070
FXUS63 KILX 261708
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1208 PM CDT Wed Jun 26 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms will linger across central
  Illinois today before a cold front passes. Severe weather is not
  expected.

- The next chance for beneficial rainfall will arrive Friday into
  Saturday as another cold front passes through the region.

&&

.UPDATE...
Issued at 956 AM CDT Wed Jun 26 2024

A weak upper trough remains draped over the region this morning,
resulting in a few areas of rainfall as of 10am/15z. The rain
associated with the upper forcing extends from south/west of
Lincoln southward into the MO Bootheel, while further north
showers have developed near an advancing cold front. The 12z ILX
sounding sampled PWAT values of 1.6", while RAP analysis suggests
PWAT values are in the 1.6-1.8" range. Instantaneous rainfall
rates within the most intense showers are anywhere from 1 to
2.5"/hour, so will be monitoring for isolated flooding issues
after yesterday`s rains. Overall, these showers are fairly
progressive (steadily advancing SE), so it seems unlikely that
flooding develops despite the occasionally intense rainfall rates.
Made edits to PoPs to reflect current trends and latest guidance,
but the general PoP trends outlined in the previous forecast
package still hold true.

Erwin

&&

.SHORT TERM...(Today through Thursday)
Issued at 322 AM CDT Wed Jun 26 2024

A short-wave trough evident on 08z/3am water vapor imagery over
northern Minnesota will dig into the Great Lakes today, pushing a
cold front southward into Illinois. Thanks to extensive cloud
cover, the pre-frontal airmass will remain relatively stable with
NAM SBCAPEs generally under 1000J/kg. Despite the meager instability,
lift along/ahead of the front will be sufficient to trigger
scattered showers/thunder across the area...with the greatest
areal coverage occurring along/south of I-70 this afternoon as an
MCV from ongoing convection across Kansas/Missouri approaches from
the west. Have therefore carried low chance PoPs across much of
the KILX CWA..with likely PoPs (60%) focused along/south of I-70.
High temperatures will mostly remain in the lower 80s, but will
climb into the middle 80s along/northwest of the Illinois River
where partial sunshine will be observed by mid to late afternoon.

High pressure will build into the region tonight, leading to
clearing skies and cool overnight lows in the upper 50s and lower
60s. Abundant sunshine and comfortable late June weather will be
on tap for Thursday as high temperatures only reach the lower to
middle 80s.

Barnes

.LONG TERM...(Friday through Tuesday)
Issued at 322 AM CDT Wed Jun 26 2024

A progressive upper flow pattern will dominate the CONUS
throughout the extended...leading to near to slightly below normal
temperatures, as well as periodic rain chances. As the next in a
series of short-wave troughs tracks along the U.S./Canada border,
a cold front will approach from the west late Thursday night.
Showers and a few thunderstorms will develop ahead of the front in
an increasingly moist airmass characterized by precipitable water
values increasing to around 2 inches on Friday...with the highest
PoPs focused along/north of I-72. As the front pushes into central
Illinois, thunderstorms will become more numerous across the board
Friday night into Saturday morning before the boundary settles
southeastward into the Ohio River Valley. Initial storm total rainfall
projections suggest widespread amounts of 0.25 to 1.00...with
locations along/northwest of a Rushville to Bloomington line
potentially picking up 1 to 2 inches.

Once the front passes, a return to cool/dry weather is expected
for Sunday and Monday as highs drop into the upper 70s and lower
80s and lows dip into the middle to upper 50s. After that, another
short-wave will come into the picture by the middle of next
week...bringing the next chance for rain by Tuesday.

Barnes

&&

.AVIATION...  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1207 PM CDT Wed Jun 26 2024

A few showers continue drifting towards the southeast near and along
the I-74 corridor early Wednesday afternoon. These showers have had
a history of producing lightning strikes, and though they`ve
weakened we cannot rule out an isolated additional strike though the
probability appears low (less than 10%) one will occur within 10
miles of BMI and CMI at this time... so it was not mentioned in
their TAFs. VCSH was taken out most locations after around 20-22z
(i.e., 3-5pm CDT), though some guidance is suggesting 10-20% chances
for a light shower ahead of the secondary frontal boundary entering
the area from the northwest late this afternoon. This evening
into tonight, winds will veer to northeasterly as surface high
pressure builds in, maintaining a dry airmass and fostering
continued VFR conditions.

Bumgardner

&&

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

$$