lack of cloud cover
and light winds could once again result in a brief period of fog,
for which a group was added to include MVFR visibilities beginning
at 09z/4am (Friday) at BMI, PIA, and SPI.

Copple

&&

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

$$