963
FXUS63 KILX 171433
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
933 AM CDT Tue Sep 17 2024

.KEY MESSAGES...

- Summer-like warmth continues through the end of the week with
  daytime highs in the middle 80s to near 90.

- Precipitation looks more promising later in the forecast period
  as a few frontal systems bring rain chances back late this week
  and again this weekend into early next week.

&&

.UPDATE...
Issued at 933 AM CDT Tue Sep 17 2024

Forecast area remains in a mostly clear region this morning,
between the rex block to our east, and a band of cloudiness that
extends from Kansas into northwest Wisconsin. A small patch of
mid-level clouds is located just south of a Springfield to
Effingham line, though some erosion is already noted on the
northwest flank. Good mixing will allow dew points to drop into
the mid to upper 40s this afternoon over most of the area this
afternoon, so despite highs in the upper 80s, apparent
temperatures will run a few degrees cooler.

Geelhart

&&

.DISCUSSION...
Issued at 153 AM CDT Tue Sep 17 2024

Nighttime Microphysics satellite imagery shows clear skies over the
state of Illinois early this morning. Dewpoints as of 2 am are
sitting in the 50s, with the lowest readings in east-central
Illinois. Temperatures will continue to fall, bottoming out in
the middle to upper 50s over the next few hours.

A Rex block remains stoutly in place over the eastern CONUS with
strong high pressure ridging over the northeast US and an upper low
over the southeast. The remnants of Tropical Depression Eight will
continue to slowly move inland today before becoming stationary as
it encounters ridging. Moisture associated with this feature will
remain east of here, with the weather pattern staying dry until
later in the week. Daytime highs will continue to sit between 5-10
degrees warmer than normal for mid September. However, a lower
dewpoint airmass will favor more seasonable lows the next few nights.

Precipitation chances begin to increase later this week as an upper
trough currently situated over the southwest CONUS emits shortwaves
northward, acting to break down the strong upper ridge. The first
frontal system will bring a cold front toward the area late Thursday
night into Friday, introducing low end precipitation chances to
locales west of I-55. The front looks to stall or wash out as it
encounters upper ridging, so rain amounts don`t look overly
impressive. However, some guidance suggests daytime heating on
Friday may reinvigorate the boundary and perhaps support a few
storms. The NBM came in dry during that period for now, but this may
need to be increased in future forecast cycles.

A stronger wave will lift north through the Plains states this
weekend. Subtle shortwaves ahead of this feature will increase rain
chances Saturday night into Sunday as a warm front lifts through the
area. The system`s cold front will approach Sunday night into
Monday, bringing a better push of moisture advection especially west
of I-55. A strong LLJ should support some storms with FROPA, but
unfavorable timing should keep any severe threat west of here.
Ensemble probabilities for receiving at least 0.50" of rain through
early next week are highest west of I-55 (30-40%), with lower
chances east of there. However, storm activity could increase total
amounts.

Temperatures look to briefly return back to our seasonable norms
(upper 70s to low 80s) late this weekend into early next week.
Longer range guidance is split on whether the seasonable
temperatures will persist through next week with the GFS favoring
longwave troughing lingering over the central CONUS (cooler) and the
ECMWF indicating ridging building back in (warmer). For now, the
Climate Prediction center still favors warmer than normal
temperatures from the middle of next week through the end of the
month.

NMA

&&

.AVIATION...  (For the 12z TAFs through 12z Wednesday Morning)
Issued at 515 AM CDT Tue Sep 17 2024

VFR conditions with mostly clear skies and light easterly winds are
expected through the TAF duration.

NMA

&&

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

$$