438
FXUS63 KILX 072350
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
650 PM CDT Fri Jun 7 2024

.KEY MESSAGES...

- A decaying thunderstorm complex will arrive late tonight into
  early Saturday morning...with the highest rain chances (60-90%)
  focused along/south of a Macomb to Mattoon line.

- Near to slightly below normal temperatures will continue for the
  next several days before the return of summertime warmth with
  temperatures in the middle to upper 80s by the end of next
  week.

&&

.SHORT TERM...(Tonight through Saturday)
Issued at 248 PM CDT Fri Jun 7 2024

A short-wave trough dropping southeastward across Saskatchewan and
Montana is providing the necessary synoptic lift for thunderstorm
development across Nebraska this afternoon. 19z/2pm satellite
mosaic shows cells blossoming over far southern South Dakota into
central Nebraska and these are expected to become more numerous
and spread southeastward this evening...eventually aided by a
50-60kt 850mb jet oriented northeastward from the Texas panhandle.
The storms will push into Missouri later this evening, then will
spill into parts of central Illinois overnight. Most CAMs keep the
bulk of the convection just S/SW of the KILX CWA, but bring
showers into parts of the area before dawn Saturday. Based on
current satellite trends and the 18z HRRR, have focused highest
PoPs along/south of a Macomb to Mattoon line from 09z/4am to
15z/10am. Instability will be meager as NAM MUCAPE values remain
below 100J/kg. Nevertheless have included slight chance for
thunder due to strong LLJ curving northeastward toward central
Illinois toward dawn.

Once the early morning showers depart into Indiana, mostly dry
weather is anticipated for the remainder of Saturday. A weak cold
front will push into the area from the northwest, so cannot rule
out widely scattered showers/thunder during the afternoon/evening,
but think most locations will remain dry. Have held on to chance
PoPs south of I-70 into Saturday night as the front settles
southward into the Ohio River Valley, but it appears the bulk of
the convection associated with the nocturnal jet will occur well
S/SW across Missouri into western Kentucky.

Barnes

.LONG TERM...(Sunday through Next Friday)
Issued at 248 PM CDT Fri Jun 7 2024

Cool and predominantly dry weather is expected early next week
with highs in the 70s and lows in the 50s Sunday through Tuesday.
Coolest night will be Monday night when lows perhaps dip into the
upper 40s along/north of the I-74 corridor. After that, upper
heights will rise and temperatures will climb back above normal
into the middle and upper 80s by next Thursday/Friday.

Barnes

&&

.AVIATION...  (For the 00z TAFs through 00z Saturday Evening)
Issued at 650 PM CDT Fri Jun 7 2024

Mid-level cloud deck at around 15000ft will continue to stream
across the sky through the evening before a decaying convective
complex approaches from the west overnight. Given the initially
very dry airmass and the fact that that convection currently
developing in Nebraska will drop southeastward into Missouri and
mainly stay S/SW of central Illinois, have limited precip mention
in the 00z TAFs. Opted to include predominant showers for a few
hours at KSPI after 10z and at KDEC after 14z, but have only
carried VCSH at the other terminals. Ceilings will lower Saturday
morning, but perhaps not as much as the CONSShort guidance would
suggest. Based on NAM forecast soundings, have lowered ceilings to
MVFR after the 14z-16z time period and kept them there through
00z. Winds will become light/variable this evening, then will
become S at 10-15kt Saturday morning. Winds will then veer to SW
and decrease to 10kt or less after 21z as a cold front settles
southward into central Illinois.

Barnes

&&

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

$$