024
FXUS63 KILX 021742
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1242 PM CDT Tue Jul 2 2024

.KEY MESSAGES...

- A couple periods of heavier rain potential exist, one tonight
  west of I-55 and again Wednesday night into Thursday night.

- There will be some strong to severe thunderstorm potential west
  of the Illinois River tonight, and south of I-70 on Wednesday.

- Independence Day will be a bit cooler than normal, though that
  will be offset by muggy 70s dew points. While a dry period
  exists by afternoon, rain chances increase enough during the
  evening to complicate fireworks planning.

&&

.UPDATE...
Issued at 1012 AM CDT Tue Jul 2 2024

Late this morning, warm air advection precipitation continues
across portions of northern Illinois just outside the ILX county
forecast area. Wouldn`t completely rule out a sprinkle or two as
far south as I-74 but expect most of the area to be dry through
the remainder of the morning and afternoon. Meanwhile,
cirrus/cloud cover has began to clear west of a Galesburg to
Effingham line and anticipate areas east of there to clear by
around 1pm. Full sunshine across the area will allow temps to warm
into the mid to upper 80s with a few spots tagging 90F.

Deubelbeiss

&&

.DISCUSSION...
Issued at 258 AM CDT Tue Jul 2 2024

Central Illinois will be in SSE flow today, resulting in decent WAA
and weak moisture return. Highs today will get back up into the
upper 80s and lower 90s, with lows overnight in the 70s. By late
afternoon, a cold front will be approaching to the east. It is
expected to enter the western portion of the CWA around 00-03z this
evening. Strong to severe storms are possible west of the Illinois
River Valley. However, the storms are expected to quickly weaken and
dissipate as they move eastward across central Illinois into more
stable (MUCAPE: couple hundred J/kg) and drier air (dewpoints: 55-65
degrees).

As the front is expected to exit the SE CWA in the mid to late
afternoon tomorrow, storms could refire along the front. These
storms also have the potential to get strong/severe, but the
HRRR/NAMNest indicate that this new CI will be just south/east of
the CWA. Confidence that this second round will affect southeastern
Illinois is not high.

Independence Day (Thursday) will be slightly cooler than normal
which would be great for outdoor celebrations. The downer is that
there are several chances for showers and thunderstorms through the
day. The morning into afternoon has 50-80% POPs (increasing with
southern CWA extent). The activity during this time looks to be
scattered across central Illinois. A brief break in the showers is
possible late in the afternoon. From 00-06z Friday (7pm Thurs-1am
Fri), when firework displays will take place, chances increase again
to 50-60%. This round is just out of reach of the CAMs but the low-
res models show the evening round of precipitation moving through
from west to east starting around 03z Friday (10pm Thursday). If
this forecast checks out, it should give firework celebrations time
to go on. Nevertheless, this forecast is tricky and planning of
events may have some difficulty to them.

Starting Friday, a brief ridging will set up ahead of the next
system that will bring POPs into the area again Sunday. Temperatures
through the weekend will be pleasant, with highs in the low to mid
80s and lows in the mid to upper 60s.

Copple

&&

.AVIATION...  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 1242 PM CDT Tue Jul 2 2024

VFR conditions will be predominant with gusty south winds through
the afternoon. Winds will ease slightly this evening, with an
abrupt shift to westerly or northwesterly at the western
terminals with the arrival of an outflow boundary from the
west/northwest, with scattered thunderstorms approaching quickly
behind it. Given low confidence in timing of storms, we`ve
included a prob30 for the period of concern at each terminal.
Persistent MVFR ceilings are expected for several hours behind
the storms, but cloud bases should rise back into the VFR category late
tomorrow morning into the early afternoon.

Bumgardner

&&

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

$$