173
FXUS63 KILX 222014
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
314 PM CDT Sun Sep 22 2024

.KEY MESSAGE...

- Off and on showers will continue through Tuesday. Storm total
  rainfall will be greatest along and south of the I-72 corridor
  where 1 to 2 inches will occur.

&&

.SHORT TERM...(Tonight through Monday)
Issued at 314 PM CDT Sun Sep 22 2024

19z/2pm surface analysis shows a cold front between the Illinois
River and the I-55 corridor. Scattered showers are beginning to
re-develop ahead of the boundary...particularly east of I-55.
Think areal coverage will continue to increase over the next
couple of hours, resulting in 60-70 PoPs across the E/SE KILX CWA
through the remainder of the afternoon and into the early evening.
The front will settle southeastward tonight, eventually stalling
just north of the Ohio River overnight. With forcing shifting to
the south and slightly drier air advecting into the region behind
the departing cold front, think early evening showers will come
to an end and mostly dry weather can be anticipated overnight.
Low temperatures will range from the middle 50s northwest of the
Illinois River...to the middle 60s south of I-70.

The front will remain stalled across the Ohio River Valley on
Monday as a short-wave trough evident on latest water vapor
imagery over Colorado approaches from the west. Showers and a few
thunderstorms will develop in the vicinity of the boundary...with
the best rain chances during the day remaining focused south of
I-70. As the wave gets closer and a weak surface low develops and
tracks along the front, increased synoptic lift will bring another
round of light to moderate rain to much of central Illinois Monday
night.

Barnes

.LONG TERM...(Tuesday through Next Sunday)
Issued at 314 PM CDT Sun Sep 22 2024

Showers will be ongoing Tuesday morning, but will shift eastward
and come to an end from west to east during the afternoon. Storm
total rainfall from yesterday through Tuesday will be greatest
along/south of I-72 where amounts of 1 to 2 inches will be common.

After a period of dry weather Tuesday night into Wednesday, the
forecast for later in the period becomes a bit more complex as a
short-wave trough currently over northern Alberta digs southeastward
and cuts off over the Mississippi River Valley by mid to late
week. The exact evolution of this process remains unclear as
synoptic model solutions vary. Another complicating factor will be
the presence of a potential tropical system most models are
forecasting to track northward through the Gulf of Mexico by
Thursday/Friday. This system will likely shunt the upper low N/NW
as it approaches the Gulf Coast...potentially bringing an extended
period of scattered showers to portions of the Midwest Thursday
through the upcoming weekend. Some solutions even suggest tropical
moisture may be entrained by the upper low, although this does not
seem particularly plausible. End result is a low confidence
forecast featuring low chance PoPs for the end of the week into
next weekend.

Barnes

&&

.AVIATION...  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1239 PM CDT Sun Sep 22 2024

17z/12pm surface analysis shows a cold front west of the Illinois
River...with scattered showers along and ahead of the front.
Ceilings are predominantly MVFR across central Illinois: however,
a narrow corridor of IFR persists in the vicinity of the boundary
currently impacting KPIA. Based on HRRR/RAP frontal timing, have
veered winds to W/NW and improved ceilings to MVFR at KPIA by 20z.
Further east, have maintained MVFR ceilings and shower mention
through the afternoon. The front will gradually work south of the
terminals by early this evening, followed by largely dry
conditions with winds veering to NW and eventually to N/NE by late
tonight into Monday morning. Forecast soundings suggest MVFR
ceilings will persist at most sites, but may temporarily improve
to VFR at KPIA this evening before once again lowering to MVFR by
dawn Monday.

Barnes

&&

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

$$