702
FXUS63 KILX 011739
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1239 PM CDT Mon Jul 1 2024

.KEY MESSAGES...

- Highs in the upper 70s for today. Temperatures warm back into
  the upper 80s to low 90s starting Tuesday ahead of another cold
  front passage, which will drop temperatures slightly into the
  mid-to-low 80s for the remainder of the week.

- Tuesday evening into Wednesday morning bring a chance for strong
  to severe storms. POPs of 50-75% starting 00z Wednesday. The SPC
  severe outlook shows a slight risk (level 2 out of 5) for our
  western counties.

- Independence Day (Thursday) has a wide spread 60-80% chance for
  precipitation all day. This could put a damper on some
  celebrations that day.

&&

.UPDATE...
Issued at 940 AM CDT Mon Jul 1 2024

A pleasant start to July, with overnight low temperatures in the
upper 40s to lower 50s. Temperatures have rebounded into the mid-
upper 60s as of 9 am, and remain on track to reach the upper 70s
to around 80 degrees.

High pressure over the Great Lakes will keep the easterly flow
going into the afternoon. While some of the high-res models try
to bring some rain into the western CWA later this afternoon, it
appears they are overdoing it as forecast soundings are
substantially dry below 15,000 feet. Only significant impact will
be with an increase of high level clouds, and skies should be
partly sunny by mid afternoon.

Geelhart

&&

.DISCUSSION...
Issued at 259 AM CDT Mon Jul 1 2024

The high pressure in place will linger for today. Keeping
temperatures and dewpoints in a comfortable range. Highs today
getting up into the upper 70s and dewpoints in the 50s. After today,
the high will move off to the east. There is a low pressure system
located in the Upper Plains that will also move off to the east,
bringing some frontal passages to central Illinois starting Tuesday
evening. The warm front will be first to pass through increasing the
day time temperatures into the mid to low 80s and bringing more
moist air (higher dewpoints).

The cold front passage will follow the warm front. Timing of the
front looks to be overnight Tuesday into Wednesday morning. This
front could pose a wind and hail threat to areas to the west of I-
55. Height falls are expected to precede the frontal passage, along
with increasing mid-level flow (50-60kt winds at 500 mb). Recent
trends off the Hi-Res models show it entering the western CWA but
quickly fading in strength as it works its way toward I-55.

POPs stay in the forecast through Friday. Independence Day is this
week on Thursday and, unfortunately, there are 60-80% chance POPs in
the forecast through the entirety of the holiday. Impacts could
cause delays or postponements of festivities. Severity of these
storms are unknown currently, same for any timing ideas.

QPF for the showers and thunderstorms from 00z Wednesday to 12z
Friday have areas NW of the Illinois River and along/south of I-70
receiving 2+ inches. The region between the Illinois River and I-70
could see 1-1.5 inches. However, the 12z LREF shows only a 25%
chance of >2 inches and a 30-60% chance of >1 inch for this time
period. WPC has us in a slight risk in their Excessive Rainfall
Outlook for the next couple days.

Copple

&&

.AVIATION...  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1239 PM CDT Mon Jul 1 2024

Dissipating upstream convection is resulting in scattered to
broken cirrus spreading into central Illinois from the west, which
will continue thinning as it enters our area this afternoon.
Additional upstream VFR clouds will arc into central Illinois
overnight tonight while east-southeast winds ease slightly.
Tomorrow morning, the surface gradient tightens with approaching
low pressure to result in increasing southeast winds which will
gust to 20 kt or higher at times throughout the afternoon.

Bumgardner

&&

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

$$