444
FXUS63 KILX 242303
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
603 PM CDT Tue Jun 24 2025

.KEY MESSAGES...

- Hot and humid weather continues this week with high temperatures
  peaking in the low to middle 90s and afternoon heat of 95 to 105
  through Thursday.

- Daily chances for widely scattered showers and storms will be
  seen through the weekend (20-50%). However, the most widespread
  rainfall will remain northwest of the area.

- Typical late June temperatures (middle to upper 80s) and lower
  dewpoints make a return by the early to middle parts of next
  week as a stronger cold front pushes through the area.

&&

.DISCUSSION...
Issued at 236 PM CDT Tue Jun 24 2025

...Heat Advisory for Most Through Thursday, Relief Comes Next Week...

An upper ridge of high pressure remains locked in over the eastern
US, with a frontal boundary stretched from the central Plains into
the eastern Great Lakes Region. This frontal boundary separates a
hot and humid airmass to its east and southeast from a cool, low
dewpoint airmass to its west and northwest. High temperatures over
the next several days will peak in the low to middle 90s with
maximum afternoon heat indices ranging from 95 to 100, though
urban areas could approach 105. Although heat indices have
trended down slightly the last few days, the extended period of
oppressive heat with little relief at night still warrants a Heat
Advisory for most.

The nearby frontal boundary will remain mostly stationary with
subtle shifts north and southward through the weekend. Relief
from heat should come by the early to middle parts of next week
as a stronger cold front works through the area, bringing the
return of seasonal temperatures and lower dewpoints.

...Daily Precipitation Chances Through the Weekend...

The aforementioned frontal boundary positioned off to our northwest
will be the focus for daily precipitation opportunities through
the weekend, with the highest chances being during the afternoon
and evening hours (20-50%). As of 19Z, the front is roughly
positioned from central Iowa northeastward into southern
Wisconsin. It will continue to sag southward some today as an
upper shortwave working across southern Canada attempts to flatten
the upper ridge. Several remnant outflow boundaries have been the
focus for shower and thunderstorm development since early this
afternoon, especially in east- central and southeast Illinois. As
the front nears closer this evening, CAMS show showers/storms
potentially clipping our north of I-74 counties through the
overnight hours. Moderately strong instability will allow storms
to develop rather quickly, however weak shear will ultimately lead
to lack of organization. Because of this, collapsing updrafts
could produce damaging downburst winds with any of the stronger
storms.

Little movement in the front on Wednesday will lead to a similar
setup by afternoon into evening. The front will lift back northward
going into Thursday as a low in the southwest US lifts into the
central Plains states, keeping better chances for any
precipitation to our north. This will ultimately act to further
break down the blocking ridge over the eastern CONUS late this
week into the weekend, with the front then expected to gradually
drop back southward toward the area before drifting into the
northeast US later this weekend.

NMA

&&

.AVIATION...  (For the 00z TAFs through 00z Wednesday Evening)
Issued at 603 PM CDT Tue Jun 24 2025

Isolated TSRA have been focused north and south of the central IL
terminals through late afternoon. Cannot rule out an isolated
storm impacting a terminal this evening, but feel chances (under
20%) are too low to mention in TAFs - with the exception of KPIA
where a PROB30 is maintained through 03z due to a weak convergence
zone just to their northwest. Scattered -TSRA will redevelop over
the area Tue afternoon and have included PROB30 at all sites.
Aside from the storm risk, VFR skies with scattered high clouds
tonight and diurnal cu on Tue. Light/variable winds tonight will
become SW at 5-10 kt by late morning.

25

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT Thursday for ILZ029-031-036>038-
040>057-061>063-066>068-071>073.

&&

$$